| 1. |
- Lind, Ulrika, et al.
(författare)
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Analysis of aquaporins from the euryhaline barnacle Balanus improvisus reveals differential expression in response to changes in salinity
- 2017
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:7
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Tidskriftsartikel (refereegranskat)abstract
- Barnacles are sessile macro-invertebrates, found along rocky shores in coastal areas worldwide. The euryhaline bay barnacle Balanus improvisus (Darwin, 1854) (= Amphibalanus improvisus) can tolerate a wide range of salinities, but the molecular mechanisms underlying the osmoregulatory capacity of this truly brackish species are not well understood. Aquaporins are pore-forming integral membrane proteins that facilitate transport of water, small solutes and ions through cellular membranes, and that have been shown to be important for osmoregulation in many organisms. The knowledge of the function of aquaporins in crustaceans is, however, limited and nothing is known about them in barnacles. We here present the repertoire of aquaporins from a thecostracan crustacean, the barnacle B. improvisus, based on genome and transcriptome sequencing. Our analyses reveal that B. improvisus contains eight genes for aquaporins. Phylogenetic analysis showed that they represented members of the classical water aquaporins (Aqp1, Aqp2), the aquaglyceroporins (Glp1, Glp2), the unorthodox aquaporin (Aqp12) and the arthropod-specific big brain aquaporin (Bib). Interestingly, we also found two big brain-like proteins (BibL1 and BibL2) constituting a new group of aquaporins not yet described in arthropods. In addition, we found that the two water-specific aquaporins were expressed as C-terminal splice variants. Heterologous expression of some of the aquaporins followed by functional characterization showed that Aqp1 transported water and Glp2 water and glycerol, agreeing with the predictions of substrate specificity based on 3D modeling and phylogeny. To investigate a possible role for the B. improvisus aquaporins in osmoregulation, mRNA expression changes in adult barnacles were analysed after long-term acclimation to different salinities. The most pronounced expression difference was seen for AQP1 with a substantial (>100-fold) decrease in the mantle tissue in low salinity (3 PSU) compared to high salinity (33 PSU). Our study provides a base for future mechanistic studies on the role of aquaporins in osmoregulation. © 2017 Lind et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 2. |
- Lind, Ulrika, et al.
(författare)
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Molecular Characterization of the alpha-Subunit of Na+/K+ ATPase from the Euryhaline Barnacle Balanus improvisus Reveals Multiple Genes and Differential Expression of Alternative Splice Variants
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- The euryhaline bay barnacle Balanus improvisus has one of the broadest salinity tolerances of any barnacle species. It is able to complete its life cycle in salinities close to freshwater (3 PSU) up to fully marine conditions (35 PSU) and is regarded as one of few truly brackish-water species. Na+/K+ ATPase (NAK) has been shown to be important for osmoregulation when marine organisms are challenged by changing salinities, and we therefore cloned and examined the expression of different NAKs from B. improvisus. We found two main gene variants, NAK1 and NAK2, which were approximately 70% identical at the protein level. The NAK1 mRNA existed in a long and short variant with the encoded proteins differing only by 27 N-terminal amino acids. This N-terminal stretch was coded for by a separate exon, and the two variants of NAK1 mRNAs appeared to be created by alternative splicing. We furthermore showed that the two NAK1 isoforms were differentially expressed in different life stages and in various tissues of adult barnacle, i.e the long isoform was predominant in cyprids and in adult cirri. In barnacle cyprid larvae that were exposed to a combination of different salinities and pCO(2) levels, the expression of the long NAK1 mRNA increased relative to the short in low salinities. We suggest that the alternatively spliced long variant of the Nak1 protein might be of importance for osmoregulation in B. improvisus in low salinity conditions.
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| 3. |
- Wrange, Anna-Lisa, 1981, et al.
(författare)
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The Story of a Hitchhiker: Population Genetic Patterns in the Invasive Barnacle Balanus (Amphibalanus) improvisus Darwin 1854
- 2016
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the ecological and evolutionary forces that determine the genetic structure and spread of invasive species is a key component of invasion biology. The bay barnacle, Balanus improvisus (= Amphibalanus improvisus), is one of the most successful aquatic invaders worldwide, and is characterised by broad environmental tolerance. Although the species can spread through natural larval dispersal, human-mediated transport through (primarily) shipping has almost certainly contributed to the current global distribution of this species. Despite its worldwide distribution, little is known about the phylogeography of this species. Here, we characterize the population genetic structure and model dispersal dynamics of the barnacle B. improvisus, and describe how human-mediated spreading via shipping as well as natural larval dispersal may have contributed to observed genetic variation. We used both mitochondrial DNA (cytochrome c oxidase subunit I: COI) and nuclear microsatellites to characterize the genetic structure in 14 populations of B. improvisus on a global and regional scale (Baltic Sea). Genetic diversity was high in most populations, and many haplotypes were shared among populations on a global scale, indicating that longdistance dispersal (presumably through shipping and other anthropogenic activities) has played an important role in shaping the population genetic structure of this cosmopolitan species. We could not clearly confirm prior claims that B. improvisus originates from the western margins of the Atlantic coasts; although there were indications that Argentina could be part of a native region. In addition to dispersal via shipping, we show that natural larval dispersal may play an important role for further colonisation following initial introduction.
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| 4. |
- Abramova, Anna, 1990, et al.
(författare)
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Sensory receptor repertoire in cyprid antennules of the barnacle Balanus improvisus
- 2019
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:5
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Tidskriftsartikel (refereegranskat)abstract
- - Barnacle settlement involves sensing of a variety of exogenous cues. A pair of antennules is the main sensory organ that the cyprid larva uses to explore the surface. Antennules are equipped with a number of setae that have both chemo- and mechanosensing function. The current study explores the repertoire of sensory receptors in Balanus improvisus cyprid antennules with the goal to better understand sensory systems involved in the settling behavior of this species. We carried out transcriptome sequencing of dissected B. improvisus cyprid antennules. The generated transcriptome assembly was used to search for sensory receptors using HMM models. Among potential chemosensory genes, we identified the ionotropic receptors IR25a, IR8a and IR93a, and several divergent IR candidates to be expressed in the cyprid antennules. We found one gustatory-like receptor but no odorant receptors, chemosensory or odorant-binding proteins. Apart from chemosensory receptors, we also identified 13 potential mechanosensory genes represented by several transient receptor potential channels (TRP) subfamilies. Furthermore, we analyzed changes in expression profiles of IRs and TRPs during the B. improvisus settling process. Several of the sensory genes were differentially expressed during the course of larval settlement. This study gives expanded knowledge about the sensory systems present in barnacles, a taxonomic group for which only limited information about receptors is currently available. It furthermore serves as a starting point for more in depth studies of how sensory signaling affects settling behavior in barnacles with implications for preventing biofouling. © 2019 Abramova et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 5. |
- Abramova, Anna, 1990, et al.
(författare)
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The complex barnacle perfume: identification of waterborne pheromone homologues in Balanus improvisus and their differential expression during settlement
- 2019
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 35:4, s. 416-428
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Tidskriftsartikel (refereegranskat)abstract
- A key question in barnacle biology is the nature of cues that induce gregarious settlement. One of the characterised cues is the waterborne settlement pheromone (WSP). This study aimed to identify WSP homologues in Balanus improvisus and to investigate their expression during settlement. Six WSP homologues were identified, all containing an N-terminal signal peptide, a conserved core region, and a variable C-terminus comprising several -GR- and -HDDH- motifs. The B. improvisus WSP homologues were expressed in all settlement stages but showed different expression patterns. The homologue most similar to the B. amphitrite WSP was the most abundant and was constantly expressed during settlement. In contrast, several of the other WSP homologues showed the greatest expression in the juvenile stage. The presence of several WSP homologues suggests the existence of a pheromone mix, where con-specificity might be determined by a combination of sequence characteristics and the concentration of the individual components.
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| 6. |
- Adrian-Kalchhauser, Irene, et al.
(författare)
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The mitochondrial genome sequences of the round goby and the sand goby reveal patterns of recent evolution in gobiid fish
- 2017
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Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Vertebrate mitochondrial genomes are optimized for fast replication and low cost of RNA expression. Accordingly, they are devoid of introns, are transcribed as polycistrons and contain very little intergenic sequences. Usually, vertebrate mitochondrial genomes measure between 16.5 and 17 kilobases (kb). Results During genome sequencing projects for two novel vertebrate models, the invasive round goby and the sand goby, we found that the sand goby genome is exceptionally small (16.4 kb), while the mitochondrial genome of the round goby is much larger than expected for a vertebrate. It is 19 kb in size and is thus one of the largest fish and even vertebrate mitochondrial genomes known to date. The expansion is attributable to a sequence insertion downstream of the putative transcriptional start site. This insertion carries traces of repeats from the control region, but is mostly novel. To get more information about this phenomenon, we gathered all available mitochondrial genomes of Gobiidae and of nine gobioid species, performed phylogenetic analyses, analysed gene arrangements, and compared gobiid mitochondrial genome sizes, ecological information and other species characteristics with respect to the mitochondrial phylogeny. This allowed us amongst others to identify a unique arrangement of tRNAs among Ponto-Caspian gobies. Conclusions Our results indicate that the round goby mitochondrial genome may contain novel features. Since mitochondrial genome organisation is tightly linked to energy metabolism, these features may be linked to its invasion success. Also, the unique tRNA arrangement among Ponto-Caspian gobies may be helpful in studying the evolution of this highly adaptive and invasive species group. Finally, we find that the phylogeny of gobiids can be further refined by the use of longer stretches of linked DNA sequence.
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| 7. |
- Adrian-Kalchhauser, I., et al.
(författare)
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The round goby genome provides insights into mechanisms that may facilitate biological invasions
- 2020
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Ingår i: BMC Biology. - : Springer Science and Business Media LLC. - 1741-7007. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background The invasive benthic round goby (Neogobius melanostomus) is the most successful temperate invasive fish and has spread in aquatic ecosystems on both sides of the Atlantic. Invasive species constitute powerful in situ experimental systems to study fast adaptation and directional selection on short ecological timescales and present promising case studies to understand factors involved the impressive ability of some species to colonize novel environments. We seize the unique opportunity presented by the round goby invasion to study genomic substrates potentially involved in colonization success. Results We report a highly contiguous long-read-based genome and analyze gene families that we hypothesize to relate to the ability of these fish to deal with novel environments. The analyses provide novel insights from the large evolutionary scale to the small species-specific scale. We describe expansions in specific cytochrome P450 enzymes, a remarkably diverse innate immune system, an ancient duplication in red light vision accompanied by red skin fluorescence, evolutionary patterns of epigenetic regulators, and the presence of osmoregulatory genes that may have contributed to the round goby's capacity to invade cold and salty waters. A recurring theme across all analyzed gene families is gene expansions. Conclusions The expanded innate immune system of round goby may potentially contribute to its ability to colonize novel areas. Since other gene families also feature copy number expansions in the round goby, and since other Gobiidae also feature fascinating environmental adaptations and are excellent colonizers, further long-read genome approaches across the goby family may reveal whether gene copy number expansions are more generally related to the ability to conquer new habitats in Gobiidae or in fish.
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| 8. |
- Alm Rosenblad, Magnus, 1957
(författare)
-
Computational identification of RNA and protein components from the Signal Recognition Particle
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Problem. The signal recognition particle (SRP) is a ribonucleoprotein particle that targets proteins to the endoplasmic reticulum in eukaryotes, to the plasma membrane in Archaea and Bacteria and to the thylakoid membrane in chloroplasts of photosynthetic organisms. It has one RNA component and 1 6 proteins. The eukaryotic particle is composed of one S domain responsible for signal recognition and one Alu domain responsible for translation elongation arrest. In many phylogenetic groups the SRP is not characterized. Therefore, we aim to identify SRP component genes by computational screening of a large number of organisms where genomic information is available. Methods. For the protein gene identification, we relied on methods based on primary sequence alignments (BLAST, FASTA), profile searches (PSI-BLAST, HMMER, Profilescan), and secondary structure prediction (PSI-Pred). The main focus in this work is the identification of SRP RNA. It is highly diverse in its structure and has a low primary sequence conservation between different phylogenetic groups. As a consequence, standard sequence analysis tools, such as BLAST, are not useful. We have developed a tool for the identification of SRP RNA (SRPscan) using algorithms for pattern matching and covariance analysis of secondary structures.Results. We have carried out an extensive inventory of SRP components by screening available genomic sequences. As a result we have identified a large number of novel genes. The protein and RNA sequences are presented in the SRP database (SRPDB). We have identified full or partial SRP RNA genes in virtually all organisms where genomic sequences of nearly full genome coverage are available, and the findings have led to a proposal of a new nomenclature for SRP RNA.In an analysis of bacterial RNAs we found species with an unusual URRC tetraloop and we identified an RNA from deeply branching gram-negative bacterium Thermotoga that is of the gram-positive Bacillus type. It was previously believed that chloroplasts do not have an SRP RNA. However, we have shown that chloroplast genomes of red algae or red algal origin, as well as some green algae, encode a bacterial type SRP RNA.Eukaryotic SRP RNAs are highly divergent in their structures, mainly in the Alu domain. Based on an analysis of fungal RNAs we were able to present a novel secondary structure model of these RNAs. Analysis of eukaryotic RNAs includes a number of unexpected findings. In the fungal groups Basidiomycota and Zygomycota the SRP RNA has an Alu domain that conforms to the standard mammalian SRP RNA structure. The external loop of helix 8 is a tetraloop as a rule, but in several protists this sequence is a pentaloop. Finally, we suggest that some eukaryal species like Microsporidia might lack an SRP Alu domain.Conclusion. By computational screening of genomic sequences we have identified a large number of novel SRP RNA and proteins components. The results of these studies provide significant insights into the structure, function and phylogeny of the SRP.
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| 9. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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Detection of signal recognition particle (SRP) RNAs in the nuclear ribosomal internal transcribed spacer 1 (ITS1) of three lineages of ectomycorrhizal fungi (Agaricomycetes, Basidiomycota)
- 2016
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Ingår i: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; 13, s. 21-33
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Tidskriftsartikel (refereegranskat)abstract
- During a routine scan for Signal Recognition Particle (SRP) RNAs in eukaryotic sequences, we surprisingly found in silico evidence in GenBank for a 265-base long SRP RNA sequence in the ITS1 region of a total of 11 fully identified species in three ectomycorrhizal genera of the Basidiomycota (Fungi): Astraeus, Russula, and Lactarius. To rule out sequence artifacts, one specimen from a species indicated to have the SRP RNA-containing ITS region in each of these genera was ordered and re-sequenced. Sequences identical to the corresponding GenBank entries were recovered, or in the case of a non-original but conspecific specimen differed by three bases, showing that these species indeed have an SRP RNA sequence incorporated into their ITS1 region. Other than the ribosomal genes, this is the first known case of non-coding RNAs in the eukaryotic ITS region, and it may assist in the examination of other types of insertions in fungal genomes.
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| 10. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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Evidence for further non-coding RNA genes in the fungal rDNA region
- 2022
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Ingår i: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; :90, s. 203-213
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Tidskriftsartikel (refereegranskat)abstract
- Non-coding RNA (ncRNA) genes play important, but incompletely understood, roles in various cellular processes, notably translation and gene regulation. A recent report on the detection of the ncRNA Signal Recognition Particle gene in the nuclear ribosomal internal transcribed spacer region of several species of three genera of ectomycorrhizal basidiomycetes prompted a more thorough bioinformatics search for additional ncRNA genes in the full fungal ribosomal operon. This study reports on the detection of three ncRNA genes hitherto not known from the fungal ribosomal region: nuclear RNase P RNA, RNase MRP RNA, and a possible snoRNA U14 in a total of five species ofAuricularia and Inocybe. We verified their presence through resequencing of independent specimens. Two completedAuricularia genomes were found to lack these ncRNAs elsewhere than in the ribosomal operon, suggesting that these are functional genes. It seems clear that ncRNA genes play a larger role in fungal ribosomal genetics than hitherto thought.
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| 11. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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Genomic Characterization of the Barnacle Balanus improvisus Reveals Extreme Nucleotide Diversity in Coding Regions
- 2021
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Ingår i: Marine Biotechnology. - : Springer Science and Business Media LLC. - 1436-2228 .- 1436-2236. ; 23, s. 402-416
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Tidskriftsartikel (refereegranskat)abstract
- Barnacles are key marine crustaceans in several habitats, and they constitute a common practical problem by causing biofouling on man-made marine constructions and ships. Despite causing considerable ecological and economic impacts, there is a surprising void of basic genomic knowledge, and a barnacle reference genome is lacking. We here set out to characterize the genome of the baybarnacle Balanus improvisus (= Amphibalanus improvisus) based on short-read whole-genome sequencing and experimental genome size estimation. We show both experimentally (DNA staining and flow cytometry) and computationally (k-mer analysis) that B. improvisus has a haploid genome size of ~ 740 Mbp. A pilot genome assembly rendered a total assembly size of ~ 600 Mbp and was highly fragmented with an N50 of only 2.2 kbp. Further assembly-based and assembly-free analyses revealed that the very limited assembly contiguity is due to the B. improvisus genome having an extremely high nucleotide diversity (π) in coding regions (average π ≈ 5% and average π in fourfold degenerate sites ≈ 20%), and an overall high repeat content (at least 40%). We also report on high variation in the α-octopamine receptor OctA (average π = 3.6%), which might increase the risk that barnacle populations evolve resistance toward antifouling agents. The genomic features described here can help in planning for a future high-quality reference genome, which is urgently needed to properly explore and understand proteins of interest in barnacle biology and marine biotechnology and for developing better antifouling strategies. © 2021, The Author(s).
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| 12. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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Identification and comparative analysis of components from the signal recognition particle in protozoa and fungi.
- 2004
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Ingår i: BMC genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The signal recognition particle (SRP) is a ribonucleoprotein complex responsible for targeting proteins to the ER membrane. The SRP of metazoans is well characterized and composed of an RNA molecule and six polypeptides. The particle is organized into the S and Alu domains. The Alu domain has a translational arrest function and consists of the SRP9 and SRP14 proteins bound to the terminal regions of the SRP RNA. So far, our understanding of the SRP and its evolution in lower eukaryotes such as protozoa and yeasts has been limited. However, genome sequences of such organisms have recently become available, and we have now analyzed this information with respect to genes encoding SRP components. RESULTS: A number of SRP RNA and SRP protein genes were identified by an analysis of genomes of protozoa and fungi. The sequences and secondary structures of the Alu portion of the RNA were found to be highly variable. Furthermore, proteins SRP9/14 appeared to be absent in certain species. Comparative analysis of the SRP RNAs from different Saccharomyces species resulted in models which contain features shared between all SRP RNAs, but also a new secondary structure element in SRP RNA helix 5. Protein SRP21, previously thought to be present only in Saccharomyces, was shown to be a constituent of additional fungal genomes. Furthermore, SRP21 was found to be related to metazoan and plant SRP9, suggesting that the two proteins are functionally related. CONCLUSIONS: Analysis of a number of not previously annotated SRP components show that the SRP Alu domain is subject to a more rapid evolution than the other parts of the molecule. For instance, the RNA portion is highly variable and the protein SRP9 seems to have evolved into the SRP21 protein in fungi. In addition, we identified a secondary structure element in the Saccharomyces RNA that has been inserted close to the Alu region. Together, these results provide important clues as to the structure, function and evolution of SRP.
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| 13. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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Identification of chloroplast signal recognition particle RNA genes.
- 2004
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Ingår i: Plant & cell physiology. - : Oxford University Press (OUP). - 0032-0781 .- 1471-9053. ; 45:11, s. 1633-9
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Tidskriftsartikel (refereegranskat)abstract
- The signal recognition particle (SRP) is a ribonucleoprotein complex responsible for targeting proteins to the ER membrane in eukaryotes, the plasma membrane in bacteria and the thylakoid membrane in chloroplasts. In higher plants two different SRP-dependent mechanisms have been identified: one post-translational for proteins imported to the chloroplast and one co-translational for proteins encoded by the plastid genome. The post-translational chloroplast SRP (cpSRP) consists of the protein subunits cpSRP54 and cpSRP43. An RNA component has not been identified and does not seem to be required for the post-translational cpSRP. The co-translational mechanism is known to involve cpSRP54, but an RNA component has not yet been identified. Several chloroplast genomes have been sequenced recently, making a phylogenetically broad computational search for cpSRP RNA possible. We have analysed chloroplast genomes from 27 organisms. In higher plant chloroplasts, no SRP RNA genes were identified. However, eight plastids from red algae and Chlorophyta were found to contain an SRP RNA gene. These results suggest that SRP RNA forms a complex in these plastids with cpSRP54, reminiscent of the eubacterial SRP.
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| 14. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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Inventory and analysis of the protein subunits of the ribonucleases P and MRP provides further evidence of homology between the yeast and human enzymes.
- 2006
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Ingår i: Nucleic acids research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 34:18, s. 5145-56
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Tidskriftsartikel (refereegranskat)abstract
- The RNases P and MRP are involved in tRNA and rRNA processing, respectively. Both enzymes in eukaryotes are composed of an RNA molecule and 9-12 protein subunits. Most of the protein subunits are shared between RNases P and MRP. We have here performed a computational analysis of the protein subunits in a broad range of eukaryotic organisms using profile-based searches and phylogenetic methods. A number of novel homologues were identified, giving rise to a more complete inventory of RNase P/MRP proteins. We present evidence of a relationship between fungal Pop8 and the protein subunit families Rpp14/Pop5 as well as between fungal Pop6 and metazoan Rpp25. These relationships further emphasize a structural and functional similarity between the yeast and human P/MRP complexes. We have also identified novel P and MRP RNAs and analysis of all available sequences revealed a K-turn motif in a large number of these RNAs. We suggest that this motif is a binding site for the Pop3/Rpp38 proteins and we discuss other structural features of the RNA subunit and possible relationships to the protein subunit repertoire.
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| 15. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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Kinship in the SRP RNA family
- 2009
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Ingår i: RNA Biology. - 1547-6286. ; 6:5
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Tidskriftsartikel (refereegranskat)abstract
- The signal recognition particle (SRP) is a ribonucleoprotein complex which participates in the targeting of protein to cellular membranes. The RNA component of the SRP has been found in all domains of life, but the size of the molecule and the number of RNA secondary structure elements vary considerably between the different phylogenetic groups. We continued our efforts to identify new SRP RNAs, compare their sequences, discover new secondary structure elements, conserved motifs, and other properties. We found additional proof for the variability in the apical loop of helix 8, and we identified several bacteria which lack all of their SRP components. Based on the distribution of SRP RNA features within the taxonomy, we suggest seven alignment groups: Bacteria with a small (4.5S) SRP RNA, Bacteria with a large (6S) SRP RNA, Archaea, Fungi (Ascomycota), Metazoa group, Protozoa group, and Plants. The proposed divisions improve the prediction of more distantly related SRP RNAs and provide a more inclusive representation of the SRP RNA family. Updates of the Rfam SRP RNA sequence collection are expected to benefit from the suggested groupings.
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| 16. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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SRPDB: Signal Recognition Particle Database
- 2003
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Ingår i: Nucleic Acids Research. - 0305-1048. ; 31:1, s. 363-4
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Tidskriftsartikel (refereegranskat)abstract
- The Signal Recognition Particle Database (SRPDB) at http://psyche.uthct.edu/dbs/SRPDB/SRPDB.html and http://bio.lundberg.gu.se/dbs/SRPDB/SRPDB.html assists in the better understanding of the structure and function of the signal recognition particle (SRP), a ribonucleoprotein complex that recognizes signal sequences as they emerge from the ribosome. SRPDB provides alphabetically and phylogenetically ordered lists of SRP RNA and SRP protein sequences. The SRP RNA alignment emphasizes base pairs supported by comparative sequence analysis to derive accurate SRP RNA secondary structures for each species. This release includes a total of 181 SRP RNA sequences, 7 protein SRP9, 11 SRP14, 31 SRP19, 113 SRP54 (Ffh), 9 SRP68 and 12 SRP72 sequences. There are 44 new sequences of the SRP receptor alpha subunit and its FtsY homolog (a total of 99 entries). Additional data are provided for polypeptides with established or potential roles in SRP-mediated protein targeting, such as the beta subunit of SRP receptor, Flhf, Hbsu and cpSRP43. Also available are motifs for the identification of new SRP RNA sequences, 2D representations, three-dimensional models in PDB format, and links to the high-resolution structures of several SRP components. New to this version of SRPDB is the introduction of a relational database system and a SRP RNA prediction server (SRP-Scan) which allows the identification of SRP RNAs within genome sequences and also generates secondary structure diagrams.
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| 17. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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Structural diversity of signal recognition particle RNAs in plastids
- 2013
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Ingår i: Plant Signalling & Behavior. - : Informa UK Limited. - 1559-2316 .- 1559-2324. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- One of the pathways for protein targeting to the plasma membrane in bacteria utilizes the co-translationally acting signal recognition particle (SRP), a universally conserved ribonucleoprotein complex consisting of a 54 kDa protein and a functional RNA. An interesting exception is the higher plant chloroplast SRP, which lacks the otherwise essential RNA component. Furthermore, green plant chloroplasts have an additional post-translational SRP-dependent transport system in which the chloroplast-specific cpSRP43 protein binds to imported substrate proteins and to the conserved 54 kDa SRP subunit (cpSRP54). While homologs to the bacterial SRP protein and RNA component previously have been identified in genome sequences of red algae and diatoms, a recent study investigated the evolution of the green plant SRP system.1 Analysis of hundreds of plastid and nuclear genomes showed a surprising pattern of multiple losses of the plastid SRP RNA during evolution and a widespread presence in all non-spermatophyte plants and green algae. Contrary to expectations, all green organisms that have an identified cpSRP RNA also contain a cpSRP43. Notably, the structure of the plastid SRP RNAs is much more diverse than that of bacterial SRP RNAs. The apical GNRA tetraloop is only conserved in organisms of the red lineage and basal organisms of the green lineage, whereas further chloroplast SRP RNAs are characterized by atypical, mostly enlarged apical loops.
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| 18. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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The enigmatic RNase MRP of kinetoplastids
- 2021
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Ingår i: Rna Biology. - : Informa UK Limited. - 1547-6286 .- 1555-8584. ; 18:Supplement 1, s. 139-147
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Tidskriftsartikel (refereegranskat)abstract
- The ribonucleoprotein RNase MRP is responsible for the processing of ribosomal RNA precursors. It is found in virtually all eukaryotes that have been examined. In the Euglenozoa, including the genera Euglena, Diplonema and kinetoplastids, MRP RNA and protein subunits have so far escaped detection using bioinformatic methods. However, we now demonstrate that the RNA component is widespread among the Euglenozoa and that these RNAs have secondary structures that conform to the structure of all other phylogenetic groups. In Euglena, we identified the same set of P/MRP protein subunits as in many other protists. However, we failed to identify any of these proteins in the kinetoplastids. This finding poses interesting questions regarding the structure and function of RNase MRP in these species.
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| 19. |
- Alm Rosenblad, Magnus, 1957, et al.
(författare)
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The Signal Recognition Particle of the diplomonad Giardia lacks the Alu domain responsible for translational arrest
- 2008
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Ingår i: RNA Society Meeting 2008.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- One of the most conserved cellular processes is the co-translational targeting of secretory and membrane proteins to the Sec translocon by the Signal Recognition Particle (SRP). This ribonucleoprotein particle consists in most eukaryotes of one RNA molecule and six proteins, and may be divided into two domains with distinct functions: the "S domain", which is most conserved, binds to the nascent peptide chain as it emerges from the exit tunnel of the ribosome, and the "Alu domain" which has a translation-regulatory function and causes an elongation arrest of the peptide chain. Of the six proteins only two is part of the Alu domain: SRP9/14.
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| 20. |
- Bengtsson, Johan, 1985, et al.
(författare)
-
Metaxa: Automated detection and discrimination among ribosomal small subunit (12S/16S/18S) sequences of archaea, bacteria, eukaryotes, mitochondria, and chloroplasts
- 2011
-
Ingår i: SocBiN Bioinformatics Conference, Helsinki, Finland, 2011.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The ribosomal small subunit (SSU) rRNA gene has emerged as an important genetic marker for taxonomic identification in environmental sequencing datasets. However, the gene is not only present in the nuclear genome of eukaryotes and the core genome of prokaryotes, but also in the mitochondria and chloroplasts of eukaryotes. The SSU genes in the core genome, mitochondria and chloroplast are conceptually paralogous and should in most situations not be aligned and analyzed jointly, e.g. when estimating species diversity. Identifying the origin of SSU sequences in complex sequence datasets is a time-consuming and largely manual undertaking. To ease this situation, we have created Metaxa, an automated software tool to extract full-length and partial SSU sequences from larger sequence datasets and assign them to an archaeal, bacte- rial, nuclear eukaryote, mitochondrial, or chloroplast origin. Metaxa very efficiently detects SSU sequences from fragments as short as 200 base pairs, and correctly classifies 97% of the identified genes at read lengths typically obtained from pyrosequencing. In addition, Metaxa shows a false positive rate of 0.00012% when run on random DNA fragments, showing the robustness of the method. We believe that this tool will be useful in microbial and evolutionary ecology as well as in metagenomics.
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| 21. |
- Bengtsson-Palme, Johan, 1985, et al.
(författare)
-
Metagenomics reveals that detoxification systems are underrepresented in marine bacterial communities
- 2014
-
Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 15:749
-
Tidskriftsartikel (refereegranskat)abstract
- Background Environmental shotgun sequencing (metagenomics) provides a new way to study communities in microbial ecology. We here use sequence data from the Global Ocean Sampling (GOS) expedition to investigate toxicant selection pressures revealed by the presence of detoxification genes in marine bacteria. To capture a broad range of potential toxicants we selected detoxification protein families representing systems protecting microorganisms from a variety of stressors, such as metals, organic compounds, antibiotics and oxygen radicals. Results Using a bioinformatics procedure based on comparative analysis to finished bacterial genomes we found that the amount of detoxification genes present in marine microorganisms seems surprisingly small. The underrepresentation is particularly evident for toxicant transporters and proteins involved in detoxifying metals. Exceptions are enzymes involved in oxidative stress defense where peroxidase enzymes are more abundant in marine bacteria compared to bacteria in general. In contrast, catalases are almost completely absent from the open ocean environment, suggesting that peroxidases and peroxiredoxins constitute a core line of defense against reactive oxygen species (ROS) in the marine milieu. Conclusions We found no indication that detoxification systems would be generally more abundant close to the coast compared to the open ocean. On the contrary, for several of the protein families that displayed a significant geographical distribution, like peroxidase, penicillin binding transpeptidase and divalent ion transport protein, the open ocean samples showed the highest abundance. Along the same lines, the abundance of most detoxification proteins did not increase with estimated pollution. The low level of detoxification systems in marine bacteria indicate that the majority of marine bacteria have a low capacity to adapt to increased pollution. Our study exemplifies the use of metagenomics data in ecotoxicology, and in particular how anthropogenic consequences on life in the sea can be examined.
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| 22. |
- Bengtsson-Palme, Johan, 1985, et al.
(författare)
-
Metaxa: a software tool for automated detection and discrimination among ribosomal small subunit (12S/16S/18S) sequences of archaea, bacteria, eukaryotes, mitochondria, and chloroplasts in metagenomes and environmental sequencing datasets
- 2011
-
Ingår i: Antonie van Leeuwenhoek: international journal of general and molecular microbiology. - : Springer Science and Business Media LLC. - 0003-6072 .- 1572-9699. ; 100:3, s. 471-475
-
Tidskriftsartikel (refereegranskat)abstract
- The ribosomal small subunit (SSU) rRNA gene has emerged as an important genetic marker for taxonomic identification in environmental sequencing datasets. In addition to being present in the nucleus of eukaryotes and the core genome of prokaryotes, the gene is also found in the mitochondria of eukaryotes and in the chloroplasts of photosynthetic eukaryotes. These three sets of genes are conceptually paralogous and should in most situations not be aligned and analyzed jointly. To identify the origin of SSU sequences in complex sequence datasets has hitherto been a time-consuming and largely manual undertaking. However, the present study introduces Metaxa (http://microbiology.se/software/metaxa/), an automated software tool to extract full-length and partial SSU sequences from larger sequence datasets and assign them to an archaeal, bacterial, nuclear eukaryote, mitochondrial, or chloroplast origin. Using data from reference databases and from full-length organelle and organism genomes, we show that Metaxa detects and scores SSU sequences for origin with very low proportions of false positives and negatives. We believe that this tool will be useful in microbial and evolutionary ecology as well as in metagenomics.
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| 23. |
- Blomberg, Anders, 1956, et al.
(författare)
-
Establishing the barnacle Balanus improvisus as a potent invertebrate monitoring system in marine ecotoxicogenomics
- 2009
-
Ingår i: SETAC Europe 19th Annual Meeting Abstract Book, Göteborg 31 May - 4 June, 2009.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There is a need for potent invertebrate systems for assessing the impacts of environmental contaminants on marine ecosystems. Balanus improvisus, a marine athropod, has a number of promising characteristics that make it a good candidate in such efforts. We have conducted sequencing of a cDNA library from the cyprid larval stage and identified several detoxification systems as well as novel B. improvisus specific genes. To investigate the toxicological gene expression response in this organism, we performed a short-term exposure experiment of the cyprid larvae to two different biofouling substances. From a natural population of B. improvisus, 300 - 1000 cyprids were treated for 23 hours with 390nM CuO or with two different concentrations (10nM or 10μM) of meditomidine. Protein expression changes were studied by 2D-PAGE analysis after DIGE labelling. For gene expression analysis by DNA miroarrays total RNA was extracted and used for cDNA and cRNA/aRNA templates. Roughly 2000 B. improvisus genes were studied represented by 3000 different probes on the arrays (each in duplicates). Candidate genes were confirmed by qPCR. A number of protein expression changes were detected on the 2D gels as a result of the different treatments. Interestingly, the response to the different treatments clearly formed distinct groups in principle component analysis. The DNA microarray analysis revealed several genes as toxicity indicators, e.g. various heat shock proteins, some proteases and factors involved in regulatory processes (transcription factors). Our data indicate that B. improvisus may serve as a tool to evaluate the impacts of marine pollution, and thus to fill the niche as an important invertebrate marine model organism for ecotoxicology and environmental genomics.
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| 24. |
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| 25. |
- Davila Lopez, Marcela, et al.
(författare)
-
Computational screen for spliceosomal RNA genes aids in defining the phylogenetic distribution of the major and minor spliceosomal components
- 2008
-
Ingår i: RNA Society Meeting 2008.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An essential step of gene expression is the removal of non-coding sequences (introns) from the pre-mRNA and the ligation of coding sequences (exons) to form the mature RNA (mRNA). It is known that the pre-mRNA splicing occurs by two sequential trans-esterification reactions and is catalyzed by a multicomponent complex, the spliceosome. Its assembly involves five small nuclear ribonucleoprotein particles (snRNPs) as well as an array of protein factors, which are determined by the class of intron to be spliced1. To date, two intron classes are known, U2- and U12-type introns. The U2-dependent spliceosome (panel a) is formed by the interaction of the U1, U2, U4/U6 and U5 snRNPs and numerous non-snRNP proteins with the pre-mRNA. The U12-dependent spliceosome (also referred to as the minor spliceosome, panel b), in contrast, consists of the U11, U12, U4atac/U6atac and U5 snRNPs with an unknown number of non-snRNP proteins. Thus, of the main spliceosomal subunits, only the U5 snRNA is common to both spliceosomes2.
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| 26. |
- Davila Lopez, Marcela, et al.
(författare)
-
Conserved and variable domains of RNase MRP RNA
- 2009
-
Ingår i: RNA Biology. - 1547-6286. ; 6:3, s. 208-221
-
Tidskriftsartikel (refereegranskat)abstract
- Ribonuclease MRP is a eukaryotic ribonucleoprotein complex consisting of one RNA molecule and 7-10 protein subunits. One important function of MRP is to catalyze an endonucleolytic cleavage during processing of rRNA precursors. RNase MRP is evolutionary related to RNase P which is critical for tRNA processing. A large number of MRP RNA sequences that now are available have been used to identify conserved primary and secondary structure features of the molecule. MRP RNA has structural features in common with P RNA such as a conserved catalytic core, but it also has unique features and is characterized by a domain highly variable between species. Information regarding primary and secondary structure features is of interest not only in basic studies of the function of MRP RNA, but also because mutations in the RNA give rise to human genetic diseases such as cartilage-hair hypoplasia.
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| 27. |
- Dumesic, Phillip A, et al.
(författare)
-
Noncanoncial signal recognition particle RNAs in a major eukaryotic phylum revealed by purification of SRP from the human pathogen Cryptococcus neoformans.
- 2015
-
Ingår i: Nucleic acids research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 43:18, s. 9017-9027
-
Tidskriftsartikel (refereegranskat)abstract
- Despite conservation of the signal recognition particle (SRP) from bacteria to man, computational approaches have failed to identify SRP components from genomes of many lower eukaryotes, raising the possibility that they have been lost or altered in those lineages. We report purification and analysis of SRP in the human pathogen Cryptococcus neoformans, providing the first description of SRP in basidiomycetous yeast. The C. neoformans SRP RNA displays a predicted structure in which the universally conserved helix 8 contains an unprecedented stem-loop insertion. Guided by this sequence, we computationally identified 152 SRP RNAs throughout the phylum Basidiomycota. This analysis revealed additional helix 8 alterations including single and double stem-loop insertions as well as loop diminutions affecting RNA structural elements that are otherwise conserved from bacteria to man. Strikingly, these SRP RNA features in Basidiomycota are accompanied by phylum-specific alterations in the RNA-binding domain of Srp54, the SRP protein subunit that directly interacts with helix 8. Our findings reveal unexpected fungal SRP diversity and suggest coevolution of the two most conserved SRP features-SRP RNA helix 8 and Srp54-in basidiomycetes. Because members of this phylum include important human and plant pathogens, these noncanonical features provide new targets for antifungal compound development.
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| 28. |
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| 29. |
- Jansson, Kristina, 1970, et al.
(författare)
-
Evolutionary loss of 8-oxo-G repair components among eukaryotes
- 2010
-
Ingår i: Genome Integrity. - 2041-9414. ; 1
-
Tidskriftsartikel (refereegranskat)abstract
- Background We have examined the phylogenetic pattern among eukaryotes of homologues of the E. coli 7,8-dihydro-8-oxoguanine (8-oxo-G) repair enzymes MutY, MutM, and MutT. Results: These DNA repair enzymes are present in all large phylogenetic groups, with MutM homologues being the most universally conserved. All chordates and echinoderms were found to possess all three 8-oxo-G repair components. Likewise, the red and green algae examined have all three repair enzymes, while all land-living plants have MutY and MutM homologues, but lack MutT. However, for some phyla, e.g. protostomes, a more patchy distribution was found. Nematodes provide a striking example, where Caenorhabditis is the only identified example of an organism group having none of the three repair enzymes, while the genome of another nematode, Trichinella spiralis, instead encodes all three. The most complex distribution exists in fungi, where many different patterns of retention or loss of the three repair components are found. In addition, we found sequence insertions near or within the catalytic sites of MutY, MutM, and MutT to be present in some subgroups of Ascomycetes. Conclusion The 8-oxo-G repair enzymes are ancient in origin, and loss of individual 8 oxo G repair components at several distinct points in evolution appears to be the most likely explanation for the phylogenetic pattern among eukaryotes.
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| 30. |
- Lind, Ulrika, et al.
(författare)
-
Octopamine receptors from the barnacle balanus improvisus are activated by the alpha2-adrenoceptor agonist medetomidine.
- 2010
-
Ingår i: Molecular pharmacology. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0111 .- 0026-895X. ; 78:2, s. 237-48
-
Tidskriftsartikel (refereegranskat)abstract
- G protein-coupled octopamine receptors of insects and other invertebrates represent counterparts of adrenoceptors in vertebrate animals. The alpha(2)-adrenoceptor agonist medetomidine, which is in clinical use as a veterinary sedative agent, was discovered to inhibit the settling process of barnacles, an important step in the ontogeny of this crustacean species. Settling of barnacles onto ship hulls leads to biofouling that has many harmful practical consequences, and medetomidine is currently under development as a novel type of antifouling agent. We now report that medetomidine induces hyperactivity in the barnacle larvae to disrupt the settling process. To identify the molecular targets of medetomidine, we cloned five octopamine receptors from the barnacle Balanus improvisus. We show by phylogenetic analyses that one receptor (BiOctalpha) belongs to the alpha-adrenoceptor-like subfamily, and the other four (BiOctbeta-R1, BiOctbeta-R2, BiOctbeta-R3, and BiOctbeta-R4) belong to the beta-adrenoceptor-like octopamine receptor subfamily. Phylogenetic analyses also indicated that B. improvisus has a different repertoire of beta-adrenoceptor-like octopamine receptors than insects. When expressed in CHO cells, the cloned receptors were activated by both octopamine and medetomidine, resulting in increased intracellular cAMP or calcium levels. Tyramine activated the receptors but with much lesser potency than octopamine. A hypothesis for receptor discrimination between tyramine and octopamine was generated from a homology three-dimensional model. The characterization of B. improvisus octopamine receptors is important for a better functional understanding of these receptors in crustaceans as well as for practical applications in development of environmentally sustainable antifouling agents.
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| 31. |
- Nunez, Joaquin C B, et al.
(författare)
-
Ecological load and balancing selection in circumboreal barnacles.
- 2021
-
Ingår i: Molecular biology and evolution. - : Oxford University Press (OUP). - 1537-1719. ; 38:2, s. 676-685
-
Tidskriftsartikel (refereegranskat)abstract
- Acorn barnacle adults experience environmental heterogeneity at various spatial scales of their circumboreal habitat, raising the question of how adaptation to high environmental variability is maintained in the face of strong juvenile dispersal and mortality. Here we show that 4% of genes in the barnacle genome experience balancing selection across the entire range of the species. Many of these genes harbor mutations maintained across 2 million years of evolution between the Pacific and Atlantic oceans. These genes are involved in ion regulation, pain reception, and heat tolerance, functions which are essential in highly variable ecosystems. The data also reveal complex population structure within and between basins, driven by the trans-Arctic interchange and the last glaciation. Divergence between Atlantic and Pacific populations is high, foreshadowing the onset of allopatric speciation, and suggesting that balancing selection is strong enough to maintain functional variation for millions of years in the face of complex demography.
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| 32. |
- Nunez, J. C. B., et al.
(författare)
-
Footprints of natural selection at the mannose-6-phosphate isomerase locus in barnacles
- 2020
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 117:10, s. 5376-5385
-
Tidskriftsartikel (refereegranskat)abstract
- The mannose-6-phosphate isomerase (Mpi) locus in Semibalanus balanoides has been studied as a candidate gene for balancing selection for more than two decades. Previous work has shown that Mpi allozyme genotypes (fast and slow) have different fre-quencies across Atlantic intertidal zones due to selection on post-settlement survival (i.e., allele zonation). We present the complete gene sequence of the Mpi locus and quantify nucleotide polymor-phism in S. balanoides, as well as divergence to its sister taxon Semibalanus cariosus. We show that the slow allozyme contains a derived charge-altering amino acid polymorphism, and both allo-zyme classes correspond to two haplogroups with multiple internal haplotypes. The locus shows several footprints of balancing selec-tion around the fast/slow site: an enrichment of positive Tajima's D for nonsynonymous mutations, an excess of polymorphism, and a spike in the levels of silent polymorphism relative to silent diver-gence, as well as a site frequency spectrum enriched for midfre-quency mutations. We observe other departures from neutrality across the locus in both coding and noncoding regions. These in-clude a nonsynonymous trans-species polymorphism and a recent mutation under selection within the fast haplogroup. The latter suggests ongoing allelic replacement of functionally relevant amino acid variants. Moreover, predicted models of Mpi protein structure provide insight into the functional significance of the putatively selected amino acid polymorphisms. While footprints of selection are widespread across the range of S. balanoides, our data show that intertidal zonation patterns are variable across both spatial and temporal scales. These data provide further evidence for heteroge-neous selection on Mpi.
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| 33. |
- Nunez, J. C. B., et al.
(författare)
-
From tides to nucleotides: Genomic signatures of adaptation to environmental heterogeneity in barnacles
- 2021
-
Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 30:23, s. 6417-6433
-
Tidskriftsartikel (refereegranskat)abstract
- The northern acorn barnacle (Semibalanus balanoides) is a robust system to study the genetic basis of adaptations to highly heterogeneous environments. Adult barnacles may be exposed to highly dissimilar levels of thermal stress depending on where they settle in the intertidal (i.e., closer to the upper or lower tidal boundary). For instance, barnacles near the upper tidal limit experience episodic summer temperatures above recorded heat coma levels. This differential stress at the microhabitat level is also dependent on the aspect of sun exposure. In the present study, we used pool-seq approaches to conduct a genome wide screen for loci responding to intertidal zonation across the North Atlantic basin (Maine, Rhode Island, and Norway). Our analysis discovered 382 genomic regions containing SNPs which are consistently zonated (i.e., SNPs whose frequencies vary depending on their position in the rocky intertidal) across all surveyed habitats. Notably, most zonated SNPs are young and private to the North Atlantic. These regions show high levels of genetic differentiation across ecologically extreme microhabitats concomitant with elevated levels of genetic variation and Tajima's D, suggesting the action of non-neutral processes. Overall, these findings support the hypothesis that spatially heterogeneous selection is a general and repeatable feature for this species, and that natural selection can maintain functional genetic variation in heterogeneous environments.
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| 34. |
- Panova, Marina, 1973, et al.
(författare)
-
Species and gene divergence in Littorina snails detected by array comparative genomic hybridization
- 2014
-
Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 15
-
Tidskriftsartikel (refereegranskat)abstract
- © 2014 Panova et al.; licensee BioMed Central Ltd. Background: Array comparative genomic hybridization (aCGH) is commonly used to screen different types of genetic variation in humans and model species. Here, we performed aCGH using an oligonucleotide gene-expression array for a non-model species, the intertidal snail Littorina saxatilis. First, we tested what types of genetic variation can be detected by this method using direct re-sequencing and comparison to the Littorina genome draft. Secondly, we performed a genome-wide comparison of four closely related Littorina species: L. fabalis, L. compressa, L. arcana and L. saxatilis and of populations of L. saxatilis found in Spain, Britain and Sweden. Finally, we tested whether we could identify genetic variation underlying " Crab" and " Wave" ecotypes of L. saxatilis.Results: We could reliably detect copy number variations, deletions and high sequence divergence (i.e. above 3%), but not single nucleotide polymorphisms. The overall hybridization pattern and number of significantly diverged genes were in close agreement with earlier phylogenetic reconstructions based on single genes. The trichotomy of L. arcana, L. compressa and L. saxatilis could not be resolved and we argue that these divergence events have occurred recently and very close in time. We found evidence for high levels of segmental duplication in the Littorina genome (10% of the transcripts represented on the array and up to 23% of the analyzed genomic fragments); duplicated genes and regions were mostly the same in all analyzed species. Finally, this method discriminated geographically distant populations of L. saxatilis, but we did not detect any significant genome divergence associated with ecotypes of L. saxatilis.Conclusions: The present study provides new information on the sensitivity and the potential use of oligonucleotide arrays for genotyping of non-model organisms. Applying this method to Littorina species yields insights into genome evolution following the recent species radiation and supports earlier single-gene based phylogenies. Genetic differentiation of L. saxatilis ecotypes was not detected in this study, despite pronounced innate phenotypic differences. The reason may be that these differences are due to single-nucleotide polymorphisms.
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| 35. |
- Piccinelli, Paul, 1975, et al.
(författare)
-
Identification and analysis of ribonuclease P and MRP RNA in a broad range of eukaryotes.
- 2005
-
Ingår i: Nucleic acids research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 33:14, s. 4485-95
-
Tidskriftsartikel (refereegranskat)abstract
- RNases P and MRP are ribonucleoprotein complexes involved in tRNA and rRNA processing, respectively. The RNA subunits of these two enzymes are structurally related to each other and play an essential role in the enzymatic reaction. Both of the RNAs have a highly conserved helical region, P4, which is important in the catalytic reaction. We have used a bioinformatics approach based on conserved elements to computationally analyze available genomic sequences of eukaryotic organisms and have identified a large number of novel nuclear RNase P and MRP RNA genes. For MRP RNA for instance, this investigation increases the number of known sequences by a factor of three. We present secondary structure models of many of the predicted RNAs. Although all sequences are able to fold into the consensus secondary structure of P and MRP RNAs, a striking variation in size is observed, ranging from a Nosema locustae MRP RNA of 160 nt to much larger RNAs, e.g. a Plasmodium knowlesi P RNA of 696 nt. The P and MRP RNA genes appear in tandem in some protists, further emphasizing the close evolutionary relationship of these RNAs.
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| 36. |
- Regalia, Marco, et al.
(författare)
-
Prediction of signal recognition particle RNA genes
- 2002
-
Ingår i: Nucleic Acids Research. - 0305-1048. ; 30:15, s. 3368-77
-
Tidskriftsartikel (refereegranskat)abstract
- We describe a method for prediction of genes that encode the RNA component of the signal recognition particle (SRP). A heuristic search for the strongly conserved helix 8 motif of SRP RNA is combined with covariance models that are based on previously known SRP RNA sequences. By screening available genomic sequences we have identified a large number of novel SRP RNA genes and we can account for at least one gene in every genome that has been completely sequenced. Novel bacterial RNAs include that of Thermotoga maritima, which, unlike all other non-gram-positive eubacteria, is predicted to have an Alu domain. We have also found the RNAs of Lactococcus lactis and Staphylococcus to have an unusual UGAC tetraloop in helix 8 instead of the normal GNRA sequence. An investigation of yeast RNAs reveals conserved sequence elements of the Alu domain that aid in the analysis of these RNAs. Analysis of the human genome reveals only two likely genes, both on chromosome 14. Our method for SRP RNA gene prediction is the first convenient tool for this task and should be useful in genome annotation.
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| 37. |
- Sanli, Kemal, et al.
(författare)
-
Metagenomic Sequencing of Marine Periphyton: Taxonomic and Functional Insights into Biofilm Communities
- 2015
-
Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 6:1192
-
Tidskriftsartikel (refereegranskat)abstract
- Periphyton communities are complex phototrophic, multispecies biofilms that develop on surfaces in aquatic environments. These communities harbor a large diversity of organisms comprising viruses, bacteria, algae, fungi, protozoans and metazoans. However, thus far the total biodiversity of periphyton has not been described. In this study, we use metagenomics to characterize periphyton communities from the marine environment of the Swedish west coast. Although we found approximately ten times more eukaryotic rRNA marker gene sequences compared to prokaryotic, the whole metagenome-based similarity searches showed that bacteria constitute the most abundant phyla in these biofilms. We show that marine periphyton encompass a range of heterotrophic and phototrophic organisms. Heterotrophic bacteria, including the majority of proteobacterial clades and Bacteroidetes, and eukaryotic macro-invertebrates were found to dominate periphyton. The phototrophic groups comprise Cyanobacteria and the alpha-proteobacterial genus Roseobacter, followed by different micro- and macro-algae. We also assess the metabolic pathways that predispose these communities to an attached lifestyle. Functional indicators of the biofilm form of life in periphyton involve genes coding for enzymes that catalyze the production and degradation of extracellular polymeric substances, mainly in the form of complex sugars such as starch and glycogen-like meshes together with chitin. Genes for 278 different transporter proteins were detected in the metagenome, constituting the most abundant protein complexes. Finally, genes encoding enzymes that participate in anaerobic pathways, such as denitrification and methanogenesis, were detected suggesting the presence of anaerobic or low-oxygen micro-zones within the biofilms.
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| 38. |
- Sloth Andersen, Ebbe, et al.
(författare)
-
The tmRDB and SRPDB resources.
- 2006
-
Ingår i: Nucleic acids research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 34:Database issue
-
Tidskriftsartikel (refereegranskat)abstract
- Maintained at the University of Texas Health Science Center at Tyler, Texas, the tmRNA database (tmRDB) is accessible at the URL http://psyche.uthct.edu/dbs/tmRDB/tmRDB.html with mirror sites located at Auburn University, Auburn, Alabama (http://www.ag.auburn.edu/mirror/tmRDB/) and the Royal Veterinary and Agricultural University, Denmark (http://tmrdb.kvl.dk/). The signal recognition particle database (SRPDB) at http://psyche.uthct.edu/dbs/SRPDB/SRPDB.html is mirrored at http://srpdb.kvl.dk/ and the University of Goteborg (http://bio.lundberg.gu.se/dbs/SRPDB/SRPDB.html). The databases assist in investigations of the tmRNP (a ribonucleoprotein complex which liberates stalled bacterial ribosomes) and the SRP (a particle which recognizes signal sequences and directs secretory proteins to cell membranes). The curated tmRNA and SRP RNA alignments consider base pairs supported by comparative sequence analysis. Also shown are alignments of the tmRNA-associated proteins SmpB, ribosomal protein S1, alanyl-tRNA synthetase and Elongation Factor Tu, as well as the SRP proteins SRP9, SRP14, SRP19, SRP21, SRP54 (Ffh), SRP68, SRP72, cpSRP43, Flhf, SRP receptor (alpha) and SRP receptor (beta). All alignments can be easily examined using a new exploratory browser. The databases provide links to high-resolution structures and serve as depositories for structures obtained by molecular modeling.
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| 39. |
- Träger, Chantal, et al.
(författare)
-
Evolution from the Prokaryotic to the Higher Plant Chloroplast Signal Recognition Particle: The Signal Recognition Particle RNA Is Conserved in Plastids of a Wide Range of Photosynthetic Organisms
- 2012
-
Ingår i: The Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 24:12, s. 4819-4836
-
Tidskriftsartikel (refereegranskat)abstract
- The protein targeting signal recognition particle (SRP) pathway in chloroplasts of higher plants has undergone dramatic evolutionary changes. It disposed of its RNA, which is an essential SRP component in bacteria, and uses a unique chloroplast-specific protein cpSRP43. Nevertheless, homologs of the conserved SRP54 and the SRP receptor, FtsY, are present in higher plant chloroplasts. In this study, we analyzed the phylogenetic distribution of SRP components in photosynthetic organisms to elucidate the evolution of the SRP system. We identified conserved plastid SRP RNAs within all nonspermatophyte land plant lineages and in all chlorophyte branches. Furthermore, we show the simultaneous presence of cpSRP43 in these organisms. The function of this novel SRP system was biochemically and structurally characterized in the moss Physcomitrella patens. We show that P. patens chloroplast SRP (cpSRP) RNA binds cpSRP54 but has lost the ability to significantly stimulate the GTPase cycle of SRP54 and FtsY. Furthermore, the crystal structure at 1.8-Å resolution and the nucleotide specificity of P. patens cpFtsY was determined and compared with bacterial FtsY and higher plant chloroplast FtsY. Our data lead to the view that the P. patens cpSRP system occupies an intermediate position in the evolution from bacterial-type SRP to higher plant-type cpSRP system.
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| 40. |
- Töpel, Mats H., 1973, et al.
(författare)
-
The Skeletonema marinoi genome project
- 2015
-
Ingår i: EMBO: Molecular life of Diatoms. 7-10 July, Seattle, USA.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 41. |
- Westram, A. M., et al.
(författare)
-
Do the same genes underlie parallel phenotypic divergence in different Littorina saxatilis populations?
- 2014
-
Ingår i: Molecular Ecology. - : Wiley. - 0962-1083. ; 23:18, s. 4603-4616
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Tidskriftsartikel (refereegranskat)abstract
- Parallel patterns of adaptive divergence and speciation are cited as powerful evidence for the role of selection driving these processes. However, it is often not clear whether parallel phenotypic divergence is underlain by parallel genetic changes. Here, we asked about the genetic basis of parallel divergence in the marine snail Littorina saxatilis, which has repeatedly evolved coexisting ecotypes adapted to either crab predation or wave action. We sequenced the transcriptome of snails of both ecotypes from three distant geographical locations (Spain, Sweden and United Kingdom) and mapped the reads to the L. saxatilis reference genome. We identified genomic regions potentially under divergent selection between ecotypes within each country, using an outlier approach based on FST values calculated per locus. In line with previous studies indicating that gene reuse is generally common, we expected to find extensive sharing of outlier loci due to recent shared ancestry and gene flow between at least two of the locations in our study system. Contrary to our expectations, we found that most outliers were country specific, suggesting that much of the genetic basis of divergence is not shared among locations. However, we did find that more outliers were shared than expected by chance and that differentiation of shared outliers is often generated by the same SNPs. We discuss two mechanisms potentially explaining the limited amount of sharing we observed. First, a polygenic basis of divergent traits might allow for multiple distinct molecular mechanisms generating the same phenotypic patterns. Second, additional, location-specific axes of selection that we did not focus on in this study may produce distinct patterns of genetic divergence within each site.
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| 42. |
- Zhang, H., et al.
(författare)
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Signal Recognition Particle RNA in Dinoflagellates and the Perkinsid Perkinsus marinus
- 2013
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Ingår i: Protist. - : Elsevier BV. - 1434-4610. ; 164:5, s. 748-761
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Tidskriftsartikel (refereegranskat)abstract
- In dinoflagellates and perkinsids, the molecular structure of the protein translocating machinery is unclear. Here, we identified several types of full-length signal recognition particle (SRP) RNA genes from Karenia brevis (dinoflagellate) and Perkinsus marinus (perkinsid). We also identified the four SRP S-domain proteins, but not the two Alu domain proteins, from P. marinus and several dinoflagellates. We mapped both ends of SRP RNA transcripts from K. brevis and P. marinus, and obtained the 3' end from four other dinoflagellates. The lengths of SRP RNA are predicted to be similar to 260-300 nt in dinoflagellates and 280-285 nt in P. marinus. Although these SRP RNA sequences are substantially variable, the predicted structures are similar. The genomic organization of the SRP RNA gene differs among species. In K. brevis, this gene is located downstream of the spliced leader (SL) RNA, either as SL RNA-SRP RNA-tRNA gene tandem repeats, or within a SL RNA-SRP RNA-tRNA-U6-5S rRNA gene cluster. In other dinoflagellates, SRP RNA does not cluster with SL RNA or 5S rRNA genes. The majority of P. marinus SRP RNA genes array as tandem repeats without the above-mentioned small RNA genes. Our results capture a snapshot of a potentially complex evolutionary history of SRP RNA in alveolates. (c) 2013 Elsevier GmbH. All rights reserved.
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| 43. |
- Zwieb, Christian, et al.
(författare)
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A nomenclature for all signal recognition particle RNAs.
- 2005
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Ingår i: RNA (New York, N.Y.). - : Cold Spring Harbor Laboratory. - 1355-8382 .- 1469-9001. ; 11:1, s. 7-13
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Tidskriftsartikel (refereegranskat)abstract
- The signal recognition particle (SRP) is a cytosolic ribonucleoprotein complex that guides secretory proteins to biological membranes in all organisms. The SRP RNA is at the center of the structure and function of the SRP. The comparison of the growing number of SRP RNA sequences provides a rich source for gaining valuable insight into the composition, assembly, and phylogeny of the SRP. In order to assist in the continuation of these studies, we propose an SRP RNA nomenclature applicable to the three divisions of life.
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