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Academic literature on the topic 'Eklf'

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Published: 4 June 2021
Last updated: 20 February 2023

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Journal articles on the topic "Eklf"

1

Hodge, Denise, Elise Coghill, Janelle Keys, Tina Maguire, Belinda Hartmann, Alasdair McDowall, Mitchell Weiss, Sean Grimmond, and Andrew Perkins. "A global role for EKLF in definitive and primitive erythropoiesis." Blood 107, no. 8 (April 15, 2006): 3359–70. http://dx.doi.org/10.1182/blood-2005-07-2888.

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Abstract Erythroid Kruppel-like factor (EKLF, KLF1) plays an important role in definitive erythropoiesis and β-globin gene regulation but failure to rectify lethal fetal anemia upon correction of globin chain imbalance suggested additional critical EKLF target genes. We employed expression profiling of EKLF-null fetal liver and EKLF-null erythroid cell lines containing an inducible EKLF-estrogen receptor (EKLF-ER) fusion construct to search for such targets. An overlapping list of EKLF-regulated genes from the 2 systems included α-hemoglobin stabilizing protein (AHSP), cytoskeletal proteins, hemesynthesis enzymes, transcription factors, and blood group antigens. One EKLF target gene, dematin, which encodes an erythrocyte cytoskeletal protein (band 4.9), contains several phylogenetically conserved consensus CACC motifs predicted to bind EKLF. Chromatin immunoprecipitation demonstrated in vivo EKLF occupancy at these sites and promoter reporter assays showed that EKLF activates gene transcription through these DNA elements. Furthermore, investigation of EKLF target genes in the yolk sac led to the discovery of unexpected additional defects in the embryonic red cell membrane and cytoskeleton. In short, EKLF regulates global erythroid gene expression that is critical for the development of primitive and definitive red cells.
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Pilon, Andre M., Douglas G. Nilson, Dewang Zhou, Jose Sangerman, Tim M. Townes, David M. Bodine, and Patrick G. Gallagher. "Alterations in Expression and Chromatin Configuration of the Alpha Hemoglobin-Stabilizing Protein Gene in Erythroid Krüppel-Like Factor-Deficient Mice." Molecular and Cellular Biology 26, no. 11 (June 1, 2006): 4368–77. http://dx.doi.org/10.1128/mcb.02216-05.

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ABSTRACT Erythroid Krüppel-like factor (EKLF) is an erythroid zinc finger protein identified by its interaction with a CACCC sequence in the β-globin promoter, where it establishes local chromatin structure permitting β-globin gene transcription. We sought to identify other EKLF target genes and determine the chromatin status of these genes in the presence and absence of EKLF. We identified alpha hemoglobin-stabilizing protein (AHSP) by subtractive hybridization and demonstrated a 95 to 99.9% reduction in AHSP mRNA and the absence of AHSP in EKLF-deficient cells. Chromatin at the AHSP promoter from EKLF-deficient cells lacked a DNase I hypersensitive site and exhibited histone hypoacetylation across the locus compared to hyperacetylation of wild-type chromatin. Wild-type chromatin demonstrated a peak of EKLF binding over a promoter region CACCC box that differs from the EKLF consensus by a nucleotide. In mobility shift assays, the AHSP promoter CACCC site bound EKLF in a manner comparable to the β-globin promoter CACCC site, indicating a broader recognition sequence for the EKLF consensus binding site. The AHSP promoter was transactivated by EKLF in K562 cells, which lack EKLF. These results support the hypothesis that EKLF acts as a transcription factor and a chromatin modulator for the AHSP and β-globin genes and indicate that EKLF may play similar roles for other erythroid genes.
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Basu, Priyadarshi, Tina K. Lung, Wafaa Lemsaddek, Thanh Giang Sargent, David C. Williams, Mohua Basu, Latasha C. Redmond, Jerry B. Lingrel, Jack L. Haar, and Joyce A. Lloyd. "EKLF and KLF2 have compensatory roles in embryonic β-globin gene expression and primitive erythropoiesis." Blood 110, no. 9 (November 1, 2007): 3417–25. http://dx.doi.org/10.1182/blood-2006-11-057307.

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Abstract The Krüppel-like C2/H2 zinc finger transcription factors (KLFs) control development and differentiation. Erythroid Krüppel-like factor (EKLF or KLF1) regulates adult β-globin gene expression and is necessary for normal definitive erythropoiesis. KLF2 is required for normal embryonic Ey- and βh1-, but not adult βglobin, gene expression in mice. Both EKLF and KLF2 play roles in primitive erythroid cell development. To investigate potential interactions between these genes, EKLF/KLF2 double-mutant embryos were analyzed. EKLF−/−KLF2−/− mice appear anemic at embryonic day 10.5 (E10.5) and die before E11.5, whereas single-knockout EKLF−/− or KLF2−/− embryos are grossly normal at E10.5 and die later than EKLF−/−KLF2−/− embryos. At E10.5, Ey- and βh1-globin mRNA is greatly reduced in EKLF−/−KLF2−/−, compared with EKLF−/− or KLF2−/− embryos, consistent with the observed anemia. Light and electron microscopic analyses of E9.5 EKLF−/−KLF2−/− yolk sacs, and cytospins, indicate that erythroid and endothelial cells are morphologically more abnormal than in either single knockout. EKLF−/−KLF2−/− erythroid cells are markedly irregularly shaped, suggesting membrane abnormalities. EKLF and KLF2 may have coordinate roles in a common progenitor to erythroid and endothelial cells. The data indicate that EKLF and KLF2 have redundant functions in embryonic β-like globin gene expression, primitive erythropoiesis, and endothelial development.
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Pilon, Andre M., Murat O. Arcasoy, Holly K. Dressman, Serena E. Vayda, Yelena D. Maksimova, Jose I. Sangerman, Patrick G. Gallagher, and David M. Bodine. "Failure of Terminal Erythroid Differentiation in EKLF-Deficient Mice Is Associated with Cell Cycle Perturbation and Reduced Expression of E2F2." Molecular and Cellular Biology 28, no. 24 (October 13, 2008): 7394–401. http://dx.doi.org/10.1128/mcb.01087-08.

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ABSTRACT Erythroid Krüppel-like factor (EKLF) is a Krüppel-like transcription factor identified as a transcriptional activator and chromatin modifier in erythroid cells. EKLF-deficient (Eklf −/− ) mice die at day 14.5 of gestation from severe anemia. In this study, we demonstrate that early progenitor cells fail to undergo terminal erythroid differentiation in Eklf −/− embryos. To discover potential EKLF target genes responsible for the failure of erythropoiesis, transcriptional profiling was performed with RNA from wild-type and Eklf −/− early erythroid progenitor cells. These analyses identified significant perturbation of a network of genes involved in cell cycle regulation, with the critical regulator of the cell cycle, E2f2, at a hub. E2f2 mRNA and protein levels were markedly decreased in Eklf −/− early erythroid progenitor cells, which showed a delay in the G1-to-S-phase transition. Chromatin immunoprecipitation analysis demonstrated EKLF occupancy at the proximal E2f2 promoter in vivo. Consistent with the role of EKLF as a chromatin modifier, EKLF binding sites in the E2f2 promoter were located in a region of EKLF-dependent DNase I sensitivity in early erythroid progenitor cells. We propose a model in which EKLF-dependent activation and modification of the E2f2 locus is required for cell cycle progression preceding terminal erythroid differentiation.
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Pilon, Andre M., Subramanian S. Ajay, Swathi Ashok Kumar, Laurie A. Steiner, Praveen F. Cherukuri, Stephen Wincovitch, Stacie M. Anderson, et al. "Genome-wide ChIP-Seq reveals a dramatic shift in the binding of the transcription factor erythroid Kruppel-like factor during erythrocyte differentiation." Blood 118, no. 17 (October 27, 2011): e139-e148. http://dx.doi.org/10.1182/blood-2011-05-355107.

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Abstract Erythropoiesis is dependent on the activity of transcription factors, including the erythroid-specific erythroid Kruppel-like factor (EKLF). ChIP followed by massively parallel sequencing (ChIP-Seq) is a powerful, unbiased method to map trans-factor occupancy. We used ChIP-Seq to study the interactome of EKLF in mouse erythroid progenitor cells and more differentiated erythroblasts. We correlated these results with the nuclear distribution of EKLF, RNA-Seq analysis of the transcriptome, and the occupancy of other erythroid transcription factors. In progenitor cells, EKLF is found predominantly at the periphery of the nucleus, where EKLF primarily occupies the promoter regions of genes and acts as a transcriptional activator. In erythroblasts, EKLF is distributed throughout the nucleus, and erythroblast-specific EKLF occupancy is predominantly in intragenic regions. In progenitor cells, EKLF modulates general cell growth and cell cycle regulatory pathways, whereas in erythroblasts EKLF is associated with repression of these pathways. The EKLF interactome shows very little overlap with the interactomes of GATA1, GATA2, or TAL1, leading to a model in which EKLF directs programs that are independent of those regulated by the GATA factors or TAL1.
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Perkins, Andrew C., Elise Coghill, Tina Maguire, Belinda Hartmann, Alasdair McDowall, Mitchell Weiss, Sean Grimmond, Janelle Keys, and Denise Hodge. "A Global Role for EKLF in Definitive and Primitive Erythropoiesis." Blood 106, no. 11 (November 16, 2005): 1745. http://dx.doi.org/10.1182/blood.v106.11.1745.1745.

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Abstract Erythroid Kruppel-like factor (EKLF or Klf1) is an erythroid specific C2H2 zinc-finger transcription factor which is essential for definitive erythropoiesis and β-globin gene expression. The absence of EKLF results in fatal anaemia but correction of globin chain imbalance does result in rescue, suggesting the existence of additional EKLF target genes. The aim of this study was to search for such genes by expression profiling. We performed profiling on fetal livers from wild-type versus EKLF null litter mates, and also EKLF null erythroid cell lines containing an inducible EKLF-ERTM fusion construct. Hybridisations were performed on microarray slides printed with a 23K oligo library from Compugen. Target gene validation was performed by real-time RT-PCR, chromatin immuno-precipitation (ChIP) and promoter-reporter assays. A large number of genes were down regulated in the absence of EKLF but few were up regulated, suggesting EKLF acts primarily as a transcriptional activator in vivo. One hundred genes were EKLF dependent in both systems. These include heme synthesis enzymes, red cell surface proteins including Rh and the transferrin receptor, and erythroid transcription factors. Two interesting highly EKLF-dependent genes are α-haemoglobin stabilising protein (AHSP), a key chaperone for free a-globin chains, and dematin (band 4.9) which links the cytoskeleton to the red cell membrane. A search for EKLF binding sites within the dematin and AHSP genes demonstrated a number of phylogenetically conserved CACC sites, and ChIP demonstrated in vivo EKLF occupancy at some but not all of these. Promoter-reporter assays showed EKLF directly activates dematin gene transcription through two promoters containing these sites. Lastly, investigation of EKLF target genes in the yolk sac lead to the discovery of unexpected defects in the embryonic red cell membrane and cytoskeleton. In conclusion, EKLF regulates global erythroid gene expression which is critical for development of primitive as well as definitive red cells.
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Coghill, Elise, Sarah Eccleston, Vanessa Fox, Loretta Cerruti, Clark Brown, John Cunningham, Stephen Jane, and Andrew Perkins. "Erythroid Kruppel-like factor (EKLF) coordinates erythroid cell proliferation and hemoglobinization in cell lines derived from EKLF null mice." Blood 97, no. 6 (March 15, 2001): 1861–68. http://dx.doi.org/10.1182/blood.v97.6.1861.

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Erythroid Kruppel-like factor (EKLF) is a transcription factor of the C2H2 zinc-finger class that is essential for definitive erythropoiesis. We generated immortal erythroid cell lines from EKLF−/− fetal liver progenitor cells that harbor a single copy of the entire human β-globin locus and then reintroduced EKLF as a tamoxifen-inducible, EKLF–mutant estrogen receptor (EKLF-ER™) fusion protein. Addition of tamoxifen resulted in enhanced differentiation and hemoglobinization, coupled with reduced proliferation. Human β-globin gene expression increased significantly, whereas γ-globin transcripts remained elevated at levels close to endogenous mouse α-globin transcript levels. We conclude that EKLF plays a role in regulation of the cell cycle and hemoglobinization in addition to its role in β-globin gene expression. The cell lines we used will facilitate structural and functional analyses of EKLF in these processes and provide useful tools for the elucidation of nonglobin EKLF target genes.
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Pilon, Andre M., Elliott H. Margulies, Hatice Ozel Abaan, Amy Werner Allen, Tim M. Townes, Abbie M. Frederick, Dewang Zhou, Patrick G. Gallagher, and David M. Bodine. "Genome-Wide Analysis of EKLF Occupancy in Erythroid Chromatin Reveals 5′, 3′ and Intragenic Binding Sites in EKLF Target Genes." Blood 112, no. 11 (November 16, 2008): 283. http://dx.doi.org/10.1182/blood.v112.11.283.283.

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Abstract Erythroid Kruppel-Like Factor (EKLF; KLF1) is the founding member of the Kruppel family of transcription factors, with 3 C2H2 zinc-fingers that bind a 9-base consensus sequence (NCNCNCCCN). The functions of EKLF, first identified as an activator of the beta-globin locus, include gene activation and chromatin remodeling. Our knowledge of genes regulated by EKLF is limited, as EKLF-deficient mice die by embryonic day 15 (E15), due to a severe anemia. Analysis of E13.5 wild type and EKLF-deficient fetal liver (FL) erythroid cells revealed that EKLF-deficient cells fail to complete terminal erythroid maturation (Pilon et al. submitted). Coupling chromatin immunoprecipitation and ultra high-throughput massively parallel sequencing (ChIP-seq) is increasingly being used for mapping protein-DNA interactions in vivo on a genome-wide scale. ChIP-seq allows a simultaneous analysis of transcription factor binding in every region of the genome, defining an “interactome”. To elucidate direct EKLF-dependent effects on erythropoiesis, we have combined ChIP-seq with expression array (“transcriptome”) analyses. We feel that integration of ChIP-seq and microarray data can provide us detailed knowledge of the role of EKLF in erythropoiesis. Chromatin was isolated from E13.5 FL cells of mice whose endogenous EKLF gene was replaced with a fully functional HA-tagged EKLF gene. ChIP was performed using a highly specific high affinity anti-HA antibody. A library of EKLF-bound FL chromatin enriched by anti-HA IP was created and subjected to fluorescent in situ sequencing on a Solexa 1G platform, providing 36-base signatures that were mapped to unique sites in the mouse genome, defining the EKLF “interactome.” The frequency with which a given signature appears provides a measurable peak of enrichment. We performed three biological/technical replicates and analyzed each data set individually as well as the combined data. To validate ChIP-seq results, we examined the locus of a known EKLF target gene, a-hemoglobin stabilizing protein (AHSP). Peaks corresponded to previously identified DNase hypersensitive sites, regions of histone hyperacetylation, and sites of promoter-occupancy determined by ChIP-PCR. A genome wide analysis, focusing on the regions with the highest EKLF occupancy revealed a set of 531 locations where high levels EKLF binding occurs. Of these sites, 119 (22%) are located 10 kb or more from the nearest gene and are classified as intergenic EKLF binding sites. Another 78 sites (14.6%) are within 10 kb of an annotated RefSeq gene. A plurality of the binding sites, 222 (42%), are within RefSeq coordinates and are classified as intragenic EKLF binding sites. Microarray profiling of mRNA from sorted, matched populations of dE13.5 WT and EKLF-deficient FL erythroid progenitor cells showed dysregulation of >3000 genes (p<0.05). Ingenuity Pathways Analysis (IPA) of the >3000 dysregulated mRNAs indicated significant alteration of a cell cycle-control network, centered about the transcription factor, E2f2. We confirmed significantly decreased E2f2 mRNA and protein levels by real-time PCR and Western blot, respectively; demonstrated that EKLF-deficient FL cells accumulate in G0/G1 by cell cycle analysis; and verified EKLF-binding to motifs within the E2f2 promoter by ChIP-PCR and analysis of the ChIP Seq data. We hypothesized that only a subset of the 3000 dysregulated genes would be direct EKLF targets. We limited the ChIP-seq library to display the top 5% most frequently represented fragments across the genome, and applied this criterion to the network of dysregulated mRNAs in the IPA cell cycle network. ChIP-seq identified peaks of EKLF association with 60% of the loci in this pathway. However, consistent with the role of EKLF as a transcriptional activator, 95% of the occupied genomic loci corresponded to mRNAs whose expression in EKLF-deficient FL cells was significantly decreased (p<0.05). The majority (59%) of these EKLF-bound sites were located at intragenic sites (i.e., introns), while a minority (15% and 26%) were found adjacent to the genes or in intergenic regions. We have shown that both the AHSP and E2f2 loci require EKLF to cause the locus to become activated and sensitive to DNase I digestion in erythroid cells. Based on the increased frequency of intragenic EKLF-binding sites, particularly in genes of the cell cycle network, we propose that the occupancy of intragenic sites by EKLF may facilitate chromatin modification.
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Perkins, Andrew C., Janelle R. Keys, Denise J. Hodge, and Michael R. Tallack. "Erythroid Kruppel-Like Factor Regulates E2F4 and the G1 Cdk Inhibitor, p18." Blood 106, no. 11 (November 16, 2005): 1357. http://dx.doi.org/10.1182/blood.v106.11.1357.1357.

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Abstract Erythroid Kruppel-Like Factor (EKLF) is a zinc finger transcription factor which is essential for β-globin gene expression. Knockout mice die from anemia at E15, but restoration of globin chain imbalance does not rescue anemia or increase survival. Cell lines derived from EKLF null mice undergo proliferation arrest upon reactivation of a conditional EKLF-ER fusion protein, suggesting a role in cell cycle control. A transcriptional profiling experiment comparing the global gene expression in EKLF null and wild type fetal liver identified many differentially expressed genes, a number of which function in G1 and at the G1/S checkpoint of the cell cycle. The Cyclin dependent kinase (Cdk) inhibitor, p18, and the S phase transcription factor E2F4 were both found to be significantly down regulated in EKLF null mice and this result was confirmed by real-time PCR. Interestingly, E2F4 knockout mice have a similar phenotype to EKLF knockout mice. Bioinformatic searches of the p18 and E2F4 genes shows that each contains phylogenetically conserved CACC box motifs capable of binding EKLF within longer regions of conservation in promoter and intron regions. The p18 gene contains two conserved CACCC sites upstream of the start of transcription, which are required for EKLF dependent promoter activity in luciferase reporter assays. The transcription factor E2F4 contains a conserved EKLF-binding CACC site within an intron that is closely associated with two conserved GATA1 binding sites. We show by a chromatin immunoprecipitation (ChIP) assays that the E2F4 intron and p18 promoter are occupied by EKLF in vivo. Together, these results suggest that EKLF is likely to directly regulate expression of key cell cycle genes in vivo to drive the switch from proliferation to differentiation of erythrocytes. The loss of EKLF is likely to result in aberrant proliferation and predisposition to leukemia.
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Drissen, Roy, Marieke von Lindern, Andrea Kolbus, Siska Driegen, Peter Steinlein, Hartmut Beug, Frank Grosveld, and Sjaak Philipsen. "The Erythroid Phenotype of EKLF-Null Mice: Defects in Hemoglobin Metabolism and Membrane Stability." Molecular and Cellular Biology 25, no. 12 (June 15, 2005): 5205–14. http://dx.doi.org/10.1128/mcb.25.12.5205-5214.2005.

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ABSTRACT Development of red blood cells requires the correct regulation of cellular processes including changes in cell morphology, globin expression and heme synthesis. Transcription factors such as erythroid Krüppel-like factor EKLF (Klf1) play a critical role in erythropoiesis. Mice lacking EKLF die around embryonic day 14 because of defective definitive erythropoiesis, partly caused by a deficit in β-globin expression. To identify additional target genes, we analyzed the phenotype and gene expression profiles of wild-type and EKLF null primary erythroid progenitors that were differentiated synchronously in vitro. We show that EKLF is dispensable for expansion of erythroid progenitors, but required for the last steps of erythroid differentiation. We identify EKLF-dependent genes involved in hemoglobin metabolism and membrane stability. Strikingly, expression of these genes is also EKLF-dependent in primitive, yolk sac-derived, blood cells. Consistent with lack of upregulation of these genes we find previously undetected morphological abnormalities in EKLF-null primitive cells. Our data provide an explanation for the hitherto unexplained severity of the EKLF null phenotype in erythropoiesis.
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Dissertations / Theses on the topic "Eklf"

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Desgardin, Aurelie D. "EKLF-meidated transcription of erythroid genes." Thesis, Kingston University, 2010. http://eprints.kingston.ac.uk/20434/.

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Erythroid Kruppel-like factor (EKLF) is an erythroid specific transcription factor that binds to the proximal [beta]-globin gene promoter and is essential for high level expression. In addition, EKLF binds to the far upstream enhancer commonly referred to as the Locus Control Region (LCR). The nature of these two events, their relationship to other events at the multigene [beta]-globin locus and the precise and required interaction of these cis-acting sequences remains unclear. Equally, the mode of action ofEKLF at other erythroid-specific gene loci that are not regulated by an LCR has not yet been reported. These targets include chaperones, membrane-bound proteins, and enzymes of the heme biosynthesis pathway that are essential for red blood cell function. To elucidate the role of EKLF at the multigene locus, and at other erythroid genes, we monitored the temporal EKLF-directed events across the [beta]-globin locus, at the AHSP and Dematin as well as the ALAD promoter using a unique 4-0H-Tamoxifen EKLF-inducible erythroid cell line (JH31), developed in the laboratory, chromatin immunoprecipitation (ChIP) studies, and DNasel hypersensitivity assays. We demonstrate here that EKLF is not required for priming of the [beta]-globin locus for expression. However, EKLF is essential for maximal erythroid factor occupancy, recruitment of chromatin-modifying enzymes, and effective recruitment of the RNA Polymerase II complex. We show that EKLF recruits these complexes first to the LCR prior to the [beta]-globin promoter, suggesting that the LCR serves as a docking element. Finally we provide evidence that the LCR/promoter interacting factor, Ldb-l, is recruited to the [beta]-promoter in an EKLF-dependent manner. We extend our observations to several EKLF-regulated genes outside the [beta]-globin cluster, demonstrating not only the kinetics of transcriptional activation, but also a previously unknown mechanism of chromatin remodeling that implicates histone eviction. Finally, we report a discrepancy between the roles of the histone acetyltransferases CBP and p300 at EKLF target gene promoters, challenging conservative notions of basic transcriptional events. Together, our observations deepen our understanding of the mechanisms of action of EKLF, and provide a platform for additional studies.
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Lung, Tina Kathy. "Analysis of Mouse EKLF/KLF2 E9.5 Double Knockout: Yolk Sac Morphology and Embryonic Erythroid Maturation." VCU Scholars Compass, 2007. http://hdl.handle.net/10156/1821.

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Bouilloux, Fabrice. "Rôle du facteur de transcription EKLF dans le contrôle de la fourche de différenciation érrythro-mégacaryocytaire." Lyon 1, 2008. http://n2t.net/ark:/47881/m6833q4v.

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EKLF et FLI-1 sont deux facteurs de transcription antagonistes activant respectivement la transcription des gènes spécifiques des lignées érythrocytaire et mégacaryocytaire qui dérivent d'un progéniteur bipotent commun. L'absence de EKLF favorise l'immortalisation des cellules érythrocytaires et la production dérégulée de FLI-1 est une cause récurrente de leur transformation. Afin de préciser le rôle de EKLF, son expression a été modulée dans des cellules érythroleucémiques ou dans des progéniteurs multipotents hématopoïétiques humains. Nos résultats montrent que EKLF n'a d'effet antiprolifératif ni dans des cellules érythroleucémiques surexprimant FLI-1 ni dans des progéniteurs natifs, mais favorise l'engagement du progéniteur bipotent vers la différenciation érythrocytaire au détriment de celle mégacaryocytaire. Ce rôle de EKLF ne dépend pas de sa capacité à lier l'ADN, mais s'explique au moins en partie par l'inhibition du recrutement de FLI-1 sur les promoteurs mégacaryocytaires
EKLF and FLI-1 are antagonistic transcription factors driving the specific gene expression of erythrocytic and megakaryocytic lineage respectively, which derive from a common bipotent progenitor. FLI-1 overexpression is observed recurrently in Friend erythroleukemia and immortalisation of the erythrocytic lignage is favoured by EKLF knock out. In order to study the EKLF functions, its expression level has been modulated in erythroleucemic cells and in human mulitpotent hematopoietic progenitors. Our results failed to evidence any antiproliferation effect of EKLF neither in Friend erythroleukemic cells nor in multipotent prognitors. On the other hand, EKLF favours the erythrocytic at the expense of megakaryocytic differentiation of the bipotent progenitor. This effect is not dependent on the EKLF DNA binding ability and can be explained, at least in part, by the inhibition of FLI-1 recruitment on megakaryocytic promoters
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Richardson, Ben Matthew. "A proteomic approach to characterising erythropoiesis in both normal and In(Lu) phenotypes, with investigations into EKLF function." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492444.

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Erythropoiesis is the process in which a pluripotent stem cell differentiates into a mature red blood cell (RBC). Over the last two decades understanding of factors that regulate this process has increased, which has allowed for the development of advanced in vitro culture systems that can on a small scale, generate therapeutic quantities of mature RBCs from isolated stem cell populations. Not only does this create an alternative source of RBCs for use in medical treatments, it also provides a esearch model that can be used to investigate the underlying biochemical and physiological mechanisms of human erythropoiesis.
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Ma, Rui. "Optimizing the production of erythroid cells from human embryonic stem cells." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/17979.

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Red blood cell (RBC) transfusion is the major treatment for patients suffering from trauma or severe anaemias, and life-long transfusion may be needed to alleviate symptoms and maintain body functioning. However, with a relatively low portion of people are donating, shortage in blood supply is becoming a life-threatening issue in the aging society. Among attempts to identify novel sources for transfusion medicine, human pluripotent stem cells (hPSCs), including embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) are currently the most promising candidate, which is capable of producing donor-independent, pathogen-free and immunologically compatible RBCs. Currently, hESC-derived erythropoiesis in vitro is considered to mimic the very primitive yolk sac haematopoiesis, indicated by a low or absent level of β globin production and incomplete enucleation. Thus these cells are not mature enough to be used in transfusion medicine. The aim of this PhD project was to overexpress a key erythroid transcription factor, Erythroid Krüppel-like factor (EKLF or KLF1) in an inducible manner to improve the maturation of hESC-derived erythroid cells. EKLF is a member of the Krüppel-like factor family, which is characterized by three C2H2 type zinc finger motifs. EKLF expression in vivo is highly restricted to erythroid cells in yolk sac, fetal liver, spleen and the bone marrow, although recently a low-level of expression was found in haematopoietic precursors. Published reports demonstrate that EKLF can 1) activate β globin expression by binding to the CACCC box in its promoter or by altering β-like globin locus chromatin structure; 2) exert a role in MEP (common progenitor for erythrocytes and megakaryocytes) stage by favouring erythroid differentiation against megakaryocyte differentiation; 3) promote enucleation by affecting the DNase II-alpha expression in the central macrophage of a fetal liver erythroblastic island; 4) act as an instructive factor for lineage commitment towards erythroid fate in HSCs. In this project, 1) We tested and evaluated a feeder-free, serum-free differentiation system for deriving erythroid cells from hESCs; 2) We constructed constitutive and inducible EKLF expression vectors and validated them in K562 cells; 3) We generated hESC lines carrying these EKLF expression vectors and assessed their effects on erythrocyte production and maturation. We found that our differentiation system was capable of generating haematopoietic progenitors (HPCs) and erythroid cells at high efficiency. Using this differentiation system, we concluded that enhanced expression of EKLF upregulated adult β globin expression selectively, without altering expressions of other globins. This finding provides hints for the development of novel approaches to “reprogramme” hESCs towards a certain fate and overexpression of EKLF in this differentiation system may be beneficial for resolving issues in future transfusion medicine.
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Lau, Winnie. "Studies of human EKLF mutations associated with the In(Lu) blood group phenotype and a rare variant of congenital dyserlthropoietic anaemia." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529878.

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Jansen, Valerie Malyvanh. "Generation and characterization of a knock-in allele of EKLF probing the in vivo role of the chromatin remodeling domain in definitive hematopoietic cells /." View the abstract View the abstract Download the full-text PDF version Download the full-text PDF version, 2009. http://etd.uthsc.edu/ABSTRACTS/2009-025-Jansen-index.htm.

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Thesis (Ph.D.)--University of Tennessee Health Science Center, 2009.
Title from title page screen (viewed on February 4, 2010). Research advisor: John M. Cunningham, M.D. Document formatted into pages (xiv, 115 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 89-103).
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Hallal, Samantha. "Characterisation of the zinc fingers of Erythroid Kruppel-Like Factor." University of Sydney, 2008. http://hdl.handle.net/2123/4030.

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Doctor of Philosophy (PhD)
Gene expression is known to be regulated at the level of transcription. Recently, however, there has been a growing realisation of the importance of gene regulation at the post-transcriptional level, namely at the level of pre-mRNA processing (5’ capping, splicing and polyadenylation), nuclear export, mRNA localisation and translation. Erythroid krüppel-like factor (Eklf) is the founding member of the Krüppel-like factor (Klf) family of transcription factors and plays an important role in erythropoiesis. In addition to its nuclear presence, Eklf was recently found to localise to the cytoplasm and this observation prompted us to examine whether this protein has a role as an RNA-binding protein, in addition to its well-characterised DNA-binding function. In this thesis we demonstrate that Eklf displays RNA-binding activity in an in vitro and in vivo context through the use of its classical zinc finger (ZF) domains. Furthermore, using two independent in vitro assays, we show that Eklf has a preference for A and U RNA homoribopolymers. These results represent the first description of RNA-binding by a member of the Klf family. We developed a dominant negative mutant of Eklf by expressing its ZF region in murine erythroleukaemia (MEL) cells. We used this to investigate the importance of this protein in haematopoietic lineage decisions by examining its effect on the multipotent K562 cell line. We provide evidence that Eklf appears to be critical not only for the promotion of erythropoiesis, but also for the inhibition of megakaryopoiesis.
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Canadas, Maria Belen. "Cooperative EKF localization." [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11730075.

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Matheson, Iggy. "Angles-Only EKF Navigation for Hyperbolic Flybys." DigitalCommons@USU, 2019. https://digitalcommons.usu.edu/etd/7608.

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Space travelers in science fiction can drop out of hyperspace and make a pinpoint landing on any strange new world without stopping to get their bearings, but real-life space navigation is an art characterized by limited information and complex mathematics that yield no easy answers. This study investigates, for the first time ever, what position and velocity estimation errors can be expected by a starship arriving at a distant star - specifically, a miniature probe like those proposed by the Breakthrough Starshot initiative arriving at Proxima Centauri. Such a probe consists of nothing but a small optical camera and a small microprocessor, and must therefore rely on relatively simple methods to determine its position and velocity, such as observing the angles between its destination and certain guide stars and processing them in an algorithm known as an extended Kalman filter. However, this algorithm is designed for scenarios in which the position and velocity are already known to high accuracy. This study shows that the extended Kalman filter can reliably estimate the position and velocity of the Starshot probe at speeds characteristic of current space probes, but does not attempt to model the filter’s performance at speeds characteristic of Starshot-style proposals. The gravity of the target star is also estimated using the same methods.
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Books on the topic "Eklf"

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Eklo yātrī: Kavitāsaṅgraha. [Kathmandu]: Mīnā Śarmā, 2000.

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Ṭhākurāmā eklo mānche: Jīvanī. Lalitapura: Jagadambā Prakāśana, 2010.

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1952-2002: CECA = EKSF = ECSC. Luxembourg: Office des publications officielles des Communautés européenes, 2002.

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Vāsuśaśī. Saṃsāramā sababhandā eklo jīva: Upanyāsa. Kāṭhamāḍauṃ: Ratna Pustaka Bhaṇḍāra, 1995.

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Kahraman, Tahir. Çağdaş Türkiye Türkçesindeki fiilerin durum ekli tamlayıcıları. Ankara: Atatürk Kültür, Dil ve Tarih Yüksek Kurumu, Türk Dil Kurumu, 1996.

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Takáts, József. Az újragondolt város: EKF-iratok. Pécs: Publikon, 2011.

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Commission, European. CECA - EKSF - EGKS - EKAX - ECSC - EHTY - EKSG: 1952-2002. Luxembourg: Office for Official pubs. of the E.C., 2002.

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CECA EKSF EGKS EKAX ECSC EHTY EKSG: 1952-2002 : 27.6.2002: Actas - Schlussakte - actes - atti. Luxembourg: Office des publications officielles des Communautés européenes, 2002.

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Schindelka, Martina. Die Europäische Kampagne für den ländlichen Raum 1987/88 (EKL): Eine kulturwissenschaftliche Studie unter besonderer Berücksichtigung kommunikativer Aspekte. Berlin: Pro Business, 2002.

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Liit, Eesti Kunstnike. Vastandumised: EKL 10. aastanäitus : 19.06.-25.07.2010, Tallinna Kunstihoone = Confrontations : 10th Annual Exhibition of Estonian Artists' Association : 19.06.-25.07.2010, Tallinn Art Hall. [Tallinn]: Eesti Kunstnike Liit, 2010.

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Book chapters on the topic "Eklf"

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Bieker, James J. "Expanded Role for EKLF/KLF1 Within the Hematopoietic Lineage." In The Biology of Krüppel-like Factors, 83–93. Tokyo: Springer Japan, 2009. http://dx.doi.org/10.1007/978-4-431-87775-2_6.

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Lagunas, M. A., A. Perez-Neira, and D. Maiwald. "EKF Schemes in Array Processing." In Acoustic Signal Processing for Ocean Exploration, 619–24. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1604-6_59.

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Schottky, B., and D. Saad. "Exact Learning Curves for EKF Training." In ICANN 98, 535–40. London: Springer London, 1998. http://dx.doi.org/10.1007/978-1-4471-1599-1_80.

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Elibol, Armağan, Nuno Gracias, and Rafael Garcia. "Combined ASKF-EKF Framework for Topology Estimation." In Efficient Topology Estimation for Large Scale Optical Mapping, 41–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-30313-5_4.

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Schmidt, Adam. "Multi-robot, EKF-Based Visual SLAM System." In Computer Vision and Graphics, 562–69. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-11331-9_67.

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Cao, Jing, Jidong Feng, Wanjie Ren, Wanfeng Ma, Mingran Li, and Yuan Xu. "Human Tracking Using Distributed Dual-EKF Filter." In IoT and Big Data Technologies for Health Care, 394–401. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-94182-6_31.

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Jain, Ankur, and B. K. Roy. "Simultaneous Vehicle Steering and Localization Using EKF." In Conference Proceedings of ICDLAIR2019, 210–19. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-67187-7_23.

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Huang, Guoquan, Kevin Eckenhoff, and John Leonard. "Optimal-State-Constraint EKF for Visual-Inertial Navigation." In Springer Proceedings in Advanced Robotics, 125–39. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-51532-8_8.

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Lee, S. C., W. R. Lee, and K. H. You. "TDoA Based UAV Localization Using Dual-EKF Algorithm." In Communications in Computer and Information Science, 47–54. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-10741-2_6.

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Huang, Guoquan P., Anastasios I. Mourikis, and Stergios I. Roumeliotis. "A First-Estimates Jacobian EKF for Improving SLAM Consistency." In Experimental Robotics, 373–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-00196-3_43.

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Conference papers on the topic "Eklf"

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Jin, Zeming, Ling Wang, Hanhan Liu, Ronghua Du, and Xiang Zhang. "Monocular-Based Pose Estimation of Non-Cooperative Space Targets Using EKF and EKPF." In 2020 13th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics (CISP-BMEI). IEEE, 2020. http://dx.doi.org/10.1109/cisp-bmei51763.2020.9263615.

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Li, Chang, and Roger Fales. "Application of Extended Kalman Filter in a Forced-Feedback Metering Poppet Valve System." In ASME 2008 Dynamic Systems and Control Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/dscc2008-2247.

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This work focuses on an accurate Extended Kalman Filter (EKF) estimator, which is applied in a forced-feedback metering poppet valve system (FFMPVS). The EKF estimator is used to estimate the position and velocity of the main poppet valve, the pilot poppet valve and the piston through using the control volume pressure, the load pressure and the pressure between the pilot poppet and the actuator housing, which are all disturbed by noise. The EKF estimator takes advantage of its recursive optimal state estimation to estimate the states of this metering poppet valve, which is a non-linear, time-variant dynamical system in real time. The EKF estimator has robustness to parameter variations and ability to filter measurement noises. It is shown that the EKF estimator tracks the states confidently and promptly for both the steady-state and transient performance, at the same time, the EKF estimator also filters the noise of the measured pressures.
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Bryan, Josiah A., and Roger C. Fales. "Estimating Cutting Force Coefficients in High-Speed Low-Radial-Immersion Milling Processes." In ASME 2014 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/dscc2014-5930.

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A high-speed milling system is considered, which is prone to chatter vibration, a stability condition dependent on system parameters (e.g., cutting force coefficients). This work is motivated by the need for model parameters which can be used in stability analysis. An Extended Kalman Filter (EKF) is proposed to estimate cutting force coefficients for each tooth in a low-radial-immersion milling process to aid chatter stability prediction. The proposed EKF utilizes tool deflection measurements and no force measurements. The model used in the EKF is found to be observable, a quality required to achieve valid state estimations. Running the EKF with experimental tool deflection measurements produces estimates of cutting force coefficients that result in good correlation between simulation (using the estimated coefficients) and experiment. Such an EKF may help customize chatter stability analysis to any particular tool-workpiece system.
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Zhu, Meiyin, Xi Wang, Shubo Yang, Huairong Chen, Keqiang Miao, and Nannan Gu. "Two Degree-of-Freedom µ Synthesis Control With Kalman Filter for Flight Environment Simulation Volume With Sensors Uncertainty." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-90116.

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Abstract Flight Environment Simulation Volume (FESV) is the most important subsystem of Altitude Ground Test Facilities (AGTF). Its control precision of temperature and pressure determines the level of test ability of AGTF. However, in practice, the sensor hysteresis and noise may greatly affect the control precision of FESV. To improve the control performance of FESV in practice, a new control structure of two degree-of-freedom (DOF) μ synthesis control with the extended Kalman filter (EKF) considering actuators and sensors uncertainty is proposed, which constitutes a core support part of the paper. For the problem of sensors de-noising, an EKF is devised to provide a credible feedback signal to the two DOF μ controller. Aiming at the problem of reference command’s rapid change, one freedom feed forward is adopted, while another freedom output feedback is used to ensure good servo tracking as well as disturbance and noise rejection; furthermore to overcome the overshoot problem and acquire dynamic tuning, an integral is introduced in inner loop; additionally, two performance weighting functions are designed to achieve robustness and control energy limit considering the uncertainties in system. In order to verify the effectiveness of the designed two DOF μ synthesis controller with EKF, we suppose a typical engine test condition with Zoom-Climb and Mach Dash and consider time delay and Gaussian noise in the sensors. The simulation results show that the designed two DOF μ synthesis controller with EKF has good servo tracking and noise rejection performance and the relative steady-state and transient errors of temperature and pressure are both less than 0.1% and 0.2% respectively. Additionally, we validate the robust performance of the designed two DOF μ controller with EKF by using the upper bound value of the uncertainty parameters. Furthermore, to verify the advantage of the designed two DOF μ controller with EKF, we compare its control results with those of without EKF and μ controller without considering sensor time delay. The comparison results show that the designed two DOF μ controller with EKF provides better performance. Finally, to verify the advantage of μ synthesis controller, we designed a PID controller and compare the simulation result with μ controller, the comparison result show that the designed μ controller is better than PID controller.
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Gurung, H., S. Karmakar, and A. Banerjee. "Development of an Extended Kalman Filter for Self-Sensing Application of Shape Memory Alloy Wire Actuator." In ASME 2015 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/smasis2015-9021.

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This paper presents the development of an Extended Kalman Filter (EKF) for self-sensing application of Shape Memory Alloy (SMA) wire actuator. The EKF is used to estimate the end displacement of a SMA wire actuated compliant link using the electrical resistance variation of SMA. The model of the system is developed by coupling the stress-deformation relation of the link along the direction of the SMA actuator with the phenomenological model of the SMA wire. In EKF, the stress and temperature of SMA comprise the state vector and its electrical resistance is considered as output. The developed EKF is validated, by comparing the estimated system response with that of the model for a given input signal. The effects of the process and measurement noise on the estimation error have also been studied. An experimental setup is developed to measure the change in electrical resistance of the SMA wire, voltage drop across the same, and the associated end-displacement of the compliant link. Using the measured data, the end-displacement of the link is estimated using EKF and compared with the experimentally measured end-displacement. Significant qualitative agreement is observed. It is noted, that the convective heat transfer coefficient significantly affects the quantitative discrepancy. Thus the coefficient of convective heat transfer is determined, so as to minimize the gap between the two responses for a particular applied voltage. The coefficient is then used for different set of experiments, revealing the true potential of the EKF based approach to harness the self-sensing capability of SMA.
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Wang, Zhitao, Junxin Zhang, Wanling Qi, and Shuying Li. "Parameter Estimation and Performance Seeking of a Marine Gas Turbine Based on Extended Kalman Filter." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-16090.

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Abstract Marine gas turbines have been widely used and developed in the field of marine power. It is important to make them operated safely and efficiently. In this paper, a marine triaxial gas turbine is taken as an example to study the method of estimating the health state of the gas path using extended Kalman filter (EKF). To verify the accuracy of EKF, a comparison was made between linearized Kalman filtering (LKF) and EKF. In addition, the sequential quadratic programming (SQP) algorithm is used to seek the performance in case of gas path abnormal. The combination of parameter estimation and performance seeking forms a comprehensive method for diagnosis and optimization of marine gas turbines. The results show that the EKF method is an effective method for combining nonlinear systems with traditional Kalman filter. EKF has a good estimation effect on the gas path health state under different operating conditions. Also, the marine triaxial gas turbine achieved the target performance under the constraints of the SQP algorithm. Performance seeking restores the output power of the marine gas turbine and reduces the inlet and outlet temperatures of turbines. It can effectively prevent the problem of excessive combustion and ensure the safe and stable operation of the marine gas turbine.
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Wang, Wen, Xinxin Li, and Zichen Chen. "A New Friction Estimation Approach for Precision Positioner." In 2007 First International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2007. http://dx.doi.org/10.1115/mnc2007-21535.

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Precision positioner has been significantly developed as the rapid growth of MEMS and IC industries. As for short-stroke position, the loss of friction can be avoided by using flexible hinges. Long-stroke postioner, however, in which moved-to-be mass always stands on the guide-way part, a main source of friction, makes friction unavoidable. Friction estimation is based on certain filters, such as Extended Kalman filter (EKF). However, estimation accuracy of Kalman filter, especially at low-velocity movement, is not very well. To solve this problem, the paper proposes an estimation method based on DD2 to make an accurate estimation. And the result shows this method is promising in real-time friction estimation. After background introduction, in section 2, the relation of EKF and Taylor series and EKF implementation are reviewed and its limitations are noted as well. A briefly introduction to DD2 is given in Section 3 and friction estimation case comparing the simulation results of DD2 estimation with that of EKF described in Section 4, respectively. At last, conclusions are summarized.
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Sarim, Mohammad, Alireza Nemati, Manish Kumar, and Kelly Cohen. "Extended Kalman Filter Based Quadrotor State Estimation Based on Asynchronous Multisensor Data." In ASME 2015 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/dscc2015-9929.

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For effective navigation and tracking applications involving Unmanned Aerial Vehicles (UAVs), data fusion from multiple sensors is utilized. However, asynchronous nature of the sensors, coupled with loss of data and communication delays, makes this process not very reliable. For a better estimation of the data, some sort of filtering scheme is needed. This paper presents an Extended Kalman Filter (EKF) based quadrotor state estimation by exploiting the dynamic model of the UAV. The data coming from the sensors is noisy and intermittent. The EKF filters and provides estimated data for the missing timestamps. An indoor flight test establishes the accuracy of the EKF, and another outdoor flight test validates the developed scheme for the real world scenario.
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Zhao, Shi, Adrien M. Bizeray, Stephen R. Duncan, and David A. Howey. "Performance Evaluation of an Extended Kalman Filter for State Estimation of a Pseudo-2D Thermal-Electrochemical Lithium-Ion Battery Model." In ASME 2015 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/dscc2015-9836.

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Fast and accurate state estimation is one of the major challenges for designing an advanced battery management system based on high-fidelity physics-based model. This paper evaluates the performance of a modified extended Kalman filter (EKF) for on-line state estimation of a pseudo-2D thermal-electrochemical model of a lithium-ion battery under a highly dynamic load with 16C peak current. The EKF estimation on the full model is shown to be significantly more accurate (< 1% error on SOC) than that on the single-particle model (10% error on SOC). The efficiency of the EKF can be improved by reducing the order of the discretised model while maintaining a high level of accuracy. It is also shown that low noise level in the voltage measurement is critical for accurate state estimation.
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Wilbanks, J. Justin, and Michael J. Leamy. "Uncertain Parameter Estimation Approaches for Increasing the Effectiveness of Command-Shaped Engine Restart Strategies." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-67548.

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This paper develops recursive least-squares (RLS) and extended Kalman filtering (EKF) approaches for estimating uncertain engine friction (and other) parameters necessary for successful implementation of a two-scale command shaping (TSCS) engine restart strategy. The TSCS strategy has been developed for mitigating vibrations in conventional and hybrid electric vehicle (HEV) powertrains during internal combustion engine (ICE) restart. Implementing the TSCS strategy increases the drivability of a HEV by reducing noise, vibration, and harshness (NVH) issues associated with ICE restart during a powertrain mode transition. This is accomplished primarily, by modifying the electric machine (EM) torque profile with linear and time-varying components over multiple time scales. For full implementation, the TSCS strategy requires input parameters characterizing the ICE which may be a) difficult to quantify, and/or b) uncertain due to their dependence on engine operating temperature and other environmental considerations. RLS and EKF algorithms tailored to TSCS are presented herein for estimating these parameters. It is shown that both the RLS and EKF algorithms can be used to estimate the necessary ICE parameters and increase effectiveness of the TSCS strategy. The EKF algorithm, in particular, estimates uncertain ICE parameters with minimal measurement requirements, giving it an advantage over the presented RLS algorithm.
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Reports on the topic "Eklf"

1

Bergström, Ulf, and Mårten Erlandsson. Spiggens påverkan på rekryteringsområden för abborre och gädda i Östersjön. Institutionen för akvatiska resurser, Sveriges lantbruksuniversitet, 2022. http://dx.doi.org/10.54612/a.4bb5blrfa9.

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Storspigg har visat sig ha en negativ påverkan på rekryteringen av rovfiskar längs Östersjökusten, framför allt gädda och abborre, genom predation på ägg och larver. Detta leder till minskade rovfiskbestånd i kustzonen och en förlust av viktiga ekosystemfunktioner. I den här studien har vi kvantifierat omfattningen av denna störning med hjälp av rumslig och statistisk modellering där vi undersöker hur utbredning och abundans av rovfiskens reproduktionsområden förändrats över tid. I analyserna nyttjar vi data från de omfattande undersökningar av kustfiskens reproduktion längs ostkusten som gjorts med hjälp av tryckvåg från slutet av 1970-talet och framåt. Vi har tillämpat tre olika analysmetoder för att skatta förändringen i reproduktionsområden, i syfte att få en uppfattning om spannet i uppskattningarna. Vi har nyttjat två modeller från redan publicerade vetenskapliga artiklar, och även utvecklat en ny modell. Den ena av de två publicerade modellerna beskriver utvecklingen i täthet abborre och spigg över tid (Eriksson m fl 2021), medan den andra beskriver utvecklingen av ytor med rovfiskdominans (Eklöf m fl 2020). Den nyutvecklade modellen beskriver i sin tur förändringar i ytan lämpliga reproduktionsområden för abborre och gädda. De olika analyserna har i någon mån varierande geografisk täckning, som mest omfattande kuststräckan från norra Skåne län till södra Gävleborgs län. Sammantaget visar analyserna på betydande nedgångar i reproduktionen av abborre och gädda längs centrala Östersjökusten de senaste 30-40 åren. Resultaten visar att ytan fungerande reproduktionsområden för abborre och gädda minskat med i storleksordningen 40-65%, medan tätheten abborryngel kan ha minskat med så mycket som 80 %. Det är framför allt tidigare mycket produktiva rekryteringsområden för abborre och gädda längs öppna kuststräckor och i mellan- och ytterskärgårdar som gått förlorade. De tydliga sambanden mellan spigg och rekrytering av abborre och gädda indikerar att spiggen har varit en starkt bidragande orsak till nedgången, och framför allt att spiggen sannolikt blockerar en återkomst av abborre och gädda till områden där reproduktionen slagits ut. Förlusten av lokala rovfiskbestånd i skärgårdarna har en negativ påverkan inte bara på fisket, utan minskar även kustekosystemets förmåga att motstå de negativa effekterna av övergödning. En angelägen fråga för kommande forskning är att förstå mekanismerna bakom den dramatiska spiggökningen, och att identifiera metoder för att stärka reproduktionen och återetablera bestånd av abborre och gädda i de störda områdena.
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