| 1. |
- Filipek-Gorniok, Beata, et al.
(författare)
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Expression of chondroitin/dermatan sulfate glycosyltransferases during early zebrafish development
- 2013
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Ingår i: Developmental Dynamics. - : Wiley. - 1058-8388 .- 1097-0177. ; 242:8, s. 964-975
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Tidskriftsartikel (refereegranskat)abstract
- Background: Chondroitin/dermatan sulfate (CS/DS) proteoglycans present in the extracellular matrix have important structural and regulatory functions. Results: Six human genes have previously been shown to catalyze CS/DS polymerization. Here we show that one of these genes, chpf, is represented by two copies in the zebrafish genome, chpfa and chpfb, while the other five human CS/DS glycosyltransferases csgalnact1, csgalnact2, chpf2, chsy1, and chsy3 all have single zebrafish orthologues. The putative zebrafish CS/DS glycosyltransferases are spatially and temporally expressed. Interestingly, overlapping expression of multiple glycosyltransferases coincides with high CS/DS deposition. Finally, whereas the relative levels of the related polysaccharide HS reach steady-state at around 2 days post fertilization, there is a continued relative increase of the CS amounts per larvae during the first 6 days of development, matching the increased cartilage formation. Conclusions: There are 7 CS/DS glycosyltransferases in zebrafish, which, based on homology, can be divided into the CSGALNACT, CHSY, and CHPF families. The overlap between intense CS/DS production and the expression of multiple CS/DS glycosyltransferases suggests that efficient CS/DS biosynthesis requires a combination of several glycosyltransferases.
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| 2. |
- Holmborn, Katarina, et al.
(författare)
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On the Roles and Regulation of Chondroitin Sulfate and Heparan Sulfate in Zebrafish Pharyngeal Cartilage Morphogenesis
- 2012
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 287:40, s. 33905-33916
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Tidskriftsartikel (refereegranskat)abstract
- The present study addresses the roles of heparan sulfate (HS) proteoglycans and chondroitin sulfate (CS) proteoglycans in the development of zebrafish pharyngeal cartilage structures. uxs1 and b3gat3 mutants, predicted to have impaired biosynthesis of both HS and CS because of defective formation of the common proteoglycan linkage tetrasaccharide were analyzed along with ext2 and extl3 mutants, predicted to have defective HS polymerization. Notably, the effects on HS and CS biosynthesis in the respective mutant strains were shown to differ from what had been hypothesized. In uxs1 and b3gat3 mutant larvae, biosynthesis of CS was shown to be virtually abolished, whereas these mutants still were capable of synthesizing 50% of the HS produced in control larvae. extl3 and ext2 mutants on the other hand were shown to synthesize reduced amounts of hypersulfated HS. Further, extl3 mutants produced higher levels of CS than control larvae, whereas morpholino-mediated suppression of csgalnact1/csgalnact2 resulted in increased HS biosynthesis. Thus, the balance of the Extl3 and Csgalnact1/Csgalnact2 proteins influences the HS/CS ratio. A characterization of the pharyngeal cartilage element morphologies in the single mutant strains, as well as in ext2;uxs1 double mutants, was conducted. A correlation between HS and CS production and phenotypes was found, such that impaired HS biosynthesis was shown to affect chondrocyte intercalation, whereas impaired CS biosynthesis inhibited formation of the extracellular matrix surrounding chondrocytes.
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| 3. |
- Abramsson, Alexandra, 1973, et al.
(författare)
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Defective N-sulfation of heparan sulfate proteoglycans limits PDGF-BB binding and pericyte recruitment in vascular development
- 2007
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Ingår i: GENES & DEVELOPMENT. - : Cold Spring Harbor Laboratory. - 0890-9369 .- 1549-5477. ; 21:3, s. 316-331
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Tidskriftsartikel (refereegranskat)abstract
- During vascular development, endothelial platelet-derived growth factor B (PDGF-B) is critical for pericyte recruitment. Deletion of the conserved C-terminal heparin-binding motif impairs PDGF-BB retention and pericyte recruitment in vivo, suggesting a potential role for heparan sulfate (HS) in PDGF-BB function during vascular development. We studied the participation of HS chains in pericyte recruitment using two mouse models with altered HS biosynthesis. Reduction of N-sulfation due to deficiency in N-deacetylase/N-sulfotransferase-1 attenuated PDGF-BB binding in vitro, and led to pericyte detachment and delayed pericyte migration in vivo. Reduced N-sulfation also impaired PDGF-BB signaling and directed cell migration, but not proliferation. In contrast, HS from glucuronyl C5-epimerase mutants, which is extensively N- and 6-O-sulfated, but lacks 2-O-sulfated L-iduronic acid residues, retained PDGF-BB in vitro, and pericyte recruitment in vivo was only transiently delayed. These observations were supported by in vitro characterization of the structural features in HS important for PDGF-BB binding. We conclude that pericyte recruitment requires HS with sufficiently extended and appropriately spaced N-sulfated domains to retain PDGF-BB and activate PDGF receptor β (PDGFRβ) signaling, whereas the detailed sequence of monosaccharide and sulfate residues does not appear to be important for this interaction.
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Bandaru, Manoj Kumar, et al.
(författare)
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Zebrafish larvae as a model system for systematic characterization of drugs and genes in dyslipidemia and atherosclerosis
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Tidskriftsartikel (refereegranskat)abstract
- Background: Hundreds of loci have been robustly associated with circulating lipids, atherosclerosis and coronary artery disease; but for most loci the causal genes and mechanisms remain uncharacterized.Methods: We developed a semi-automated experimental pipeline for systematic, quantitative, large-scale characterization of mechanisms, drugs and genes associated with dyslipidemia and atherosclerosis in a zebrafish model system. We validated our pipeline using a dietary (n>2000), drug treatment (n>1000), and genetic intervention (n=384).Results: Our results show that five days of overfeeding and cholesterol supplementation had independent pro-atherogenic effects, which could be diminished by concomitant treatment with atorvastatin and ezetimibe. CRISPR-Cas9-induced mutations in orthologues of proof-of-concept genes resulted in higher LDL cholesterol levels (apoea), and more early stage atherosclerosis (apobb.1).Conclusions: In summary, our pipeline facilitates systematic, in vivo characterization of drugs and candidate genes to increase our understanding of disease etiology, and can likely help identify novel targets for therapeutic intervention.
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| 8. |
- Banote, Rakesh Kumar, et al.
(författare)
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Amyloid precursor protein-b facilitates cell adhesion during early development in zebrafish
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the biological function of amyloid beta (A beta) precursor protein (APP) beyond its role in Alzheimer's disease is emerging. Yet, its function during embryonic development is poorly understood. The zebrafish APP orthologue, Appb, is strongly expressed during early development but thus far has only been studied via morpholino-mediated knockdown. Zebrafish enables analysis of cellular processes in an ontogenic context, which is limited in many other vertebrates. We characterized zebrafish carrying a homozygous mutation that introduces a premature stop in exon 2 of the appb gene. We report that appb mutants are significantly smaller until 2 dpf and display perturbed enveloping layer (EVL) integrity and cell protrusions at the blastula stage. Moreover, appb mutants surviving beyond 48 hpf exhibited no behavioral defects at 6 dpf and developed into healthy and fertile adults. The expression of the app family member, appa, was also found to be altered in appb mutants. Taken together, we show that appb is involved in the initial development of zebrafish by supporting the integrity of the EVL, likely by mediating cell adhesion properties. The loss of Appb might then be compensated for by other app family members to maintain normal development.
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| 9. |
- Boisvert, Catherine Anne, 1978-
(författare)
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The Origin of Tetrapod Limbs and Girdles: Fossil and Developmental Evidence
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Around 375 million years ago, the first tetrapods appeared, marking one of the most important events in vertebrate evolutionary history. The fin to limb transition saw the appearance of fingers and a weight bearing pelvic girdle. While very little research has been done on the evolution of the tetrapod pelvic girdle, a fair amount has been done on the origins of fingers but some aspects remained controversial. A combination of palaeontology, developmental biology and comparative morphology was therefore used in this thesis to better understand the fin to limb transition. The pectoral fin of Panderichthys, a sarcopterygian fish closely related to tetrapods was CT-scanned and modeled in three dimensions and its pelvic girdle and fin were examined with traditional techniques. This information from the fossil record was integrated with comparisons of the development of the Australian lungfish, Neoceratodus forsteri, our closest living fish relative and the axolotl (Ambystoma mexicanum), a salamander representing well the condition of early tetrapods. Development of bone and cartilage was studied through clearing and staining and development of skeletal muscles through immunostaining. In situ hybridizations were performed on the lungfish to study the expression of Hoxd13, associated with the formation of digits in tetrapods. This work shows that the late expression phase of Hoxd13 is present in Neoceratodus and is associated with the formation of radials. Redescription of the pectoral fin of Panderichthys reveals that distal radials are present, which, in addition to other information, lead us to conclude that digits are not novelties in tetrapods but rather have evolved from the distal radials present in the fins of all sarcopterygian fish. The earliest tetrapods lack a full set of wrist + carpals/ankle + tarsal bones. Here, we propose that this region of the limbs evolved after fingers and toes through an expansion of the region between the proximal limb bones and the digits. As for the pelvic girdle, it is very primitive in Panderichthys but comparison of its development in Neoceratodus and Ambystoma suggest that the ischium evolved through the posterior expansion of the pubis and the ilium, through an elongation of the iliac process already present in sarcopterygian fishes. The results of this thesis help to better understand the fin to limb transition and show that it is more gradual than previously believed.
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| 10. |
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| 11. |
- Dahlman, Joakim, 1974-, et al.
(författare)
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Performance and Autonomic Responses during Motion Sickness
- 2009
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Ingår i: Human Factors. - : SAGE Publications. - 0018-7208 .- 1547-8181. ; 51:1, s. 56-66
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of the study was to investigate how motion sickness, triggered by an optokinetic drum, affects short term memory performance and to explore autonomic responses to perceived motion sickness. Background: Previous research has found motion sickness to decrease performance, but it is not known how short term memory in particular is affected. Method: Thirty-eight healthy participants performed a listening span test while seated in a rotating optokinetic drum. Measurements of motion sickness, performance, heart rate, skin conductance, blood volume pulse, and pupil size were performed simultaneously throughout the experiment. Results: A total of 16 participants terminated the trial due to severe nausea, while the other 22 endured the full 25 minutes. Perceived motion sickness increased over time in both groups, but less among those who endured the trial. Short term memory performance decreased towards the end for those who terminated, while it increased for the other group. Results from the measured autonomic responses were ambiguous. Conclusion: The present study concludes that performance, measured as short term memory, declines as perceived motion sickness progresses. Application: This research has potential implications for command and control personnel in risk of developing motion sickness.
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| 12. |
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| 13. |
- Filipek-Górniok, Beata, 1983-
(författare)
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Glycosaminoglycan Biosynthesis in Zebrafish
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Proteoglycans (PGs) are composed of highly sulfated glycosaminoglycans chains (GAGs) attached to specific core proteins. They are present in extracellular matrices, on the cell surface and in storage granules of hematopoietic cells. Heparan sulfate (HS) and chondroitin/dermatan sulfate (CS/DS) GAGs play indispensable roles in a wide range of biological processes, where they can serve as protein carriers, be involved in growth factor or morphogen gradient formation and act as co-receptors in signaling processes. Protein binding abilities of GAGs are believed to be predominantly dependent on the arrangement of the sugar modifications, sulfation and epimerization, into specific oligosaccharide sequences. Although the process of HS and CS/DS assembly and modification is not fully understood, a set of GAG biosynthetic enzymes have been fairly well studied and several mutations in genes encoding for this Golgi machinery have been linked to human genetic disorders.This thesis focuses on the zebrafish N-deacetylase/N-sulfotransferase gene family, encoding key enzymes in HS chain modification, as well as glycosyltransferases responsible for chondroitin/dermatan sulfate elongation present in zebrafish. Our data illustrates the strict spatio-temporal expression of both the NDST enzymes (Paper I) and CS/DS glycosyltransferases (Paper II) in the developing zebrafish embryo. In Paper III we took advantage of the four preexisting zebrafish mutants with defective GAG biosynthesis. We could demonstrate a relation between HS content and the severity of the pectoral fin defects, and additionally correlate impaired HS biosynthesis with altered chondrocyte intercalation. Interestingly, altered CS biosynthesis resulted in loss of the chondrocyte extracellular matrix. One of the main findings was the demonstration of the ratio between the HS biosynthesis enzyme Extl3 and the Csgalnact1/Csgalnact2 proteins, as a main factor influencing the HS/CS ratio. In Paper IV we used the newly developed CRISPR/Cas9 technique to create a collection of zebrafish mutants with defective GAG biosynthetic machineries. Lack of phenotypes linked to null-mutations of most of the investigated genes is striking in this study.
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| 14. |
- Filipek-Gorniok, Beata, et al.
(författare)
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The Ndst Gene Family in Zebrafish : Role of Ndst1b in Pharyngeal Arch Formation
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Heparan sulfate (HS) proteoglycans are ubiquitous components of the extracellular matrix and plasma membrane of metazoans. The sulfation pattern of the HS glycosaminoglycan chain is characteristic for each tissue and changes during development. The glucosaminyl N-deacetylase/N-sulfotransferase (NDST) enzymes catalyze N-deacetylation and N-sulfation during HS biosynthesis and have a key role in designing the sulfation pattern. We here report on the presence of five NDST genes in zebrafish. Zebrafish ndst1a, ndst1b, ndst2a and ndst2b represent duplicated mammalian orthologues of NDST1 and NDST2 that arose through teleost specific genome duplication. Interestingly, the single zebrafish orthologue ndst3, is equally similar to tetrapod Ndst3 and Ndst4. It is likely that a local duplication in the common ancestor of lobe-finned fish and tetrapods gave rise to these two genes. All zebrafish Ndst genes showed distinct but partially overlapping expression patterns during embryonic development. Morpholino knockdown of ndst1b resulted in delayed development, craniofacial cartilage abnormalities, shortened body and pectoral fin length, resembling some of the features of the Ndst1 mouse knockout.
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| 15. |
- Fischer, Sabine, et al.
(författare)
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Zebrafish Ext2 is necessary for Fgf and Wnt signaling, but not for Hh signaling
- 2011
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Ingår i: BMC Developmental Biology. - 1471-213X. ; 11, s. 53-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Heparan sulfate (HS) biosynthesis is tightly regulated during vertebrate embryo development. However, potential roles for HS biosynthesis in regulating the function of paracrine signaling molecules that bind to HS are incompletely understood.Results: In this report we have studied Fgf, Wnt and Hedgehog (Hh) signaling in ext2 mutants, where heparan sulfate content is low. We found that Fgf targeted gene expression is reduced in ext2 mutants and that the remaining expression is readily inhibited by SU5402, an FGF receptor inhibitor. In the ext2 mutants, Fgf signaling is shown to be affected during nervous system development and reduction of Fgf ligands in the mutants affects tail development. Also, Wnt signaling is affected in the ext2 mutants, as shown by a stronger phenotype in ext2 mutants injected with morpholinos that partially block translation of Wnt11 or Wnt5b, compared to injected wild type embryos. In contrast, Hh dependent signaling is apparently unaffected in the ext2 mutants; Hh targeted gene expression is not reduced, the Hh inhibitor cyclopamine is not more affective in the mutants and Hh dependent cell differentiation in the retina and in the myotome are normal in ext2 mutants. In addition, no genetic interaction between ext2 and shha during development could be detected.Conclusion: We conclude that ext2 is involved in Fgf and Wnt signaling but not in Hh signaling, revealing an unexpected specificity for ext2 in signaling pathways during embryonic development. Thus, our results support the hypothesis that regulation of heparan sulfate biosynthesis has distinct instructive functions for different signaling factors.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
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| 20. |
- Förstberg, Johan, 1949-, et al.
(författare)
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Influence of different conditions of tilt compensation on motion and motion-related discomfort in high speed trains
- 1998
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Ingår i: Vehicle System Dynamics. - : Swets & Zeitlinger. - 0042-3114 .- 1744-5159. ; 29, s. 729-734
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Tidskriftsartikel (refereegranskat)abstract
- Train speed may be increased by constructing new railways with improved curve geometry or by using tilting trains. The tilting system compensates the lateral acceleration felt by the passengers in curves by tilting the car body, thus allowing trains to run 25-30 % faster on existing curved tracks with maintained good ride comfort. Although motion sickness in tilting trains seems to be a small problem for most passengers it can be a problem to those prone to nausea. To investigate the incidence of motion related discomfort and how different tilt compensation strategies influence the occurrence of such discomfort, a full-scale test ride was conducted on a curved track with a tilting train. Seventy healthy volunteers were employed, selected for high subjective sensitivity to nausea. Three conditions were tested using three different cars under three days. The test ride lasted about 3 hours. Four times per test ride the subjects answered a questionnaire concerning vegetative symptoms, fatigue, sleepiness and nausea. The test persons' overall estimation of average ride comfort was good in all conditions, however, some persons reported motion related discomfort due to motion sickness. A 55% degree of tilt compensation of the lateral acceleration (in the track plane) instead of the normal 70%, reduced the number of test persons reporting dizziness and nausea by about 30 - 50%. Discomfort correlates very poorly with a motion dose (time integrated) of vertical acceleration but instead correlates better with a motion dose of roll angle acceleration.
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| 21. |
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| 22. |
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| 23. |
- Gjessing, Kristian, 1967-
(författare)
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Impact of medical and non-medical Factors on Quality and Costs in Primary Care : A Conscious Look at Subconcious Processes
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background / IntroductionPhysicians and patients may be influenced by more than just the medical facts of the situation at hand. The physician is a part of the sociocultural environment and is under influence of this. The physician could be afraid of making mistakes and thus choose the safest option. In addition, economic considerations may apply. The perceived continuity or quality of the communication may also influence medical decision-making. Patients may not think about what allergens they are exposed to. Differences in socioeconomy or perceived morbidity may influence the patient's or their family’s desire to see the doctor or to use medications like antibiotics.Material and MethodsIn Paper 1, referrals from two Primary Healthcare centers in Norway were compared to each other and to the other referrals that were received by the local hospital. In Paper 2, Influenza-Like Illness (ILI) for children 2-12 years old was monitored for 7 years, and costs of treatment and parental absence due to ill children were calculated using real numbers. In Paper 3, the number of antibiotic prescriptions was compared to the patient’s socioeconomic background, to investigate possible inequalities. Paper 4 compares asthma and atopy incidence to the number of antibiotic prescriptions, to investigate if asthma patients are more often treated with antibiotics than nonasthma patients are. The analyses are based on regional healthcare data and the prospective ABIS study.ResultsPaper 1 showed that locum doctors and regular General Practitioners had the same referral rates, but the locum doctors had a distribution of diagnoses that differed significantly from the regular GPs and from the other referrals.Paper 2 showed that parental absence due to children with ILI follows the seasonal influenza pattern closely. The main burden of consultations and costs is carried by Primary Care.Paper 3 showed that parent-reported infectious morbidity at age 5, is associated with a higher number of antibiotic prescriptions in later childhood (5-14 years). Family income is a factor, where children from Q1 (wealthiest) receive significantly fewer antibiotics than children from Q3-Q5.Paper 4 found that asthma/ fur allergy at age 5 was associated with more antibiotic prescriptions in later childhood, but that wide-spectrum antibiotics are rarely used. Doctors seem to adhere to national and regional guidelines.ConclusionsPrimary care physicians seem to be affected by their grade of continuity and length of employment in their referral diagnosis distribution. Influenza-like illness in children carries a substantial cost in terms of loss of production, healthcare encounters, and personal suffering for vulnerable individuals. Parents’ perceptions of morbidity seem to influence antibiotic demand in children, along with socioeconomic factors. Children with asthma or airway allergies seem to receive more antibiotic prescriptions, possibly due to increased infectious vulnerability or to allergic exposure unknown to the doctor.
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| 24. |
- Gorniok, Beata Filipek, et al.
(författare)
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Heparan Sulfate Biosynthesis in Zebrafish
- 2021
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Ingår i: Journal of Histochemistry and Cytochemistry. - LONDON ENGLAND : SAGE Publications. - 0022-1554 .- 1551-5044. ; 69:1, s. 49-60
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Forskningsöversikt (refereegranskat)abstract
- The biosynthesis of heparan sulfate (HS) proteoglycans occurs in the Golgi compartment of cells and will determine the sulfation pattern of HS chains, which in turn will have a large impact on the biological activity of the proteoglycans. Earlier studies in mice have demonstrated the importance of HS for embryonic development. In this review, the enzymes participating in zebrafish HS biosynthesis, along with a description of enzyme mutants available for functional studies, are presented. The consequences of the zebrafish genome duplication and maternal transcript contribution are briefly discussed as are the possibilities of CRISPR/Cas9 methodologies to use the zebrafish model system for studies of biosynthesis as well as proteoglycan biology.
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| 25. |
- Gorniok, Beata Filipek, et al.
(författare)
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The Nordic Zebrafish and Husbandry Meeting 2018
- 2019
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Ingår i: Zebrafish. - : MARY ANN LIEBERT, INC. - 1545-8547 .- 1557-8542. ; 16:3, s. 329-330
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The Nordic zebrafish and husbandry meeting took place at Karolinska Institutet in Stockholm, November 7-9, 2018. More than 120 scientists from Europe joined this meeting, which also attracted world-leading keynote speakers such as Zoltan Varga, Didier Stainier, and Hernan Lopez-Schier. The meeting comprised both scientific as well as zebrafish husbandry and animal welfare sessions. This combination led to fruitful discussions, new collaborations as well as in the formation of a working group that will review and compile evidence-based husbandry guidelines for the local authorities. The success of this meeting emphasizes in general that smaller local conferences provide an excellent platform to establish local networks, to build up and share local infrastructures as well as to provide knowledge and help to peer researchers.
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