| 1. |
- Abbasi, M
(författare)
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First person - Marjan Abbasi
- 2022
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Ingår i: BIOLOGY OPEN. - : The Company of Biologists. - 2046-6390. ; 11:11
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- First Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping researchers promote themselves alongside their papers. Marjan Abbasi is first author on ‘ Phosphosites of the yeast centrosome component Spc110 contribute to cell cycle progression and mitotic exit’, published in BiO. Marjan is a PhD student in the lab of Victoria Menendez-Benito at the Karolinska Institutet, Bionut departement, Stockholm, Sweden, exploring the proteins involved in mitotic spindle regulation.
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| 2. |
- Ali, Zaheer, et al.
(författare)
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Adjustable delivery of pro-angiogenic FGF-2 by alginate: collagen microspheres
- 2018
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Ingår i: BIOLOGY OPEN. - : COMPANY OF BIOLOGISTS LTD. - 2046-6390. ; 7:3
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Tidskriftsartikel (refereegranskat)abstract
- Therapeutic induction of blood vessel growth (angiogenesis) in ischemic tissues holds great potential for treatment of myocardial infarction and stroke. Achieving sustained angiogenesis and vascular maturation has, however, been highly challenging. Here, we demonstrate that alginate: collagen hydrogels containing therapeutic, pro-angiogenic FGF-2, and formulated as microspheres, is a promising and clinically relevant vehicle for therapeutic angiogenesis. By titrating the amount of readily dissolvable and degradable collagen with more slowly degradable alginate in the hydrogel mixture, the degradation rates of the biomaterial controlling the release kinetics of embedded proangiogenic FGF-2 can be adjusted. Furthermore, we elaborate a microsphere synthesis protocol allowing accurate control over sphere size, also a critical determinant of degradation/release rate. As expected, alginate: collagen microspheres were completely biocompatible and did not cause any adverse reactions when injected in mice. Importantly, the amount of pro-angiogenic FGF-2 released from such microspheres led to robust induction of angiogenesis in zebrafish embryos similar to that achieved by injecting FGF-2-releasing cells. These findings highlight the use of microspheres constructed from alginate: collagen hydrogels as a promising and clinically relevant delivery system for pro-angiogenic therapy.
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| 3. |
- Andrae, Johanna, et al.
(författare)
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A role for PDGF-C/PDGFR alpha signaling in the formation of the meningeal basement membranes surrounding the cerebral cortex
- 2016
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Ingår i: Biology Open. - : The Company of Biologists. - 2046-6390. ; 5:4, s. 461-474
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Tidskriftsartikel (refereegranskat)abstract
- Platelet-derived growth factor-C (PDGF-C) is one of three known ligands for the tyrosine kinase receptor PDGFR alpha. Analysis of Pdgfc null mice has demonstrated roles for PDGF-C in palate closure and the formation of cerebral ventricles, but redundancy with other PDGFR alpha ligands might obscure additional functions. In search of further developmental roles for PDGF-C, we generated mice that were double mutants for Pdgfc(-/-) and Pdgfra(GFP/+). These mice display a range of severe phenotypes including spina bifida, lung emphysema, abnormal meninges and neuronal over-migration in the cerebral cortex. We focused our analysis on the central nervous system (CNS), where PDGF-C was identified as a critical factor for the formation of meninges and assembly of the glia limitans basement membrane. We also present expression data on Pdgfa, Pdgfc and Pdgfra in the cerebral cortex and microarray data on cerebral meninges.
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| 4. |
- Arnés, Mercedes, et al.
(författare)
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Amyloid β42 peptide is toxic to non-neural cells in Drosophila yielding a characteristic metabolite profile and the effect can be suppressed by PI3K
- 2017
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Ingår i: Biology Open. - : The Company of Biologists. - 2046-6390. ; 6:11, s. 1664-1671
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Tidskriftsartikel (refereegranskat)abstract
- The human Aβ42 peptide is associated with Alzheimer’s disease through its deleterious effects in neurons. Expressing the human peptide in adult Drosophila in a tissue- and time-controlled manner, we show that Aβ42 is also toxic in non-neural cells, neurosecretory and epithelial cell types in particular. This form of toxicity includes the aberrant signaling by Wingless morphogen leading to the eventual activation of Caspase 3. Preventing Caspase 3 activation by means of p53 keeps epithelial cells from elimination but maintains the Aβ42 toxicity yielding more severe deleterious effects to the organism. Metabolic profiling by nuclear magnetic resonance (NMR) of adult flies at selected ages post Aβ42 expression onset reveals characteristic changes in metabolites as early markers of the pathological process. All morphological and most metabolic features of Aβ42 toxicity can be suppressed by the joint overexpression of PI3K.
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| 5. |
- Baccino-Calace, Martin, et al.
(författare)
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Compartment and cell-type specific hypoxia responsesin the developing Drosophila brain
- 2020
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Ingår i: Biology Open. - : The Company of Biologists. - 2046-6390. ; 9:8
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Tidskriftsartikel (refereegranskat)abstract
- Environmental factors such as the availability of oxygen are instructive cues that regulate stem cell maintenance and differentiation. We used a genetically encoded biosensor to monitor the hypoxic state of neural cells in the larval brain of Drosophila. The biosensor reveals brain compartment and cell-type specific levels of hypoxia. The values correlate with differential tracheolation that is observed throughout development between the central brain and the optic lobe. Neural stem cells in both compartments show the strongest hypoxia response while intermediate progenitors, neurons and glial cells reveal weaker responses. We demonstrate that the distance between a cell and the next closest tracheole is a good predictor of the hypoxic state of that cell. Our study indicates that oxygen availability appears to be the major factor controlling the hypoxia response in the developing Drosophila brain and that cell intrinsic and cell-type specific factors contribute to modulate the response in an unexpected manner.
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| 6. |
- Bergkvist, Liza, et al.
(författare)
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A beta PP processing results in greater toxicity per amount of A beta(1-42) than individually expressed and secreted A beta(1-42) in Drosophila melanogaster
- 2016
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Ingår i: BIOLOGY OPEN. - : COMPANY OF BIOLOGISTS LTD. - 2046-6390. ; 5:8, s. 1030-1039
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Tidskriftsartikel (refereegranskat)abstract
- The aggregation of the amyloid-beta (A beta) peptide into fibrillar deposits has long been considered the key neuropathological hallmark of Alzheimers disease (AD). A beta peptides are generated from proteolytic processing of the transmembrane A beta precursor protein (A beta PP) via sequential proteolysis through the beta-secretase activity of beta-site A beta PP-cleaving enzyme (BACE1) and by the intramembranous enzyme gamma-secretase. For over a decade, Drosophila melanogaster has been used as a model organism to study AD, and two different approaches have been developed to investigate the toxicity caused by AD-associated gene products in vivo. In one model, the A beta peptide is directly over-expressed fused to a signal peptide, allowing secretion of the peptide into the extracellular space. In the other model, human A beta PP is co-expressed with human BACE1, resulting in production of the A beta peptide through the processing of A beta PP by BACE1 and by endogenous fly gamma-secretase. Here, we performed a parallel study of flies that expressed the A beta(1-42) peptide alone or that co-expressed A beta PP and BACE1. Toxic effects (assessed by eye phenotype, longevity and locomotor assays) and levels of the A beta(1-42), A beta(1-40) and A beta(1-38) peptides were examined. Our data reveal that the toxic effect per amount of detected A beta(1-42) peptide was higher in the flies co-expressing A beta PP and BACE1 than in the A beta(1-42)-expressing flies, and that the co-existence of A beta(1-42) and A beta(1-40) in the flies co-expressing A beta PP and BACE1 could be of significant importance to the neurotoxic effect detected in these flies. Thus, the toxicity detected in these two fly models seems to have different modes of action and is highly dependent on how and where the peptide is generated rather than on the actual level of the A beta(1-42) peptide in the flies. This is important knowledge that needs to be taken into consideration when using Drosophila models to investigate disease mechanisms or therapeutic strategies in AD research.
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| 7. |
- Burness, Gary, et al.
(författare)
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Maternal immunization increases nestling energy expenditure, immune function, and fledging success in a passerine bird
- 2018
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Ingår i: Biology Open. - : The Company of Biologists. - 2046-6390. ; 7:4
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Tidskriftsartikel (refereegranskat)abstract
- Female birds transfer maternally derived antibodies (matAb) to their nestlings, via the egg yolk. These antibodies are thought to provide passive protection, and allow nestlings to avoid the costs associated with mounting an innate immune response. To test whether there is an energetic benefit to nestlings from receiving matAb, we challenged adult female tree swallows (Tachycineta bicolor) prior to clutch initiation with either lipopolysaccharide (LPS) or saline (Control). Following hatching, one half of each female's nestlings were immunized on day 8 post-hatch with LPS or saline, and the 4-h post-immunization nestling metabolic rate (MR) was measured. There was no difference in either LPS-reactive antibodies or total Ig levels between offspring of immunized and non-immunized mothers on day 6 or 14 post-hatch, possibly reflecting a relatively short half-life of matAbs in altricial birds. Additionally, we found no evidence that nestlings from LPS-immunized mothers could avoid the growth suppression that may result from activation of an inflammatory response. Unexpectedly, we found that control nestlings from LPS mothers had higher resting MR than control nestlings of control mothers.We attribute the increasedMR to the costs associated with a general non-specific enhancement of immune function in nestlings from LPS-immunized mothers. Consistent with enhanced immune function, nestlings of immunized mothers had a more robust inflammatory response to phytohaemagglutinin and higher fledging success. Our results suggest that maternal antigen exposure prelaying can result in increased fitness for both mothers and offspring, depending on food availability.
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| 8. |
- Carney Almroth, Bethanie, 1974, et al.
(författare)
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Gender differences in health and aging of Atlantic cod subject to size selective fishery
- 2012
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Ingår i: Biology Open. - : The Company of Biologists. - 2046-6390. ; 1:9, s. 922-928
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Tidskriftsartikel (refereegranskat)abstract
- We have analyzed health and physiological aging parameters in male and female Atlantic cod, Gadus morhua, captured in Kattegat, Skagerrak and in Öresund. Gender differences were clearly evident in a number of variables. Males had longer liver telomeres and higher catalase activities than females, while females had higher superoxide dismutase activity, liver somatic index and condition factor. Effects of age were found for males where levels of the antioxidant glutathione and telomere length declined with age, indicating physiological aging. Liver somatic index increased and percentage oxidized glutathione decreased with age. Between-site comparisons of males show that percentage oxidized glutathione and catalase were lowest in Kattegat, whereas protein carbonyls and condition factor were higher in Skagerrak. Females, on the other hand, showed no differences between sites or indications of somatic aging or age-related effects in egg quality, indicating that older and larger female cod are healthy and show no changes in eggs with age. In contrast, males showed indications of physiological aging and lower condition than females. The results emphasize the importance of conserving old mature fish, in particular high egg-productive females, when managing fisheries.
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| 9. |
- Chaib, Sandra, et al.
(författare)
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Visual acuity of budgerigars for moving targets
- 2021
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Ingår i: Biology Open. - : The Company of Biologists. - 2046-6390. ; 10:9
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Tidskriftsartikel (refereegranskat)abstract
- For a bird, it is often vital to visually detect food items, predators, or individuals from the same flock, i.e. moving stimuli of various shapes. Yet, behavioural tests of visual spatial acuity traditionally use stationary gratings as stimuli. We have behaviourally tested the ability of budgerigars (Melopsittacus undulatus) to detect a black circular target, moving semi-randomly at 1.69 degrees s−1 against a brighter background. We found a detection threshold of 0.107±0.007 degrees of the visual field for a target size corresponding to a resolution of a grating with a spatial frequency of 4.68 cycles degree−1. This detection threshold is lower than the resolution limit for gratings but similar to the threshold for stationary single objects of the same shape. We conclude that the target acuity of budgerigars for moving single targets, just as for stationary single targets, is lower than their acuity for gratings.
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| 10. |
- Chen, Haiqiong, et al.
(författare)
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Hansenula polymorpha cells lacking the ER-localized peroxins Pex23 or Pex29 show defects in mitochondrial function and morphology
- 2024
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Ingår i: Biology Open. - 2046-6390. ; 13:5
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Tidskriftsartikel (refereegranskat)abstract
- Pex23 family proteins localize to the endoplasmic reticulum and play a role in peroxisome and lipid body formation. The yeast Hansenula polymorpha contains four members: Pex23, Pex24, Pex29 and Pex32. We previously showed that loss of Pex24 or Pex32 results in severe peroxisomal defects, caused by reduced peroxisomeendoplasmic reticulum contact sites. We now analyzed the effect of the absence of all four Pex23 family proteins on other cell organelles. Vacuoles were normal in all four deletion strains. The number of lipid droplets was reduced in pex23 and pex29 , but not in pex24 and pex32 cells, indicating that peroxisome and lipid droplet formation require different Pex23 family proteins in H. polymorpha . In pex23 and pex29 cells mitochondria were fragmented and clustered accompanied by reduced levels of the fusion protein Fzo1. Deletion of DNM1 suppressed the morphological phenotype of pex23 and pex29 cells, suggesting that mitochondrial fusion is affected. pex23 and pex29 cells showed retarded growth and reduced mitochondrial activities. The growth defect was partially suppressed by DNM1 deletion as well as by an artificial mitochondrion-endoplasmic reticulum tether. Hence, the absence of Pex23 family proteins may influence mitochondrion-endoplasmic reticulum contact sites.
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