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- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Aucott, Rebecca, et al.
(författare)
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HP1-beta is required for development of the cerebral neocortex and neuromuscular junctions
- 2008
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Ingår i: Journal of Cell Biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 183:4, s. 597-606
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Tidskriftsartikel (refereegranskat)abstract
- HP1 proteins are thought to be modulators of chromatin organization in all mammals, yet their exact physiological function remains unknown. In a first attempt to elucidate the function of these proteins in vivo, we disrupted the murine Cbx1 gene, which encodes the HP1-beta isotype, and show that the Cbx1(-/-) null mutation leads to perinatal lethality. The newborn mice succumbed to acute respiratory failure, whose likely cause is the defective development of neuromuscular junctions within the endplate of the diaphragm. We also observe aberrant cerebral cortex development in Cbx1(-/-) mutant brains, which have reduced proliferation of neuronal precursors, widespread cell death, and edema. In vitro cultures of neurospheres from Cbx1(-/-) mutant brains reveal a dramatic genomic instability. Our results demonstrate that HP1 proteins are not functionally redundant and that they are likely to regulate lineage-specific changes in heterochromatin organization.
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| 3. |
- Mittendorfer, Margareta, et al.
(författare)
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Restoring discarded porcine lungs by ex vivo removal of neutrophil extracellular traps
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Ingår i: The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation. - 1557-3117.
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: By causing inflammation and tissue damage, neutrophil extracellular traps (NETs) constitute an underlying mechanism of aspiration-induced lung injury, a major factor of the low utilization of donor lungs in lung transplantation (LTx).METHOD: To determine whether NET removal during ex vivo lung perfusion (EVLP) can restore lung function and morphology in aspiration-damaged lungs, gastric aspiration lung injury was induced in 12 pigs. After confirmation of acute respiratory distress syndrome, the lungs were explanted and assigned to NET removal connected to EVLP (treated) (n=6) or EVLP only (non-treated) (n=6). Hemodynamic measurements were taken, and blood and tissue samples were collected to assess lung function, morphology, levels of cell-free DNA, extracellular histones, and nucleosomes as markers of NETs as well as cytokine levels.RESULTS: After EVLP and NET removal in porcine lungs, PaO 2/FiO 2 ratios increased significantly compared to those undergoing EVLP alone (p=0.0411). Treated lungs had lower cell-free DNA (p=0.0260) and lower levels of extracellular histones in EVLP perfusate than non-treated lungs (p=0.0260). According to histopathology, treated lungs showed less immune cell infiltration and less oedema compared with non-treated lungs which was reflected in decreased levels of pro-inflammatory cytokines in EVLP perfusate and BALF. CONCLUSION: To conclude, removing NETs during EVLP improved lung function and morphology in aspiration-damaged donor lungs. The ability to remove NETs during EVLP could represent a new therapeutic approach for LTx and potentially expand the donor pool for transplantation.
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