| 1. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
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.
|
|
| 2. |
-
- 2019
-
Tidskriftsartikel (refereegranskat)
|
|
| 3. |
- Baez, Sofia, 1963-
(författare)
-
Dopachrome and aminochrome, the oxidized metabolites of dopa and dopamine : studies on the molecular mechanisms underlying their reduction and conjugation with glutathione
- 1999
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dopamine, like other catecholamines can be oxidized to the corresponding ortho-quinone, which undergoes cyclization of its amino chain to cyclized dopamine ortho-quinone (aminochrome). Both o-quinones are toxic metabolites that may contribute to neurotoxic effects of these catecholamines. The oxidation of dopamine to o-quinone is believed to be one of the causes of the neurodegenerative process of Parkinson's disease.Although it is in generally accepted that free radicals are involved in the neurodegenerative process occurring in the dopaminergic neuron system in Parkinson's disease, the exact mechanism of neurodegeneration in vivo is still unknown. However, one possible source of free radicals in the dopaminergic neuron system in the central nerve system may involve the oxidation of dopamine to the corresponding o-quinone.L-Dopa is commonly used in the clinical management of Parkinson's disease. However, this treatment becomes gradually ineffective, due either to loss of efficacy or to appearance of side-effects, probably produced by the oxidative injury generated by the oxidation of dopa or of its metabolites.We report in this study that the oxidation of dopa and dopamine to the corresponding o-quinone and the followed cyclization, at physiological pH, is not itself responsible for the formation of reactive oxygen species. In addition, we show that the reduction of cyclized o-quinones of dopamine and the subsequent autoxidation is the step in which reactive species are formed.Formation of reactive oxygen species during one- or two-electron reduction of aminochrome and dopachrome has been studied in vitro by using NADPH-cytochrome P450 reductase and DT-diaphorase, respectively. The results suggest that DT-diaphorase, SOD, catalase (glutathione peroxidase) and sulfotransferase constitute the cellular defenses against formation of reactive oxygen species during reduction of aminochrome and dopachrome.We also studied the ability of human glutathione transferases to conjugate cyclized catechol o-quinones such as aminochrome and dopachrome and found that GSTs, in particularly GST M2-2 catalyzes GSH conjugation of dopachrome and aminochrome, preventing the formation of ROS and reactive catechol metabolites. The neuroprotective role of GST M2-2 suggested in the present study is depend on the presence of the enzyme in relevants regions of the human brain, regions where cell damage is observed in diseases such as schizoprenia and Parkinson's disease.
|
|
| 4. |
- Bernal, Ximena E., et al.
(författare)
-
Empowering Latina scientists
- 2019
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 363:6429, s. 825-826
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 5. |
- Dahlberg, Helene, et al.
(författare)
-
The role of extreme programming in a plan-driven organization
- 2006
-
Ingår i: International Federation For Information Processing, Working Group 8.6.
-
Tidskriftsartikel (refereegranskat)abstract
- The difficulties and even lack of commitment to follow plans within plan-based organizations is a well known phenomenon (see Ciborra et al. 2000; Suchman 1987). For software development companies, this problem has become an increasing dilemma, as typically plan-driven software development assessment standards like the capability maturity model (CMM) or ISO/IEC 15504 have not always been easy to conform processes against. Particularly, in environments where requirements are rapidly changing, more agile approaches such as Scrum and extreme programming (XP) have caught on. In this work, we are reporting from a case study of an organization looking to not move completely from their plan-based processes (as they are but a part of a larger organization operating in a plan-based way), but rather adapt their overarching processes in a way that allows them to use XP to support their everyday work precluded by their current processes. To this end, we present four perspectives that organizations may take when they desire or consider becoming more agile in their development. We use the Nerur et al. (2005) key issues for moving from plan-based to agile software development to compare and analyze our findings. In doing this, we highlight a set of likely criteria necessary to successfully create a combination of the plan-driven and agile approaches.
|
|
