Monomeric Garnet, a far-red fluorescent protein for live-cell STED imaging

The advancement of far-red emitting variants of the green fluorescent protein (GFP) is crucially important for imaging live cells, tissues and organisms. Despite notable efforts, far-red marker proteins still need further optimization to match the performance of their green counterparts. Here we present mGarnet, a robust monomeric marker protein with far-red fluorescence peaking at 670 nm. Thanks to its large extinction coefficient of 95,000 M-1 cm-1, mGarnet can be efficiently excited with 640-nm light on the red edge of its 598-nm excitation band. A large Stokes shift allows essentially the entire fluorescence emission to be collected even with 640-nm excitation, counterbalancing the lower fluorescence quantum yield of mGarnet, 9.1%, that is typical of far-red FPs. We demonstrate an excellent performance as a live-cell fusion marker in STED microscopy, using 640 nm excitation and 780 nm depletion wavelengths

Measuring ligand-cell surface receptor affinities with axial line-scanning fluorescence correlation spectroscopy

Development and homeostasis of multicellular organisms is largely controlled by complex cell-cell signaling networks that rely on specific binding of secreted ligands to cell surface receptors. The Wnt signaling network, as an example, involves multiple ligands and receptors to elicit specific cellular responses. To understand the mechanisms of such a network, ligand-receptor interactions should be characterized quantitatively, ideally in live cells or tissues. Such measurements are possible using fluorescence microscopy yet challenging due to sample movement, low signal-to-background ratio and photobleaching. Here, we present a robust approach based on fluorescence correlation spectroscopy with ultra-high speed axial line scanning, yielding precise equilibrium dissociation coefficients of interactions in the Wnt signaling pathway. Using CRISPR/Cas9 editing to endogenously tag receptors with fluorescent proteins, we demonstrate that the method delivers precise results even with low, near-native amounts of receptors

Complex RNA folding kinetics revealed by single molecule FRET and hidden Markov models

We have developed a hidden Markov model and optimization procedure for photon-based single- molecule FRET data, which takes into account the trace-dependent background intensities. This analysis technique reveals an unprecedented amount of detail in the folding kinetics of the Diels-Alderase ribozyme. We find a multitude of extended (low-FRET) and compact (high-FRET) states. Five states were consistently and independently found in two FRET constructs and three Mg2+ concentrations. Structures generally tend to become more compact upon addition of Mg2+. Some compact structures are found to significantly depend on Mg2+ concentration, suggesting a tertiary fold stabilized by Mg2+ ions. One compact structure was found to be Mg2+-independent, consistent with stabilization by tertiary Watson-Crick base pairing found in the folded Diels-Alderase structure. A hierarchy of timescales was found, including dynamics of 10 ms or faster, likely due to tertiary structure fluctuations, and slow dynamics on the seconds timescale, presumably associated with significant changes in secondary structure. The folding pathways proceed through a series of intermediate secondary structures. There exist both, compact pathways and more complex ones, which display tertiary unfolding, then secondary refolding and, subsequently, again tertiary refolding

Standardized assessment of psychosocial factors and their influence on medically confirmed health outcomes in workers: a systematic review

Findings on health-related work outcomes [28–37]. (DOCX 27.8 kb

The Portuguese long version of the Copenhagen Psychosocial Questionnaire II (COPSOQ II) - a validation study

BACKGROUND: Psychosocial risks are now widely recognised as one of the biggest challenges for occupational safety and health (OSH) and a major public health concern. The aim of this paper is to investigate the Portuguese long version of the Copenhagen Psychosocial Questionnaire II (COPSOQ II), in order to analyse the psychometric properties of the instrument and to validate it. METHODS: The Portuguese COPSOQ II was issued to a total of 745 Portuguese employees from both private and public organisations across several economic sectors at a baseline and then 2 weeks later. Methodological quality appraisal was based on COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) recommendations. An analysis of the psychometric properties of the long version of COPSOQ II (internal consistency, intraclass correlation coefficient, floor and ceiling effects, response rate, missing values, mean and standard deviation, exploratory factor analysis) was performed to determine the validity and reliability of the instrument. RESULTS: The COPSOQ II had a response rate of 60.6% (test) and a follow-up response rate of 59.5% (retest). In general, a Cronbach's alpha of the COPSOQ scales (test and retest) was above the conventional threshold of 0.70. The test-retest reliability estimated by the intraclass correlation coefficient (ICC) showed a higher reliability for most of the scales, above the conventional 0.7, except for eight scales. The proportion of the missing values was less than 1.3%, except for two scales. The average scores and standard deviations showed similar results to the original Danish study, except for eight scales. All of the scales had low floor and ceiling effects, with one exception. Overall, the exploratory factor analysis presented good results in 27 scales assuming a reflective measurement model. The hypothesized factor structure under a reflective model was not supported in 14 scales and for some but not all of these scales the explanation may be a formative measurement model. CONCLUSION: The Portuguese long version of COPSOQ II is a reliable and valid instrument for assessing psychosocial risks in the workplace. Although the results are good for most of the scales, there are those that should be evaluated in greater depth in future studies. This instrument may contribute to the promotion of a healthy working environment and workforce, providing clear benefits for companies and employees.info:eu-repo/semantics/publishedVersio

Bidirectional Assessment of Stress, job satisfaction and work ability of Educators in day care centres: a real-time observation study - the study protocol (BASE)

Background: Occupational demands of educators are not very well researched. Nevertheless their work is subject to several requirements. Whether these demands have an effect on the work ability and the health status of employees has also not been examined. Furthermore it is unclear if the ownership type of day care centres have an influence on job satisfaction and work ability of the pedagogical staff and what kind of resources do exist. Previous studies were mainly based on questionnaire data. Objective data does not exist. Therefore the aim of this investigation is to collect precise data relating to work of educators. Methods: Effects of different types of ownership of day care centres on job satisfaction and work ability of educators will be assessed with the help of objective real time studies in combination with multi-level psycho diagnostic measurements. Discussion: The present study is the first of its kind. Up to now there are no computer-based real time studies on workflow of pedagogical staff with regard to assess their work-related stress. Following an exhaustive documentation of educators work processes the day-to-day task can be estimated and approaches for prevention can be developed. This can substantially contribute to an overall improvement of child care in Germany