Ralstonia eutropha JMP134 carries a 22 kb DNA region on plasmid pJP4 necessary for the degradation of 2,4-D (2,4-dichlorophenoxyacetate). In this study, expression of the 2,4-D pathway genes (designated tfd ) upon exposure to different concentrations of 2,4-D was measured at a detailed timescale in chemostat-grown R. eutropha cultures. A sharp increase in mRNA levels for tfdA, tfdCDEF-B, tfdDIICIIEIIFII-BII and tfdK was detected between 2 and 13 min after exposure to 2,4-D. This response time was not dependent on the 2,4-D concentration. The genes tfdA, tfdCD and tfdDIICII were expressed immediately upon induction, whereas tfdB, tfdBII and tfdK mRNAs could be detected only around 10 min later. The number of tfd mRNA transcripts per cell was estimated to be around 200-500 during maximal expression, after which they decreased to between 1 and 30 depending on the 2,4-D concentration used for induction. Unlike the mRNAs, the specific activity of the 2,4-D pathway enzyme chlorocatechol 1,2-dioxygenase did not increase sharply but accumulated to a steady-state plateau, which was dependent on the 2, 4-D concentration in the medium. At 1 mM 2,4-D, several oscillations in mRNA levels were observed before steady-state expression was reached, which was caused by transient accumulation of the first pathway intermediate, 2,4-dichlorophenol, to toxic concentrations. Expression of tfdR and tfdS, the (identical) regulatory genes for the tfd pathway remained low and essentially unchanged during the entire adaptation phase.

Background The Covid-19 pandemic led to increased work-related strain and psychosocial burden in nurses worldwide, resulting in high prevalences of mental health problems. Nurses in long-term care facilities seem to be especially affected by the pandemic. Nevertheless, there are few findings indicating possible positive changes for health care workers. Therefore, we investigated which psychosocial burdens and potential positive aspects nurses working in long-term care facilities experience during the Covid-19 pandemic. Methods We conducted a mixed-methods study among nurses and nursing assistants working in nursing homes in Germany. The survey contained the third German version of the Copenhagen Psychosocial Questionnaire (COPSOQ III). Using Welch’s t-tests, we compared the COPSOQ results of our sample against a pre-pandemic reference group of geriatric nurses from Germany. Additionally, we conducted semi-structured interviews with geriatric nurses with a special focus on psychosocial stress, to reach a deeper understanding of their experiences on work-related changes and burdens during the pandemic. Data were analysed using thematic coding (Braun and Clarke). Results Our survey sample (n = 177) differed significantly from the pre-pandemic reference group in 14 out of 31 COPSOQ scales. Almost all of these differences indicated negative changes. Our sample scored significantly worse regarding the scales ‘quantitative demands’, ‘hiding emotions’, ‘work-privacy conflicts’, ‘role conflicts’, ‘quality of leadership’, ‘support at work’, ‘recognition’, ‘physical demands’, ‘intention to leave profession’, ‘burnout’, ‘presenteeism’ and ‘inability to relax’. The interviews (n = 15) revealed six main themes related to nurses’ psychosocial stress: ‘overall working conditions’, ‘concern for residents’, ‘management of relatives’, ‘inability to provide terminal care‘, ‘tensions between being infected and infecting others’ and ‘technicisation of care’. ‘Enhanced community cohesion’ (interviews), ‘meaning of work’ and ‘quantity of social relations’ (COPSOQ III) were identified as positive effects of the pandemic. Conclusions Results clearly illustrate an aggravation of geriatric nurses’ situation and psychosocial burden and only few positive changes due to the Covid-19 pandemic. Pre-existing hardships seem to have further deteriorated and new stressors added to nurses’ strain. The perceived erosion of care, due to an overemphasis of the technical in relation to the social and emotional dimensions of care, seems to be especially burdensome to geriatric nurses.

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Background: To date, only limited magnetic resonance imaging (MRI) data are available concerning tumor regression during neoadjuvant radiochemotherapy (RCT) of rectal cancer patients, which is a prerequisite for adaptive radiotherapy (RT) concepts. This exploratory study prospectively evaluated daily fractional MRI during neoadjuvant treatment to analyze the predictive value of MR biomarkers for treatment response. Methods: Locally advanced rectal cancer patients were examined with daily MRI during neoadjuvant RCT. Contouring of the tumor volume was performed for each MRI scan by using T2-and diffusion-weighted-imaging (DWI)-sequences. The daily apparent-diffusion coefficient (ADC) was calculated. Volumetric and functional tumor changes during RCT were analyzed and correlated with the pathological response after surgical resection. Results: In total, 171 MRI scans of eight patients were analyzed regarding anatomical and functional dynamics during RCT. Pathological complete response (pCR) could be achieved in four patients, and four patients had a pathological partial response (pPR) following neoadjuvant treatment. T2-and DWI-based volumetry proved to be statistically significant in terms of therapeutic response, and volumetric thresholds at week two and week four during RCT were defined for the prediction of pCR. In contrast, the average tumor ADC values widely overlapped between both response groups during RCT and appeared inadequate to predict treatment response in our patient cohort. Conclusion: This prospective exploratory study supports the hypothesis that MRI may be able to predict pCR of rectal cancers early during neoadjuvant RCT. Our data therefore provide a useful template to tailor future MRguided adaptive treatment concepts.