Red and blue light differentially impact retrograde signalling and photoprotection in rice

Chloroplast-to-nucleus retrograde signalling (RS) is known to impact plant growth and development. In Arabidopsis, we and others have shown that RS affects seedling establishment by inhibiting deetiolation. In the presence of lincomycin, a chloroplast protein synthesis inhibitor that triggers RS, Arabidopsis light-grown seedlings display partial skotomorphogenesis with undeveloped plastids and closed cotyledons. By contrast, RS in monocotyledonous has been much less studied. Here, we show that emerging rice seedlings exposed to lincomycin do not accumulate chlorophyll but otherwise remain remarkably unaffected. However, by using high red (R) and blue (B) monochromatic lights in combination with lincomycin, we have uncovered a RS inhibition of length and a reduction in the B light-induced declination of the second leaf. Furthermore, we present data showing that seedlings grown in high B and R light display different non-photochemical quenching capacity. Our findings support the view that excess B and R light impact seedling photomorphogenesis differently to photoprotect and optimize the response to high-light stres

GENOMES UNCOUPLED1-independent retrograde signaling targets the ethylene pathway to repress photomorphogenesis

Altres ajuts: CERCA Programme/Generalitat de CatalunyaWhen germinating in the light, Arabidopsis (Arabidopsis thaliana) seedlings undergo photomorphogenic development, characterized by short hypocotyls, greening, and expanded cotyledons. Stressed chloroplasts emit retrograde signals to the nucleus that induce developmental responses and repress photomorphogenesis. The nuclear targets of these retrograde signals are not yet fully known. Here, we show that lincomycin-treated seedlings (which lack developed chloroplasts) show strong phenotypic similarities to seedlings treated with ethylene (ET) precursor 1-aminocyclopropane-1-carboxylic acid, as both signals inhibit cotyledon separation in the light. We show that the lincomycin-induced phenotype partly requires a functioning ET signaling pathway, but could not detect increased ET emissions in response to the lincomycin treatment. The two treatments show overlap in upregulated gene transcripts, downstream of transcription factors ETHYLENE INSENSITIVE3 and EIN3-LIKE1. The induction of the ET signaling pathway is triggered by an unknown retrograde signal acting independently of GENOMES UNCOUPLED1. Our data show how two apparently different stress responses converge to optimize photomorphogenesis

Characterization of the GGPP synthase gene family in Arabidopsis thaliana

Geranylgeranyl diphosphate (GGPP) is a key precursor of various isoprenoids that have diverse functions in plant metabolism and development. The annotation of the Arabidopsis thaliana genome predicts 12 genes to encode geranylgeranyl diphosphate synthases (GGPPS). In this study we analyzed GGPPS activity as well as the subcellular localization and tissue-specific expression of the entire protein family in A. thaliana. GGPPS2 (At2g18620), GGPPS3 (At2g18640), GGPPS6 (At3g14530), GGPPS7 (At3g14550), GGPPS8 (At3g20160), GGPPS9 (At3g29430), GGPPS10 (At3g32040) and GGPPS11 (At4g36810) showed GGPPS activity in Escherichia coli, similar to activities reported earlier for GGPPS1 (At1g49530) and GGPPS4 (At2g23800) (Zhu et al. in Plant Cell Physiol 38(3):357-361, 1997a; Plant Mol Biol 35(3):331-341, b). GGPPS12 (At4g38460) did not produce GGPP in E. coli. Based on DNA sequence analysis we propose that GGPPS5 (At3g14510) is a pseudogene. GGPPS-GFP (green fluorescent protein) fusion proteins of the ten functional GGPP synthases localized to plastids, mitochondria and the endoplasmic reticulum, with the majority of the enzymes located in plastids. Gene expression analysis using quantitative real time-PCR, GGPPS promoter-GUS (β-glucuronidase) assays and publicly available microarray data revealed a differential spatio-temporal expression of GGPPS genes. The results suggest that plastids and mitochondria are key subcellular compartments for the synthesis of ubiquitous GGPP-derived isoprenoid species. GGPPS11 and GGPPS1 are the major isozymes responsible for their biosynthesis. All remaining paralogs, encoding six plastidial isozymes and two cytosolic isozymes, were expressed in specific tissues and/or at specific developmental stages, suggesting their role in developmentally regulated isoprenoid biosynthesis. Our results show that of the 12 predicted GGPPS encoded in the A. thaliana genome 10 are functional proteins that can synthesize GGPP. Their specific subcellular location and differential expression pattern suggest subfunctionalization in providing GGPP to specific tissues, developmental stages, or metabolic pathway

Ethical conflicts among physicians and nurses during the COVID‐19 pandemic: A qualitative study

Rationale, Aims and Objectives The healthcare system and professionals working in the sector have experienced a high caseload during the coronavirus disease 2019 (COVID-19) pandemic. This has increased the potential for morally harmful events that violate professionals' moral codes and values. The aim of this study was to understand and explore experiences of new moral challenges emerging among physicians and nurses caring for individuals during the COVID-19 pandemic. Method The consolidated criteria for reporting qualitative research (COREQ) checklist was used in this qualitative study based on Gadamer's phenomenology. Participants were selected using a convenience sampling method. Thirteen medicine and nursing graduates were interviewed in depth. The participants all worked on the frontline at the start of the COVID-19 pandemic. Data were gathered in two basic healthcare districts in Spain, encompassing both primary care and hospital care. Results Four main themes emerged from the data analysis: (1) Betrayal of moral and ethical values as a key source of suffering; (2) Ethical and moral sense of failure accompanying loss of meaning; (3) Lack of confidence in performance; (4) Self-demand and self-punishment as personal condemnation among healthcare workers. Conclusions Health institutions must implement interventions for health professionals to help mitigate the consequences of experiencing complex ethical scenarios during the pandemic. In addition, they should promote training in moral and ethical deliberation and prepare them to make decisions of great ethical significance

Occupational factors associated with health-related quality of life in nursing professionals: a multi-centre study

Background: Nursing professionals are exposed to stressful situations arising from the work context that may affect health-related quality of life (HRQoL). The objective of this study was to analyse the relationship between sociodemographic and work-related variables regarding HRQoL in nursing professionals. Methods: A multi-centre, cross-sectional descriptive design was used. The participants consisted 1521 nurses working in healthcare centres, in both primary care and hospital care, in the eight provinces of the Andalusian Public Health System (APHS), Spain. Sociodemographic and work-related variables were analysed: Compassion fatigue, compassion satisfaction and burnout were measured using the professional quality of life questionnaire (ProQOL), and HRQoL was measured using the SF-12 health questionnaire. Results: Compassion fatigue, burnou, and, to a lesser extent, compassion satisfaction significantly influence the physical and mental components of HRQoL. The simple regression analysis showed that burnout and compassion fatigue were significantly associated with the mental component of HRQoL. Gender influenced the mental component of HRQoL. The rest of the sociodemographic and work-related variables were not significantly related to HRQoL. Conclusion: Work-related stress and repeated contact with situations of suffering influence HRQoL. Health systems must implement programmes to increase the emotional well-being of workers

Predictor factors of perceived health in family caregivers of people diagnosed with mild or moderate Alzheimer's disease

Caring for a person diagnosed with Alzheimer’s disease has a negative impact on family caregivers’ psychological health. This study examined the factors related to ‘perceived health’ and ‘presence of new-onset mental health problems’ in family caregivers of people diagnosed with mild and moderate Alzheimer’s disease. A cross-sectional observational study carried out in Almeria’s Healthcare District (Spain). A total of 255 family caregivers (42.4% cared for people with mild Alzheimer’s disease and 57.6% cared for people with moderate Alzheimer’s disease) participated in the study from January to December 2015. Mainly, caregivers were women (81.5% in the mild Alzheimer’s disease group and 88.4% in the moderate Alzheimer’s disease group), and their average age was 56.54 years (standard deviation (SD) = 13.13) and 54.47 years (SD = 11.71), respectively. Around 47% of the caregivers had been caring for the person with Alzheimer’s between two and five years. The Goldberg General Health Questionnaire was used to measure perceived health and the presence of new-onset mental health problems. An exploratory descriptive analysis and a multivariate logistic regression analysis were conducted. For caregivers of people with mild Alzheimer’s disease, ‘perceived health’ was related to ‘perceived social support’ (r = −0.21; p = 0.028), ‘person’s level of dependency’ (r = −0.24, p = 0.05), ‘severity of the person’s neuropsychiatric symptoms’ (r = 0.22; p = 0.05), and ‘caregiver’s emotional distress in response to the person’s neuropsychiatric symptoms’ (r = 0.22; p = 0.05). For caregivers of people with moderate Alzheimer’s disease, ‘perceived health’ was related to ‘perceived social support’ (r = −0.31; p ˂ 0.01), ‘presence of neuropsychiatric symptoms’ (r = 0.27, p = 0.01), ‘severity of the person’s neuropsychiatric symptoms’ (r = 0.32, p = 0.01) and ‘caregiver’s emotional distress in response to the person’s neuropsychiatric symptoms’ (r = 0.029; p = 0.01). The presence of new-onset mental health problems was detected in 46.3% (n = 50) of caregivers of people with mild Alzheimer’s and 61.9% (n = 91) of caregivers of people with moderate Alzheimer’s. When people are diagnosed with mild Alzheimer’s disease, intervention programs for caregivers should aim to regulate emotions and promote positive coping strategies. When people are diagnosed with moderate Alzheimer’s disease, intervention programs for caregivers must allow them to adapt to caregiving demands that arise with the progression of Alzheimer’s disease

Design and psychometric analysis of the COVID-19 prevention, recognition and home-management self-efficacy scale

In order to control the spread of COVID-19, people must adopt preventive behaviours that can affect their day-to-day life. People’s self-efficacy to adopt preventive behaviours to avoid COVID-19 contagion and spread should be studied. The aim of this study was to develop and psychometrically test the COVID-19 prevention, detection, and home-management self-efficacy scale (COVID-19-SES). We conducted an observational cross-sectional study. Six-hundred and seventy-eight people participated in the study. Data were collected between March and May 2020. The COVID-19-SES’ validity (content, criterion, and construct), reliability (internal consistency and test-retest reliability), and legibility were studied. The COVID-19-SES’ reliability was high (Cronbach’s alpha = 0.906; intraclass correlation coefficient = 0.754). The COVID-19-SES showed good content validity (scale’s content validity index = 0.92) and good criterion validity when the participants’ results on the COVID-19-SES were compared to their general self-efficacy (r = 0.38; p 0.001). Construct validity analysis revealed that the COVID-19-SES’ three-factor structure explained 52.12% of the variance found and it was congruent with the World Health Organisation’s recommendations to prevent COVID-19 contagion and spread. Legibility analysis showed that the COVID-19-SES is easy to read and understand by laypeople. The COVID-19-SES is a psychometrically robust instrument that allows for a valid and reliable assessment of people’s self-efficacy in preventing, detecting symptoms, and home-managing COVID-19

Tomato fruit carotenoid biosynthesis is adjusted to actual ripening progression by a light-dependent mechanism

Carotenoids are isoprenoid compounds that are essential for plants to protect the photosynthetic apparatus against excess light. They also function as health-promoting natural pigments that provide colors to ripe fruit, promoting seed dispersal by animals. Work in Arabidopsis thaliana unveiled that transcription factors of the phytochrome-interacting factor (PIF) family regulate carotenoid gene expression in response to environmental signals (i.e. light and temperature), including those created when sunlight reflects from or passes though nearby vegetation or canopy (referred to as shade). Here we show that PIFs use a virtually identical mechanism to modulate carotenoid biosynthesis during fruit ripening in tomato (Solanum lycopersicum). However, instead of integrating environmental information, PIF-mediated signaling pathways appear to fulfill a completely new function in the fruit. As tomatoes ripen, they turn from green to red due to chlorophyll breakdown and carotenoid accumulation. When sunlight passes through the flesh of green fruit, a self-shading effect within the tissue maintains high levels of PIFs that directly repress the master gene of the fruit carotenoid pathway, preventing undue production of carotenoids. This effect is attenuated as chlorophyll degrades, causing degradation of PIF proteins and boosting carotenoid biosynthesis as ripening progresses. Thus, shade signaling components may have been co-opted in tomato fruit to provide information on the actual stage of ripening (based on the pigment profile of the fruit at each moment) and thus finely coordinate fruit color change. We show how this mechanism may be manipulated to obtain carotenoid-enriched fruits.Peer ReviewedPostprint (published version

Desalination brine effects beyond excess salinity: Unravelling specific stress signaling and tolerance responses in the seagrass Posidonia oceanica

Desalination has been proposed as a global strategy for tackling freshwater shortage in the climate change era. However, there is a concern regarding the environmental effects of high salinity brines discharged from desalination plants on benthic communities. In this context, seagrasses such as the Mediterranean endemic and ecologically important Posidonia oceanica have shown high vulnerability to elevated salinities. Most ecotoxicological studies regarding desalination effects are based on salinity increments using artificial sea salts, although it has been postulated that certain additives within the industrial process of desalination may exacerbate a negative impact beyond just the increased salinities of the brine. To assess the potential effect of whole effluent brines on P. oceanica, mesocosm experiments were conducted within 10 days, simulating salinity increment with either artificial sea salts or brines from a desalination plant (at 43 psμ, 6 psμ over the natural 37 psμ). Morphometrical (growth and necrosis), photochemical (PSII chlorophyll a fluorometry), metabolic, such as hydrogen peroxide (H2O2), thiobarbituric reactive substances (TBARS) and ascorbate/dehydroascorbate (ASC/DHA), and molecular (expression of key tolerance genes) responses were analyzed in each different treatment. Although with a still positive leaf growth, associated parameters decreased similarly for both artificial sea salt and brine treatments. Photochemical parameters did not show general patterns, although only P. oceanica under brines demonstrated greater energy release through heat (NPQ). Lipid peroxidation and upregulation of genes related to oxidative stress (GR, MnSOD, and FeSOD) or ion exclusion (SOS3 and AKT2/3) were similarly incremented on both hypersalinity treatments. Conversely, the ASC/DHA ratio was significantly lower, and the expression of SOS1, CAT, and STRK1 was increased under brine influence. This study revealed that although metabolic and photochemical differences occurred under both hypersalinity treatments, growth (the last sign of physiological detriment) was similarly compromised, suggesting that the potential effects of desalination are mainly caused by brine-associated salinities and are not particularly related to other industrial additives.This investigation was funded by Marie Skłodowska-Curie Action (888415) granted to C.A. Sáez. F. Blanco-Murillo was supported by a grant from Universidad de Alicante (Grant ID: FPUUA98). F. Rodríguez-Rojas was financed by the ANID project FONDECYT 11220425. C.A. Sáez was also financed by project ANID InES I+D 2021 (INID210013)