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Leaf senescence is a complex process, which has dramatic consequences on crop yield. In sunflower, gap between potential and actual yields reveals the economic impact of senescence. Indeed, sunflower plants are incapable of maintaining their green leaf area over sustained periods. This study characterizes the leaf senescence process in sunflower through a systems biology approach integrating transcriptomic and metabolomic analyses: plants being grown under both glasshouse and field conditions. Our results revealed a correspondence between profile changes detected at the molecular, biochemical and physiological level throughout the progression of leaf senescence measured at different plant developmental stages. Early metabolic changes were detected prior to anthesis and before the onset of the first senescence symptoms, with more pronounced changes observed when physiological and molecular variables were assessed under field conditions. During leaf development, photosynthetic activity and cell growth processes decreased, whereas sucrose, fatty acid, nucleotide and amino acid metabolisms increased. Pathways related to nutrient recycling processes were also up‐regulated. Members of the NAC, AP2‐EREBP, HB, bZIP and MYB transcription factor families showed high expression levels, and their expression level was highly correlated, suggesting their involvement in sunflower senescence. The results of this study thus contribute to the elucidation of the molecular mechanisms involved in the onset and progression of leaf senescence in sunflower leaves as well as to the identification of candidate genes involved in this process.

Airway clearance therapy (ACT) is considered an important approach to improve airway clearance in children with cystic fibrosis (CF). Daily ACT administration requires substantial commitments of time and energy that complicate ACT and reduce its benefits. It is crucial to establish ACT as a positive routine. Music therapy (MT) is an aspect of integrative strategies to ameliorate the psycho-emotional consequences of chronic diseases, and a MT intervention could help children with CF between the ages of 2 and 17 develop a positive response. The aim of this randomized controlled trial was to evaluate the effects of specifically composed and recorded instrumental music as an adjunct to ACT. We compared the use of specifically composed music (Treated Group, TG), music that the patient liked (Placebo Group, PG), and no music (Control Group, CG) during the usual ACT routine in children with CF aged from 2 to 17. The primary outcomes, i.e., enjoyment and perception of time, were evaluated via validated questionnaires. The secondary outcome, i.e., efficiency, was evaluated in terms of avoided healthcare resources. Enjoyment increased after the use of the specifically composed music (children +0.9 units/parents +1.7 units; p<0.05) compared to enjoyment with no music (0 units) and familiar music (+0.5 units). Perception of time was 11.1 min (±3.9) less than the actual time in the TG (p<0.05), 3.9 min (±4.2) more than the actual time in the PG and unchanged in the CG. The potential cost saving related to respiratory exacerbations was €6,704.87, while the cost increased to €33,524.35 in the CG and to €13,409.74 in the PG. In conclusion, the specifically composed, played and compiled instrumental recorded music is an effective adjunct to ACT to establish a positive response and is an efficient option in terms of avoided costs. Trial registered as ISRCTN11161411. ISRCTN registry (www.isrctn.com).

Summary Acremonium strictum elicitor subtilisin (AsES) is a 34‐kDa serine‐protease secreted by the strawberry fungal pathogen A. strictum. On AsES perception, a set of defence reactions is induced, both locally and systemically, in a wide variety of plant species and against pathogens of alternative lifestyles. However, it is not clear whether AsES proteolytic activity is required for triggering a defence response or if the protein itself acts as an elicitor. To investigate the necessity of the protease activity to activate the defence response, AsES coding sequences of the wild‐type gene and a mutant on the active site (S226A) were cloned and expressed in Escherichia coli. Our data show that pretreatment of Arabidopsis plants with inactive proteins, i.e. inhibited with phenylmethylsulphonyl fluoride (PMSF) and mutant, resulted in an increased systemic resistance to Botrytis cinerea and expression of defence‐related genes in a temporal manner that mimics the effect already reported for the native AsES protein. The data presented in this study indicate that the defence‐eliciting property exhibited by AsES is not associated with its proteolytic activity. Moreover, the enhanced expression of some immune marker genes, seedling growth inhibition and the involvement of the co‐receptor BAK1 observed in plants treated with AsES suggests that AsES is being recognized as a pathogen‐associated molecular pattern by a leucine‐rich repeat receptor. The understanding of the mechanism of action of AsES will contribute to the development of new breeding strategies to confer durable resistance in plants.

Acquired resistance to MEK1/2 inhibitors (MEKi) arises through amplification of BRAF V600E or KRAS G13D to reinstate ERK1/2 signalling. Here we show that BRAF V600E amplification and MEKi resistance are reversible following drug withdrawal. Cells with BRAF V600E amplification are addicted to MEKi to maintain a precise level of ERK1/2 signalling that is optimal for cell proliferation and survival, and tumour growth in vivo. Robust ERK1/2 activation following MEKi withdrawal drives a p57 KIP2 -dependent G1 cell cycle arrest and senescence or expression of NOXA and cell death, selecting against those cells with amplified BRAF V600E . p57 KIP2 expression is required for loss of BRAF V600E amplification and reversal of MEKi resistance. Thus, BRAF V600E amplification confers a selective disadvantage during drug withdrawal, validating intermittent dosing to forestall resistance. In contrast, resistance driven by KRAS G13D amplification is not reversible; rather ERK1/2 hyperactivation drives ZEB1-dependent epithelial-to-mesenchymal transition and chemoresistance, arguing strongly against the use of drug holidays in cases of KRAS G13D amplification. Colorectal cancer cells can acquire resistance to MEK inhibition due to BRAF or KRAS amplification. Here, the authors show that while MEK inhibitor withdrawal in BRAF mutant cells restores sensitivity to the inhibitor through the loss of BRAF amplification mediated by a p57-dependent mechanism, drug withdrawal from KRAS mutant cells does not restore sensitivity but results in EMT and chemoresistance.

Hao-Fountain syndrome (HAFOUS) is a rare autosomal dominant neurodevelopmental disorder caused by pathogenic variants. A diagnostic blood DNA methylation episignature has been established, yet the broader regulatory consequences of haploinsufficiency and their tissue specificity remain incompletely characterized. We performed genome-wide DNA methylation profiling, RNA sequencing, and cis expression quantitative trait methylation (eQTM) analysis in whole blood (n = 9) and patient-derived skin fibroblasts (n = 4). Differential methylation was assessed and methylation-expression coupling within ±250 kb of each DMR. DMRs were further interpreted using BCOR, H2AK119ub1, and H3K27me3 ChIP-Rx datasets from neural models. Blood reproduced the established hypermethylation episignature and yielded 17 significant DMRs, accompanied by modest numbers of differentially expressed genes and eQTMs. Fibroblasts displayed internally coherent regulatory patterns, including 2,143 nominal DMRs, 310 differentially expressed genes, and 559 significant eQTMs. Convergent methylation-expression changes prominently involved the HOXB cluster (HOXB3, HOXB5, HOXB6). Both blood- and fibroblast-derived DMRs showed significant enrichment for BCOR- and H2AK119ub1-marked regions, consistent with disruption of non-canonical PRC1.1-associated chromatin. Cross-tissue comparison revealed limited overlap, supporting marked tissue specificity in methylation-expression relationships. haploinsufficiency is associated with a restricted set of regulatory loci enriched within PRC1-associated chromatin domains. Fibroblasts revealed coherent methylation and expression changes at developmental genes, whereas blood captured the diagnostic episignature and a smaller set of downstream regulatory alterations. Together, this dual-tissue integrative analysis refines the molecular consequences of reduced dosage and provides a framework for future mechanistic studies in disease-relevant cellular models.

Abstract Background Chronic bronchopulmonary infection due to MRSA in people with cystic fibrosis (pwCF) has been associated with accelerated decline in lung function, increased hospitalizations and increased mortality. Material and methods We studied microbiological and genomic characteristics of MRSA isolates recovered from pwCF in two Spanish multicentre studies (2013, 2021). Antimicrobial susceptibility was performed. WGS was carried out to determine population structure [MLST, spa-typing, staphylococcal cassette chromosome mec (SCCmec)], resistome and virulome. Clinical charts of MRSA-infected and MRSA-non-infected pwCF were also reviewed. Results MRSA infection prevalence decreased between 2013 (29/341, 8.5%) and 2021 (21/326, 6.4%) (P = 0.378). Differences in lung function were observed between infected and non-infected patients (P < 0.005). A higher prevalence of hospital-acquired (HA) clones was found compared with community-acquired (CA) clones (2013: 67% versus 33%; and 2021: 71% versus 29%). Overall, we noted clustering of isolates based on year of sampling, type of acquisition and clonal complex (CC). HA-MRSA population was dominated by CC5, with ST125-MRSA-IVc-t067 the most prevalent lineage (37%). A higher clonal diversity was detected among CA-MRSA. One Panton–Valentine leucocidin (PVL)-positive strain (ST8-MRSA-IV) and three strains of porcine origin (two ST398-MRSA-V-t011, one ST398-MRSA-V-t8567) were found. Additionally, acquired resistance genes (n = 24) were detected, including the cfr gene conferring linezolid resistance. A higher gentamicin resistance was found in 2021 (42%) compared with 2013 (7%) (P = 0.046), associated with the aac(6′)-aph(2″) gene. Conclusions Despite a decrease in MRSA prevalence, we showed its potential impact on CF severity and progression. Moreover, we observed great genotypic and phenotypic diversity in MRSA isolates from pwCF as well as an MDR trait.

Previous studies have shown that caloric restriction decreases mitochondrial oxygen radical production and oxidative DNA damage in rat organs, which can be linked to the slowing of aging rate induced by this regime. These two characteristics are also typical of long-lived animals. However, it has never been investigated if those decreases are linked to the decrease in the intake of calories themselves or to decreases in specific dietary components. In this study the possible role of the dietary protein was investigated. Using semipurified diets, the ingestion of proteins of Wistar rats was decreased by 40% below that of controls while the other dietary components were ingested at the same level as in animals fed ad libitum. After seven weeks in this regime the liver of the protein restricted animals showed 30-40% decreases in mitochondrial production of reactive oxygen species (ROS) and in oxidative damage to nuclear and mitochondrial DNA. The decreases in ROS generation occurred specifically at complex I. They also occurred without changes in mitochondrial oxygen consumption. Instead, there was a decrease in the percent free radical leak (the percentage of total electron flow leading to ROS generation in the respiratory chain). These results are strikingly similar to those previously obtained after 40% caloric restriction in the liver of Wistar rats. Thus, the results suggest that part of the decrease in aging rate induced by caloric restriction can be due to the decreased intake of proteins acting through decreases in mitochondrial ROS production and oxidative DNA damage. Interestingly, these tissue oxidative stress-linked parameters can be lowered by restricting only the intake of dietary protein, probably a more feasible option than caloric restriction for adult humans.

Previous studies in mammalian models indicate that the rate of mitochondrial reactive oxygen species ROS production and the ensuing modification of mitochondrial DNA (mtDNA) link oxidative stress to aging rate. However, there is scarce information concerning this in relation to caloric restriction (CR) in the brain, an organ of maximum relevance for ageing. Furthermore, it has never been studied if CR started late in life can improve those oxidative stress-related parameters. In this investigation, rats were subjected during 1 year to 40% CR starting at 24 months of age. This protocol of CR significantly decreased the rate of mitochondrial H(2)O(2) production (by 24%) and oxidative damage to mtDNA (by 23%) in the brain below the level of both old and young ad libitum-fed animals. In agreement with the progressive character of aging, the rate of H(2)O(2) production of brain mitochondria stayed constant with age. Oxidative damage to nuclear DNA increased with age and this increase was fully reversed by CR to the level of the young controls. The decrease in ROS production induced by CR was localized at Complex I and occurred without changes in oxygen consumption. Instead, the efficiency of brain mitochondria to avoid electron leak to oxygen at Complex I was increased by CR. The mechanism involved in that increase in efficiency was related to the degree of electronic reduction of the Complex I generator. The results agree with the idea that CR decreases aging rate in part by lowering the rate of free radical generation of mitochondria in the brain.

Dietary restriction (DR) lowers mitochondrial reactive oxygen species (ROS) generation and oxidative damage and increases maximum longevity in rodents. Protein restriction (PR) or methionine restriction (MetR), but not lipid or carbohydrate restriction, also cause those kinds of changes. However, previous experiments of MetR were performed only at 80% MetR, and substituting dietary methionine with glutamate in the diet. In order to clarify if MetR can be responsible for the lowered ROS production and oxidative stress induced by standard (40%) DR, Wistar rats were subjected to 40% or 80% MetR without changing other dietary components. It was found that both 40% and 80% MetR decrease mitochondrial ROS generation and percent free radical leak in rat liver mitochondria, similarly to what has been previously observed in 40% PR and 40% DR. The concentration of complexes I and III, apoptosis inducing factor, oxidative damage to mitochondrial DNA, five different markers of protein oxidation, glycoxidation or lipoxidation and fatty acid unsaturation were also lowered. The results show that 40% isocaloric MetR is enough to decrease ROS production and oxidative stress in rat liver. This suggests that the lowered intake of methionine is responsible for the decrease in oxidative stress observed in DR.

Methionine restriction without energy restriction increases, like caloric restriction, maximum longevity in rodents. Previous studies have shown that methionine restriction strongly decreases mitochondrial reactive oxygen species (ROS) production and oxidative damage to mitochondrial DNA, lowers membrane unsaturation, and decreases five different markers of protein oxidation in rat heart and liver mitochondria. It is unknown whether methionine supplementation in the diet can induce opposite changes, which is also interesting because excessive dietary methionine is hepatotoxic and induces cardiovascular alterations. Because the detailed mechanisms of methionine-related hepatotoxicity and cardiovascular toxicity are poorly understood and today many Western human populations consume levels of dietary protein (and thus, methionine) 2-3.3 fold higher than the average adult requirement, in the present experiment we analyze the effect of a methionine supplemented diet on mitochondrial ROS production and oxidative damage in the rat liver and heart mitochondria. In this investigation male Wistar rats were fed either a L-methionine-supplemented (2.5 g/100 g) diet without changing any other dietary components or a control (0.86 g/100 g) diet for 7 weeks. It was found that methionine supplementation increased mitochondrial ROS generation and percent free radical leak in rat liver mitochondria but not in rat heart. In agreement with these data oxidative damage to mitochondrial DNA increased only in rat liver, but no changes were observed in five different markers of protein oxidation in both organs. The content of mitochondrial respiratory chain complexes and AIF (apoptosis inducing factor) did not change after the dietary supplementation while fatty acid unsaturation decreased. Methionine, S-AdenosylMethionine and S-AdenosylHomocysteine concentration increased in both organs in the supplemented group. These results show that methionine supplementation in the diet specifically increases mitochondrial ROS production and mitochondrial DNA oxidative damage in rat liver mitochondria offering a plausible mechanism for its hepatotoxicity.