PD1 blockade improves survival and CD8+ cytotoxic capacity, without increasing inflammation, during normal microbial experience in old mice.

By 2030, individuals 65 years of age or older will make up approximately 20% of the world's population1. Older individuals are at the highest risk for mortality from infections, largely due to the pro-inflammatory, dysfunctional immune response, which is collectively known as immunosenescence2. During aging, CD8+ T cells acquire an exhausted phenotype, including increased expression of inhibitory receptors, such as programmed cell death 1 (PD1), a decline in effector function and elevated expression of inflammatory factors3-7. PD1 reduces T cell receptor activity via SHP2-dependent dephosphorylation of multiple pathways; accordingly, inhibiting PD1 activity through monoclonal antibodies increases CD8+ T cell effector response in young mice8-11. Attempts to improve CD8+ T cell responses by blocking inhibitory receptors are attractive; however, they can lead to adverse immune events due to overamplification of T cell receptor signaling and T cell activation12,13. Here we investigated the effect of monoclonal anti-PD1 immunotherapy during normal microbial experience, otherwise known as exposure to dirty mice, to determine whether it either improves exhausted CD8+ T cell responses in old mice or leads to a heightened inflammatory response and increased mortality.

Structural and transcriptional characterization of pyruvate decarboxylase (PDC) gene family during strawberry fruit ripening process.

Strawberry is one of the most popular fruits in the world, because their high fruit quality, especially with respect to the combination of aroma, flavor, color, and nutritional compounds. Pyruvate decarboxylase (PDC) is the first of two enzymes specifically required for ethanolic fermentation and catalyzes the decarboxylation of pyruvate to yield acetaldehyde and CO2. The ethanol, an important alcohol which acts as a precursor for the ester and other alcohols formation in strawberry, is produced by the PDC. The objective was found all different PDCs genes present in the strawberry genome and investigate PDC gene expression and ligand-protein interactions in strawberry fruit. Volatile organic compounds were evaluated during the development of the fruit. After this, eight FaPDC were identified with four genes that increase the relative expression during fruit ripening process. Molecular dynamics simulations were performed to analyze the behavior of Pyr and TPP ligands within the catalytic and regulatory sites of the PDC proteins. Results indicated that energy-restrained simulations exhibited minor fluctuations in ligand-protein interactions, while unrestrained simulations revealed crucial insights into ligand affinity. TPP consistently displayed strong interactions with the catalytic site, emphasizing its pivotal role in enzymatic activity. However, FaPDC6 and FaPDC9 exhibited decreased pyruvate affinity initially, suggesting unique binding characteristics requiring further investigation. Finally, the present study contributes significantly to understanding PDC gene expression and the intricate molecular dynamics underlying strawberry fruit ripening, shedding light on potential targets for further research in this critical biological pathway.

A giant cause of recurrent fever

A 73-year-old male patient presented to the Emergency Department with history of weight loss, dysphagia, and recurrent fever. The initial chest radiograph showed a mediastinal hypotransparency and to the complaints of dysphagia the patient did a barium swallow test that revealed a giant Zenker diverticulum. Apart from mildly elevated inflammatory markers and despite the extensive investigation of recurrent fever, no other relevant features were found either in blood analysis, microbiological cultures or computerized tomography. He was submitted to surgical intervention, with no recurrence of fever afterwards. It was assumed that food debris and possible microaspirations were responsible for the recurrence of fever and elevation of inflammatory markers. The patient eventually died due to late complications of surgery. Although recurrent fever is frequently linked to systemic disease, the presence of such a giant diverticulum was probably causing an inflammatory response that is usually not seen in these conditions. (AU)

Cirrhosis is associated with lower serological responses to COVID-19 vaccines in patients with chronic liver disease.

Background & Aims: The response of patients with chronic liver disease (CLD) to COVID-19 vaccines remains unclear. Our aim was to assess the humoral immune response and efficacy of two-dose COVID-19 vaccines among patients with CLD of different aetiologies and disease stages. Methods: A total of 357 patients were recruited in clinical centres from six European countries, and 132 healthy volunteers served as controls. Serum IgG (nM), IgM (nM), and neutralising antibodies (%) against the Wuhan-Hu-1, B.1.617, and B.1.1.529 SARS-CoV-2 spike proteins were determined before vaccination (T0) and 14 days (T2) and 6 months (T3) after the second-dose vaccination. Patients fulfilling inclusion criteria at T2 (n = 212) were stratified into 'low' or 'high' responders according to IgG levels. Infection rates and severity were collected throughout the study. Results: Wuhan-Hu-1 IgG, IgM, and neutralisation levels significantly increased from T0 to T2 in patients vaccinated with BNT162b2 (70.3%), mRNA-1273 (18.9%), or ChAdOx1 (10.8%). In multivariate analysis, age, cirrhosis, and type of vaccine (ChAdOx1 > BNT162b2 > mRNA-1273) predicted 'low' humoral response, whereas viral hepatitis and antiviral therapy predicted 'high' humoral response. Compared with Wuhan-Hu-1, B.1.617 and, further, B.1.1.529 IgG levels were significantly lower at both T2 and T3. Compared with healthy individuals, patients with CLD presented with lower B.1.1.529 IgGs at T2 with no additional key differences. No major clinical or immune IgG parameters associated with SARS-CoV-2 infection rates or vaccine efficacy. Conclusions: Patients with CLD and cirrhosis exhibit lower immune responses to COVID-19 vaccination, irrespective of disease aetiology. The type of vaccine leads to different antibody responses that appear not to associate with distinct efficacy, although this needs validation in larger cohorts with a more balanced representation of all vaccines. Impact and Implications: In patients with CLD vaccinated with two-dose vaccines, age, cirrhosis, and type of vaccine (Vaxzevria > Pfizer BioNTech > Moderna) predict a 'lower' humoral response, whereas viral hepatitis aetiology and prior antiviral therapy predict a 'higher' humoral response. This differential response appears not to associate with SARS-CoV-2 infection incidence or vaccine efficacy. However, compared with Wuhan-Hu-1, humoral immunity was lower for the Delta and Omicron variants, and all decreased after 6 months. As such, patients with CLD, particularly those older and with cirrhosis, should be prioritised for receiving booster doses and/or recently approved adapted vaccines.

The Serious Impact of Comorbidities on Methemoglobinemia: A Case Report.

Methemoglobinemia is a rare, life-threatening condition that occurs when the body is exposed to oxidative stress. We present the case of a 72-year-old female with a past medical history of hypertension, obesity, dyslipidemia, and heart failure who was admitted to the emergency department with altered mental status and respiratory failure. After admission, we also identified an atrioventricular block 2:1, anemia, and skin discoloration. We performed endotracheal intubation and started mechanical ventilation due to respiratory failure; however, the patient retained an oxygen "saturation gap" despite adequate ventilation. In the initial laboratory evaluation, methemoglobinemia was found to be 13%, reaching a maximum level of 16%. An electroencephalogram revealed status epilepticus after her admission to the intensive care unit. Despite all efforts and supportive care, methylene blue therapy was never attempted, and the patient died. Our case emphasizes the importance of a high index of suspicion for methemoglobinemia, especially in the presence of an oxygen "saturation gap," and that despite relatively low levels of methemoglobinemia, it can have a more severe clinical presentation in patients with comorbidities. In these patients, a reduced threshold for administering methylene blue should be taken into account.

A giant cause of recurrent fever.

A 73-year-old male patient presented to the Emergency Department with history of weight loss, dysphagia, and recurrent fever. The initial chest radiograph showed a mediastinal hypotransparency and to the complaints of dysphagia the patient did a barium swallow test that revealed a giant Zenker diverticulum. Apart from mildly elevated inflammatory markers and despite the extensive investigation of recurrent fever, no other relevant features were found either in blood analysis, microbiological cultures or computerized tomography. He was submitted to surgical intervention, with no recurrence of fever afterwards. It was assumed that food debris and possible microaspirations were responsible for the recurrence of fever and elevation of inflammatory markers. The patient eventually died due to late complications of surgery. Although recurrent fever is frequently linked to systemic disease, the presence of such a giant diverticulum was probably causing an inflammatory response that is usually not seen in these conditions.

Epigenetics, DNA damage, and aging.

Over the course of a human lifespan, genome integrity erodes, leading to an increased abundance of several types of chromatin changes. The abundance of DNA lesions (chemical perturbations to nucleotides) increases with age, as does the number of genomic mutations and transcriptional disruptions caused by replication or transcription of those lesions, respectively. At the epigenetic level, precise DNA methylation patterns degrade, likely causing increasingly stochastic variations in gene expression. Similarly, the tight regulation of histone modifications begins to unravel. The genomic instability caused by these mechanisms allows transposon element reactivation and remobilization, further mutations, gene dysregulation, and cytoplasmic chromatin fragments. This cumulative genomic instability promotes cell signaling events that drive cell fate decisions and extracellular communications known to disrupt tissue homeostasis and regeneration. In this Review, we focus on age-related epigenetic changes and their interactions with age-related genomic changes that instigate these events.

[Pharmacokinetic study of mycophenolic acid in pediatric kidney transplantation]. / Estudio farmacocinético del ácido micofenólico en el trasplante renal pediátrico.

INTRODUCTION: Mycophenolic acid (MPA) is among the drugs used to achieve effective immunosuppression in kid ney transplantation (KT), which is characterized by complex pharmacokinetics and high intra- and interindividual variability. Monitoring the trough concentration level (C0) of MPA for dosage ad justments is considered controversial, mainly due to its low correlation with the area under the curve (AUC). OBJECTIVE: To correlate the C0 and AUC of MPA in pediatric patients with KT. PATIENTS AND METHOD: Prospective study carried out in 54 KT patients under treatment with MPA. Linear regressions and correlations were performed between ABC and C0. Multiple comparisons group analysis was performed according to post-transplant time and the two oral presentations of MPA. RESULTS: The plasma level that best correlates with AUC was C0 (r2 = 0.52). There was a significant group of patients with subtherapeutic levels (36.6% of all measurements). It was also determined that the C0 must be between 1.42 and 4.55 µg/ml for the AUC to be within the therapeutic range. It was shown that the correlation between C0 and AUC improves after three months post-transplantation and is even better when administering mycophenolate mofetil. CONCLUSION: The use of C0 is recom mended to adjust the dose of MPA in pediatric patients with KT, especially in those with more than 3 months post-transplantation. For patients with early KT or complex clinical pictures, monitoring using ABC is recommended.

Metabolic changes in cucumber leaves are enhanced by blue light but differentially affected by UV interactions with light signalling pathways in the visible spectrum.

Ultraviolet radiation (UV, 280-400 nm) as an environmental signal triggers metabolic acclimatory responses. However, how different light qualities affect UV acclimation during growth is poorly understood. Here, cucumber plants (Cucumis sativus) were grown under blue, green, red, or white light in combination with UV. Their effects on leaf metabolites were determined using untargeted metabolomics. Blue and white growth light triggered increased levels of compounds related to primary and secondary metabolism, including amino acids, phenolics, hormones, and compounds related to sugar metabolism and the TCA cycle. In contrast, supplementary UV in a blue or white light background decreased leaf content of amino acids, phenolics, sugars, and TCA-related compounds, without affecting abscisic acid, auxin, zeatin, or jasmonic acid levels. However, in plants grown under green light, UV induced increased levels of phenolics, hormones (auxin, zeatin, dihydrozeatin-7-N-dihydrozeatin, jasmonic acid), amino acids, sugars, and TCA cycle-related compounds. Plants grown under red light with UV mainly showed decreased sugar content. These findings highlight the importance of the blue light component for metabolite accumulation. Also, data on interactions of UV with green light on the one hand, and blue or white light on the other, further contributes to our understanding of light quality regulation of plant metabolism.

Elevated CO2 Improves the Physiology but Not the Final Yield in Spring Wheat Genotypes Subjected to Heat and Drought Stress During Anthesis.

Heat and drought events often occur concurrently as a consequence of climate change and have a severe impact on crop growth and yield. Besides, the accumulative increase in the atmospheric CO2 level is expected to be doubled by the end of this century. It is essential to understand the consequences of climate change combined with the CO2 levels on relevant crops such as wheat. This study evaluated the physiology and metabolite changes and grain yield in heat-sensitive (SF29) and heat-tolerant (LM20) wheat genotypes under individual heat stress or combined with drought applied during anthesis at ambient (aCO2) and elevated CO2 (eCO2) levels. Both genotypes enhanced similarly the WUE under combined stresses at eCO2. However, this increase was due to different stress responses, whereas eCO2 improved the tolerance in heat-sensitive SF29 by enhancing the gas exchange parameters, and the accumulation of compatible solutes included glucose, fructose, ß-alanine, and GABA to keep water balance; the heat-tolerant LM20 improved the accumulation of phosphate and sulfate and reduced the lysine metabolism and other metabolites including N-acetylornithine. These changes did not help the plants to improve the final yield under combined stresses at eCO2. Under non-stress conditions, eCO2 improved the yield of both genotypes. However, the response differed among genotypes, most probably as a consequence of the eCO2-induced changes in glucose and fructose at anthesis. Whereas the less-productive genotype LM20 reduced the glucose and fructose and increased the grain dimension as the effect of the eCO2 application, the most productive genotype SF29 increased the two carbohydrate contents and ended with higher weight in the spikes. Altogether, these findings showed that the eCO2 improves the tolerance to combined heat and drought stress but not the yield in spring wheat under stress conditions through different mechanisms. However, under non-stress conditions, it could improve mainly the yield to the less-productive genotypes. Altogether, the results demonstrated that more studies focused on the combination of abiotic stress are needed to understand better the spring wheat responses that help the identification of genotypes more resilient and productive under these conditions for future climate conditions.

Effects of UV radiation on transcript and metabolite accumulation are dependent on monochromatic light background in cucumber.

During recent years, we have advanced our understanding of plant molecular responses to ultraviolet radiation (UV, 280-400 nm); however, how plants respond to UV radiation under different spectral light qualities is poorly understood. In this study, cucumber plants (Cucumis sativus "Lausanna RZ F1") were grown under monochromatic blue, green, red, and broadband white light in combination with UV radiation. The effects of light quality and UV radiation on acclimatory responses were assessed by measuring transcript accumulation of ELONGATED HYPOCOTYL 5 (HY5), CHALCONE SYNTHASE 2 (CHS2), and LIGHT HARVESTING COMPLEX II (LHCII), and the accumulation of flavonoids and hydroxycinnamic acids in the leaves. The growth light backgrounds differentially regulated gene expression and metabolite accumulation. While HY5 and CHS2 transcripts were induced by blue and white light, LHCII was induced by white and red light. Furthermore, UV radiation antagonized the effects of blue, red, green, and white light on transcript accumulation in a gene-dependent manner. Plants grown under blue light with supplementary UV radiation increased phenylalanine, flavonol disaccharide I and caffeic acid contents compared to those exposed only to blue light. UV radiation also induced the accumulation of flavonol disaccharide I and II, ferulic acid hexose and coumaric acid hexose in plants grown under green light. Our findings provide a further understanding of plant responses to UV radiation in combination with different light spectra and contribute to the design of light recipes for horticultural practices that aim to modify plant metabolism and ultimately improve crop quality.

Effect of Exogenous Auxin Treatment on Cell Wall Polymers of Strawberry Fruit.

The role of auxin in the fruit-ripening process during the early developmental stages of commercial strawberry fruits (Fragaria x ananassa) has been previously described, with auxin production occurring in achenes and moving to the receptacle. Additionally, fruit softening is a consequence of the depolymerization and solubilization of cell wall components produced by the action of a group of proteins and enzymes. The aim of this study was to compare the effect of exogenous auxin treatment on the physiological properties of the cell wall-associated polysaccharide contents of strawberry fruits. We combined thermogravimetric (TG) analysis with analyses of the mRNA abundance, enzymatic activity, and physiological characteristics related to the cell wall. The samples did not show a change in fruit firmness at 48 h post-treatment; by contrast, we showed changes in the cell wall stability based on TG and differential thermogravimetric (DTG) analysis curves. Less degradation of the cell wall polymers was observed after auxin treatment at 48 h post-treatment. The results of our study indicate that auxin treatment delays the cell wall disassembly process in strawberries.

Ugni molinae Fruit as a Source of Bioactive Compounds with Good Quality Traits.

Since the intake of fruits and vegetables displays important effects on the incidence of several chronic diseases in humans, consumers' attention worldwide is focused on the identification of functional foods. In this sense, Ugni molinae (murtilla or murta fruit) is an important source of molecules with a strong antioxidant capacity that is widely used as a medicinal plant in Southern Argentina-Chile. Research on murtilla berries showed that this fruit and its leaves can be an excellent source of polyphenols and bioactive compounds with antibacterial and antioxidant capacity. This review is aimed at providing valuable information and discussing the available literature focused on four principal points: (i) fruit quality and plant physiology, (ii) compound content with bioactive properties, (iii) health properties for consumers of the fruit and leaves, and (iv) challenges for future research. Based on these four points, we propose that murtilla fruit can be a potential ingredient for new functional food products.

The effect of individual and combined drought and heat stress under elevated CO2 on physiological responses in spring wheat genotypes.

Abiotic stress due to climate change with continuous rise of atmospheric CO2 concentration is predicted to cause severe changes to crop productivity. Thus, research into wheat cultivars, capable of maintaining yield under limiting conditions is necessary. The aim of this study was to investigate the physiological responses of spring wheat to individual and combined drought- and heat events and their interaction with CO2 concentration. Two heat sensitive (LM19, KU10) and two heat tolerant (LM62, GN5) genotypes were selected and grown under ambient (400 ppm, aCO2) and elevated (800 ppm, eCO2) CO2 concentrations. At the tillering stage, the wheat plants were subjected to different treatments: control, progressive drought, heat and combined drought and heat stress. Our results showed that eCO2 mitigated the negative impact of the moderate stress in all genotypes. However, no distinctive responses were observed in some of the measured parameters between heat sensitive and tolerant genotypes. All genotypes grown at eCO2 had significantly higher net photosynthetic rates and maintained maximum quantum efficiency of PSII photochemistry under heat and combined stress compared to aCO2. Under heat and combined stress, the chlorophyll a:b ratios decreased only in heat tolerant genotypes at eCO2 compared to the control. Furthermore, the heat tolerant genotypes grown at eCO2 showed an increased glucose and fructose contents and a decreased sucrose content under combined stress compared to aCO2. These findings provide new insights into the underlying mechanisms of different genotypic responses to combined abiotic stresses at eCO2 that differ from the response to individual stresses.

DNA damage-how and why we age?

Aging is a complex process that results in loss of the ability to reattain homeostasis following stress, leading, thereby, to increased risk of morbidity and mortality. Many factors contribute to aging, such as the time-dependent accumulation of macromolecular damage, including DNA damage. The integrity of the nuclear genome is essential for cellular, tissue, and organismal health. DNA damage is a constant threat because nucleic acids are chemically unstable under physiological conditions and vulnerable to attack by endogenous and environmental factors. To combat this, all organisms possess highly conserved mechanisms to detect and repair DNA damage. Persistent DNA damage (genotoxic stress) triggers signaling cascades that drive cells into apoptosis or senescence to avoid replicating a damaged genome. The drawback is that these cancer avoidance mechanisms promote aging. Here, we review evidence that DNA damage plays a causal role in aging. We also provide evidence that genotoxic stress is linked to other cellular processes implicated as drivers of aging, including mitochondrial and metabolic dysfunction, altered proteostasis and inflammation. These links between damage to the genetic code and other pillars of aging support the notion that DNA damage could be the root of aging.

A review of organic waste enrichment for inducing palatability of black soldier fly larvae: Wastes to valuable resources.

The increase of annual organic wastes generated worldwide has become a major problem for many countries since the mismanagement could bring about negative effects on the environment besides, being costly for an innocuous disposal. Recently, insect larvae have been investigated to valorize organic wastes. This entomoremediation approach is rising from the ability of the insect larvae to convert organic wastes into its biomass via assimilation process as catapulted by the natural demand to complete its lifecycle. Among the insect species, black soldier fly or Hermetia illucens is widely researched since the larvae can grow in various environments while being saprophagous in nature. Even though black soldier fly larvae (BSFL) can ingest various decay materials, some organic wastes such as sewage sludge or lignocellulosic wastes such as waste coconut endosperm are destitute of decent nutrients that could retard the BSFL growth. Hence, blending with nutrient-rich low-cost substrates such as palm kernel expeller, soybean curd residue, etc. is employed to fortify the nutritional contents of larval feeding substrates prior to administering to the BSFL. Alternatively, microbial fermentation can be adopted to breakdown the lignocellulosic wastes, exuding essential nutrients for growing BSFL. Upon reaching maturity, the BSFL can be harvested to serve as the protein and lipid feedstock. The larval protein can be made into insect meal for farmed animals, whilst the lipid source could be extracted and transesterified into larval biodiesel to cushion the global energy demands. Henceforth, this review presents the influence of various organic wastes introduced to feed BSFL, targeting to reduce wastes and producing biochemicals from mature larvae through entomoremediation. Modification of recalcitrant organic wastes via fermentation processes is also unveiled to ameliorate the BSFL growth. Lastly, the sustainable applications of harvested BSFL biomass are as well covered together with the immediate shortcomings that entail further researches.

Molecular and structural insights into FaEXPA5, an alpha-expansin protein related with cell wall disassembly during ripening of strawberry fruit.

Cell wall modification is one of the main factors that produce the tissue softening during ripening of many fruit including strawberry (Fragaria x ananassa). Expansins have been studied for over 20 years as a class of the important cell growth regulators, and in the last years these have been related with the fruit softening. In strawberry, five partial sequences of the expansins genes were described in the past, this analysis showed that FaEXP5 partial gene was present throughout fruit development, but was more strongly expressed during ripening. Now, we reported the full length of this α-expansin (FaEXPA5), whose had been related with fruit softening, and the protein structural was described by homology model. Their transcript accumulation during softening was confirmed by qRT-PCR, displaying a high accumulation rate during fruit ripening. In silico analysis of promoter sequence showed four ABA and two auxin cis-regulatory elements, potentially responsible for the expression patterns observed in response to the hormone treatments. Additionally, 3D protein model displayed two domains and one open groove characteristic of expansin structures. The protein-ligand interactions were evaluated by molecular dynamic (MD) simulation using three different long structure ligands (a cellulose fiber, a xyloglucan fiber (XXXG type), and a pectin fiber as control). Favorable interactions were observed with xyloglucan and cellulose, being cellulose the best ligand with lower RMSD value. Additionally, MD simulations showed that FaEXPA5 can interact with the ligands through residues present in the open groove along the two domains.

Basic Family Relations, Parental Bonding, and Dyadic Adjustment in Families with a Member with Psychosis.

The aim of the current study is to describe and explore basic family relations, parental bonding, and dyadic adjustment in families with offspring diagnosed with a psychotic disorder. The sample was made up of 120 participants, 60 in the clinical group (GCL) and 60 in the comparison group (GCP). All participants were assessed using the basic family relations evaluation questionnaire (CERFB), the parental bonding instrument (PBI), and the dyadic adjustment scale (DAS). The results showed differences between the clinical and comparison groups in terms of perceptions of basic family relations, dyadic adjustment and parental bonding. The clinical group recorded less favorable results for all of these variables. More specifically, the study observed significant differences between the groups in parental function, overprotection and caring. This study deepens our understanding of how family assessment and relational diagnoses can serve as prevention and intervention tools for families affected by a psychotic disorder.

Spectral Composition of Light Affects Sensitivity to UV-B and Photoinhibition in Cucumber.

Ultraviolet B (UV-B) (280-315 nm) and ultraviolet A (UV-A) (315-400 nm) radiation comprise small portions of the solar radiation but regulate many aspects of plant development, physiology and metabolism. Until now, how plants respond to UV-B in the presence of different light qualities is poorly understood. This study aimed to assess the effects of a low UV-B dose (0.912 ± 0.074 kJ m-2 day-1, at a 6 h daily UV exposure) in combination with four light treatments (blue, green, red and broadband white at 210 µmol m-2 s-1 Photosynthetically active radiation [PAR]) on morphological and physiological responses of cucumber (Cucumis sativus cv. "Lausanna RZ F1"). We explored the effects of light quality backgrounds on plant morphology, leaf gas exchange, chlorophyll fluorescence, epidermal pigment accumulation, and on acclimation ability to saturating light intensity. Our results showed that supplementary UV-B significantly decreased biomass accumulation in the presence of broad band white, blue and green light, but not under red light. UV-B also reduced the photosynthetic efficiency of CO2 fixation (α) when combined with blue light. These plants, despite showing high accumulation of anthocyanins, were unable to cope with saturating light conditions. No significant effects of UV-B in combination with green light were observed for gas exchange and chlorophyll fluorescence parameters, but supplementary UV-B significantly increased chlorophyll and flavonol contents in the leaf epidermis. Plants grown under red light and UV-B significantly increased maximum photosynthetic rate and dark respiration compared to pure red light. Additionally, red and UV-B treated plants exposed to saturating light intensity showed higher quantum yield of photosystem II (PSII), fraction of open PSII centres and electron transport rate and showed no effect on the apparent maximum quantum efficiency of PSII photochemistry (Fv/Fm) or non-photochemical quenching, in contrast to solely red-light conditions. These findings provide new insights into how plants respond to UV-B radiation in the presence of different light spectra.