Artículos (Bioquímica Vegetal y Biología Molecular)
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Artículo Properties of polyplexes formed between a cationic polymer derived from l-arabinitol and nucleic acids(Royal Society of Chemistry, 2021-05-14) Pérez Alfonso, David; López López, Manuel; López-Cornejo, María del Pilar; Romero Azogil, Lucía; Benito Hernández, Elena María; García Martín, María de Gracia; García Calderón, Clara Beatriz; Valle Rosado, Iván; Romero Balestra, Fernando; Huertas Sánchez, Pablo; García Calderón, Margarita; Moyá Morán, María Luisa; Universidad de Sevilla. Departamento de Química Física; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Universidad de Sevilla. Departamento de Química Orgánica y Farmacéutica; Universidad de Sevilla. Departamento de Genética; Junta de Andalucía; Universidad de Sevilla; Ministerio de Ciencia, Innovación y Universidades (MICINN). España; European Union (UE)In this work a sugar-based cationic polymer derived from L-arabinitol, PUArab, was prepared and its interactions with the linear calf thymus DNA and with the circular plasmid pEGFP-C1 were investigated at different N/P ratios. The polyplexes were characterized by using several techniques. For both nucleic acids, a charge inversion was observed, together with a conformational change from a coiled structure to a more compacted one. However, the N/P ratio required to observe the DNA condensation depended on the nucleic acid architecture. PUArab presents low toxicity in several cell lines. The transfection efficiency, TE, of the PUArab/pEGFP-C1 polyplexes was investigated at several N/P ratios in order to study their potential as vectors in gene transfection.Artículo Phosphorylation of cytochrome c at tyrosine 48 finely regulates its binding to the histone chaperone SET/TAF-Iβ in the nucleus(Wiley, 2024-11-16) Tamargo Azpilicueta, Joaquín; Casado Combreras, Miguel Ángel; Giner Arroyo, Rafael Luis; Velázquez Campoy, Adrián; Márquez Escudero, Inmaculada; Olloqui Sariego, José Luis; Rosa Acosta, Miguel Ángel de la; Díaz Moreno, Irene; Universidad de Sevilla. Departamento de Química Física; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia, Innovación y Universidades (MICINN). España; European Union (UE); Junta de AndalucíaPost-translational modifications (PTMs) of proteins are ubiquitous processes present in all life kingdoms, involved in the regulation of protein stability, subcellular location and activity. In this context, cytochrome c (Cc) is an excellent case study to analyze the structural and functional changes induced by PTMS as Cc is a small, moonlighting protein playing different roles in different cell compartments at different cell-cycle stages. Cc is actually a key component of the mitochondrial electron transport chain (ETC) under homeostatic conditions but is translocated to the cytoplasm and even the nucleus under apoptotic conditions and/or DNA damage. Phosphorylation does specifically alter the Cc redox activity in the mitochondria and the Cc non-redox interaction with apoptosis-related targets in the cytoplasm. However, little is known on how phosphorylation alters the interaction of Cc with histone chaperones in the nucleus. Here, we report the effect of Cc Tyr48 phosphorylation by examining the protein interaction with SET/TAF-Iβ in the nuclear compartment using a combination of molecular dynamics simulations, biophysical and structural approaches such as isothermal titration calorimetry (ITC) and nuclear magnetic resonance (NMR) and in cell proximity ligation assays. From these experiments, we infer that Tyr48 phosphorylation allows a fine-tuning of the Cc-mediated inhibition of SET/TAF-Iβ histone chaperone activity in vitro. Our findings likewise reveal that phosphorylation impacts the nuclear, stress-responsive functions of Cc, and provide an experimental framework to explore novel aspects of Cc post-translational regulation in the nucleus.Artículo Use of a Biostimulant Obtained from Slaughterhouse Sludge in a Greenhouse Tomato Crop(MDPI, 2022) Ávila Pozo, Paloma; Parrado Rubio, Juan; Caballero Jiménez, Pablo; Tejada Moral, Manuel; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Universidad de Sevilla. Departamento de Cristalografía, Mineralogía y Química Agrícola; Junta de Andalucía; European Union (UE). H2020; Ministerio de Ciencia, Innovación y Universidades (MICINN). EspañaCurrently, the use of biostimulants is widespread in sustainable agriculture because they represent an alternative to chemical fertilizers. In this manuscript, we investigate the response of a greenhouse tomato crop grown in pots to a biostimulant obtained from slaughterhouse sludge applied continuously to the substrate under which the tomato crop was grown or applied directly via the foliar route. Two doses of biostimulant (0.7 and 1.4 g L−1), applied four times throughout the crop growth period (120 days), were used. During this period, the height of the plants, number of flowers and number of fruits obtained were measured. After 90 days of the growth period, the nutrient contents in leaves as well as the chlorophyll a and b contents were analyzed. For fruits, nutrient and lycopene contents were determined, and the equatorial diameter and average fresh and dry weight were measured. The results indicate a higher content of nutrients and chlorophyll a and b in the leaves of plants treated with the highest dose of biostimulant and applied continuously to the substrate. This higher content of photosynthesis pigments in the plant is possibly responsible for a greater absorption of N by the plant and, consequently, for better growth.Artículo Persulfidation of ATG18a regulates autophagy underER stress in Arabidopsis(National Academy of Sciences, 2021-05) Aroca Aguilar, Ángeles; Yruela Guerrero, Inmaculada; Gotor Martínez, Cecilia; Bassham, Diane C.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; European Union (UE). H2020; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Agencia Estatal de Investigación. España; National Institutes of Health. United StatesHydrogen sulfide (H2S) is an endogenously generated gaseous signaling molecule, which recently has been implicated in autophagy regulation in both plants and mammals through persulfidation of specific targets. Persulfidation has been suggested as the molecular mechanism through which sulfide regulates autophagy in plant cells. ATG18a is a core autophagy component that is required for bulk autophagy and also for reticulophagy during endoplasmic reticulum (ER) stress. In this research, we revealed the role of sulfide in plant ER stress responses as a negative regulator of autophagy. We demonstrate that sulfide regulates ATG18a phospholipid-binding activity by reversible persulfidation at Cys103, and that this modification activates ATG18a binding capacity to specific phospholipids in a reversible manner. Our findings strongly suggest that persulfidation of ATG18a at C103 regulates autophagy under ER stress, and that the impairment of persulfidation affects both the number and size of autophagosomes.Artículo PCNA molecular recognition of different PIP motifs: Role of Tyr211 phosphorylation(Elsevier, 2024-07) Ruiz Albor, Antonio; Chaves Arquero, Belén; Martín Barros, Inés; Guerra Castellano, Alejandra; González-Magaña, Amaia; Ibáñez de Okapua, Alain; Merino, Nekane; Ferreras Gutiérrez, Mariola; Berra, Edurne; Díaz Moreno, Irene; Blanco, Francisco J.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía; Consejo Superior de Investigaciones Científicas (CSIC)The coordination of enzymes and regulatory proteins for eukaryotic DNA replication and repair is largely achieved by Proliferating Cell Nuclear Antigen (PCNA), a toroidal homotrimeric protein that embraces the DNA duplex. Many proteins bind PCNA through a conserved sequence known as the PCNA interacting protein motif (PIP). PCNA is further regulated by different post-translational modifications. Phosphorylation at residue Y211 facilitates unlocking stalled replication forks to bypass DNA damage repair processes but increasing nucleotide misincorporation. We explore here how phosphorylation at Y211 affects PCNA recognition of the canonical PIP sequences of the regulatory proteins p21 and p15, which bind with nM and μM affinity, respectively. For that purpose, we have prepared PCNA with p-carboxymethyl-L-phenylalanine (pCMF, a mimetic of phosphorylated tyrosine) at position 211. We have also characterized PCNA binding to the non-canonical PIP sequence of the catalytic subunit of DNA polymerase δ (p125), and to the canonical PIP sequence of the enzyme ubiquitin specific peptidase 29 (USP29) which deubiquitinates PCNA. Our results show that Tyr211 phosphorylation has little effect on the molecular recognition of p21 and p15, and that the PIP sequences of p125 and USP29 bind to the same site on PCNA as other PIP sequences, but with very low affinity.Artículo A splice-altering homozygous variant in COX18 causes severe sensory-motor neuropathy with oculofacial apraxia(Elsevier B.V., 2024-10) Mavillard, Fabiola; Guerra Castellano, Alejandra; Guerrero Gómez, David; Rivas, Eloy; Cantero, Gloria; Servián Morilla, Emilia; Folland, Chiara; Ravenscroft, Gianina; Martín, Miguel A.; Miranda Vizuete, Antonio; Cabrera Serrano, Macarena; Díaz Moreno, Irene; Paradas, Carmen; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Instituto de Salud Carlos III; Junta de Andalucía; European Union (UE); Ministerio de Ciencia e Innovación (MICIN). EspañaCytochrome-c oxidase (COX) is part of the mitochondrial complex IV (CIV). COX deficiency is usually associated with tRNA variants, and less frequently with variants in COX assembly factors. Mutations in COX subunits encoded by mitochondrial DNA and nuclear DNA are rare, likely because most of them are associated to very severe phenotypes with early lethality. COX18, an assembly factor of CIV, has long been analyzed as a potential cause of mitochondrial disease. To date, only one patient has been identified carrying a homozygous missense variant in COX18, associated with neonatal encephalo-cardiomyopathy and axonal sensory neuropathy. Here, we describe a 40-year-old patient, asymptomatic until 7 months of age, who presented with progressive muscle weakness resembling spinal muscle atrophy type-2, associated with oculofacial apraxia and dysarthric speech. Electrophysiology analysis highlighted a severe sensory-motor neuropathy. Muscle biopsy showed striking and diffuse decreases of COX staining and a substantial reduction of CIV activity. Muscle biopsy showed no raggedred fibers, although ultrastructural mitochondrial alterations were evident. A novel homozygous variant (c.598G>A), located in the last nucleotide of exon 3, was detected in COX18 by whole-exome sequencing, which affected the splicing donor site, as demonstrated by cDNA-seq. The patient fibroblasts express a truncated form of COX18 (COX18Δ112-240) capable of assembling CIV and CIV-involving supercomplexes. However, CIV activity was decreased. COX18 full-length (COX18-fl) overexpression partially rescued CIV activity in the patient fibroblasts. The rescue of the null CIV activity in COX18-KO-HEK293 cells by overexpressing of COX18Δ112-240 was significantly lower than in cells with COX18-fl. In addition, cox-18 downregulation in C. elegans resulted in slow growth and, diminished reduced motility phenotypes and as well as severe fragmentation of the mitochondrial network. Our case expands the phenotypes associated with COX18 variants and supports the pathogenic role of COX18 as the cause of a severe encephaloneuropathy syndrome.Artículo Phosphorylation at the disordered N-end makes HuR accumulate and dimerize in the cytoplasm.(Oxford University Press, 2024-07-05) Baños Jaime, Blanca; Corrales Guerrero, Laura; Pérez Mejías, Gonzalo; Rejano Gordillo, Claudia M.; Velázquez Campoy, Adrián; Martínez Cruz, Luis Alfonso; Rosa Acosta, Miguel Ángel de la; Díaz Moreno, Irene; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Agencia Estatal de Investigación. España; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Junta de Andalucía; Universidad de Sevilla; Ministerio de Educación, Cultura y Deporte (MECD). EspañaHuman antigen R (HuR) is an RNA binding protein mainly involved in maintaining the stability and controlling the translation of mRNAs, critical for immune response, cell survival, proliferation and apoptosis. Although HuR is a nuclear protein, its mRNA translational-related function occurs at the cytoplasm, where the oligomeric form of HuR is more abundant. However, the regulation of nucleo-cytoplasmic transport of HuR and its connection with protein oligomerization remain unclear. In this work, we describe the phosphorylation of Tyr5 as a new hallmark for HuR activation. Our biophysical, structural and computational assays using phosphorylated and phosphomimetic HuR proteins demonstrate that phosphorylation of Tyr5 at the disordered N-end stretch induces global changes on HuR dynamics and conformation, modifying the solvent accessible surface of the HuR nucleo-cytoplasmic shuttling (HNS) sequence and releasing regions implicated in HuR dimerization. These findings explain the preferential cytoplasmic accumulation of phosphorylated HuR in HeLa cells, aiding to comprehend the mechanisms underlying HuR nucleus-cytoplasm shuttling and its later dimerization, both of which are relevant in HuR-related pathogenesis.Artículo Comparative Genomics of Synechococcus elongatus Explains the Phenotypic Diversity of the Strains(American Society for Microbiology, 2022) Adomako, Marie; Ernst, Dustin; Simkovsky, Ryan; Chao, Yi Yun; Wang, Jingtong; Fang, Mingxu; Bouchier, Christiane; López Igual, Rocío; Mazel, Didier; Gugger, Muriel; Golden, Susan S.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; National Institutes of Health. United StatesStrains of the freshwater cyanobacterium Synechococcus elongatus were first isolated approximately 60 years ago, and PCC 7942 is well established as a model for photosynthesis, circadian biology, and biotechnology research. The recent isolation of UTEX 3055 and subsequent discoveries in biofilm and phototaxis phenotypes suggest that lab strains of S. elongatus are highly domesticated. We performed a comprehensive genome comparison among the available genomes of S. elongatus and sequenced two additional laboratory strains to trace the loss of native phenotypes from the standard lab strains and determine the genetic basis of useful phenotypes. The genome comparison analysis provides a pangenome description of S. elongatus, as well as correction of extensive errors in the published sequence for the type strain PCC 6301. The comparison of gene sets and single nucleotide polymorphisms (SNPs) among strains clarifies strain isolation histories and, together with large-scale genome differences, supports a hypothesis of laboratory domestication. Prophage genes in laboratory strains, but not UTEX 3055, affect pigmentation, while unique genes in UTEX 3055 are necessary for phototaxis. The genomic differences identified in this study include previously reported SNPs that are, in reality, sequencing errors, as well as SNPs and genome differences that have phenotypic consequences. One SNP in the circadian response regulator rpaA that has caused confusion is clarified here as belonging to an aberrant clone of PCC 7942, used for the published genome sequence, that has confounded the interpretation of circadian fitness research.Artículo An Actin Remodeling Role for Arabidopsis Processing Bodies Revealed by their Proximity Interactome(WILEY, 2023) Liu, Chen; Mentzelopoulou, Andriani; Muhammad, Amna; Volkov, Andriy; Weijers, Dolf; Gutiérrez Beltrán, Emilio; Moschou, Panagiotis N.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Carl Tryggers Foundation; European Union (UE); Vetenskapsradet (VR) research council; FORMAS research council; Helge Ax:son Johnsons stiftelse; Hellenic Foundation of Research and Innovation (HFRI); European Research Council (ERC); Ministerio de Ciencia e Innovación (MICIN). EspañaCellular condensates can comprise membrane-less ribonucleoprotein assemblies with liquid-like properties. These cellular condensates influence various biological outcomes, but their liquidity hampers their isolation and characterization. Here, we investigated the composition of the condensates known as processing bodies (PBs) in the model plant Arabidopsis thaliana through a proximity-biotinylation proteomics approach. Using in situ protein–protein interaction approaches, genetics and high-resolution dynamic imaging, we show that processing bodies comprise networks that interface with membranes. Surprisingly, the conserved component of PBs, DECAPPING PROTEIN 1 (DCP1), can localize to unique plasma membrane subdomains including cell edges and vertices. We characterized these plasma membrane interfaces and discovered a developmental module that can control cell shape. This module is regulated by DCP1, independently from its role in decapping, and the actin-nucleating SCAR–WAVE complex, whereby the DCP1–SCAR–WAVE interaction confines and enhances actin nucleation. This study reveals an unexpected function for a conserved condensate at unique membrane interfaces.Artículo Glycogen synthesis prevents metabolic imbalance and disruption of photosynthetic electron transport from photosystem II during transition to photomixotrophy in Synechocystis sp. PCC 6803(John Wiley & Sons, 2024-05-06) Ortega Martínez, Pablo; Nikkanen, Lauri; Wey, Laura T.; Florencio Bellido, Francisco Javier; Allahverdiyeva, Yagut; Díaz Troya, Sandra; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía; NordForsk Nordic Center of Excellence; Novo Nordisk Foundation; Ministerio de Universidades. EspañaSome cyanobacteria can grow photoautotrophically or photomixotrophically by using simultaneously CO2 and glucose. The switch between these trophic modes and the role of glycogen, their main carbon storage macromolecule, was investigated. We analysed the effect of glucose addition on the physiology, metabolic and photosynthetic state of Synechocystis sp. PCC 6803 and mutants lacking phosphoglucomutase and ADP-glucose pyrophosphorylase, with limitations in glycogen synthesis. Glycogen acted as a metabolic buffer: glucose addition increased growth and glycogen reserves in the wild-type (WT), but arrested growth in the glycogen synthesis mutants. Already 30 min after glucose addition, metabolites from the Calvin–Benson–Bassham cycle and the oxidative pentose phosphate shunt increased threefold more in the glycogen synthesis mutants than the WT. These alterations substantially affected the photosynthetic performance of the glycogen synthesis mutants, as O2 evolution and CO2 uptake were both impaired. We conclude that glycogen synthesis is essential during transitions to photomixotrophy to avoid metabolic imbalance that induces inhibition of electron transfer from PSII and subsequently accumulation of reactive oxygen species, loss of PSII core proteins, and cell death. Our study lays foundations for optimising photomixotrophy-based biotechnologies through understanding the coordination of the crosstalk between photosynthetic electron transport and metabolism.Artículo Double blocking of carbon metabolism causes a large increase of Calvin–Benson cycle compounds in cyanobacteria(AMER SOC PLANT BIOLOGISTS; OXFORD UNIV PRESS INC, 2024) Domínguez Lobo, María Teresa; Roldán, Miguel; Gutiérrez Diánez, Alba María; Florencio Bellido, Francisco Javier; Muro Pastor, María Isabel; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia, Innovación y Universidades (MICINN). España; Agencia Estatal de Investigación. España; Junta de Andalucía; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)Carbon-flow-regulator A (CfrA) adapts carbon flux to nitrogen conditions in nondiazotrophic cyanobacteria. Under nitrogen deficiency, CfrA leads to the storage of excess carbon, which cannot combine with nitrogen, mainly as glycogen. cfrA overexpression from the arsenite-inducible, nitrogen-independent ParsB promoter allows analysis of the metabolic effects of CfrA accumulation. Considering that the main consequence of cfrA overexpression is glycogen accumulation, we examined carbon distribution in response to cfrA expression in Synechocystis sp. PCC 6803 strains impaired in synthesizing this polymer. We carried out a comparative phenotypic analysis to evaluate cfrA overexpression in the wild-type strain and in a mutant of ADP-glucose pyrophosphorylase (ΔglgC), which is unable to synthesize glycogen. The accumulation of CfrA in the wildtype background caused a photosynthetic readjustment although growth was not affected. However, in a ΔglgC strain, growth decreased depending on CfrA accumulation and photosynthesis was severely affected. An elemental analysis of the H, C, and N content of cells revealed that cfrA expression in the wild-type caused an increase in the C/N ratio, due to decreased nitrogen assimilation. Metabolomic study indicated that these cells store sucrose and glycosylglycerol, in addition to the previously described glycogen accumulation. However, cells deficient in glycogen synthesis accumulated large amounts of Calvin–Benson cycle intermediates as cfrA was expressed. These cells also showed increased levels of some amino acids, mainly alanine, serine, valine, isoleucine, and leucine. The findings suggest that by controlling cfrA expression, in different conditions and strains, we could change the distribution of fixed carbon, with potential biotechnological benefits.Artículo CONSTANS, a HUB for all seasons: How photoperiod pervades plant physiology regulatory circuits(AMER SOC PLANT BIOLOGISTS; OXFORD UNIV PRESS INC, 2024) Romero Rodríguez, José María; Serrano Bueno, Gloria; Camacho-Fernández, Carolina; Henrique Vicente, Mateus; Ruiz, María Teresa; Pérez Castiñeira, José Román; Pérez Hormaeche, Javier; Nogueira, Fabio; Valverde, Federico; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Union (UE)How does a plant detect the changing seasons and make important developmental decisions accordingly? How do they incorporate daylength information into their routine physiological processes?Photoperiodism, or the capacity to measure the daylength, is a crucial aspect of plant development that helps plants determine the best time of the year to make vital decisions, such as flowering. The protein CONSTANS (CO) constitutes the central regulator of this sensing mechanism, not only activating florigen production in the leaves but also participating in many physiological aspects in which seasonality is important. Recent discoveries place CO in the center of a gene network that can determine the length of the day and confer seasonal input to aspects of plant development and physiology as important as senescence, seed size, or circadian rhythms. In this review, we discuss the importance of CO protein structure, function, and evolutionary mechanisms that embryophytes have developed to incorporate annual information into their physiology.Artículo Cancer-Stem-Cell Phenotype-Guided Discovery of a Microbiota- Inspired Synthetic Compound Targeting NPM1 for Leukemia(AMER CHEMICAL SOC, 2023) Algar, Sergio; Vázquez-Villa, Henar; Aguilar-Garrido, Pedro; Navarro-Aguadero, Miguel Ángel; Velasco-Estévez, María; Sánchez-Merino, Anabel; Giner Arroyo, Rafael Luis; Tamargo Azpilicueta, Joaquín; Díaz Moreno, Irene; Benhamú, Bellinda; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); European Union (UE); Instituto de Salud Carlos III; Junta de AndalucíaThe human microbiota plays an important role in human health and disease, through the secretion of metabolites that regulate key biological functions. We propose that microbiota metabolites represent an unexplored chemical space of small druglike molecules in the search of new hits for drug discovery. Here, we describe the generation of a set of complex chemotypes inspired on selected microbiota metabolites, which have been synthesized using asymmetric organocatalytic reactions. Following a primary screening in CSC models, we identified the novel compound UCM-13369 (4b) whose cytotoxicity was mediated by NPM1. This protein is one of the most frequent mutations of AML, and NPM1-mutated AML is recognized by the WHO as a distinct hematopoietic malignancy. UCM-13369 inhibits NPM1 expression, downregulates the pathway associated with mutant NPM1 C+, and specifically recognizes the C-end DNA-binding domain of NPM1 C+, avoiding the nucleus-cytoplasm translocation involved in the AML tumorological process. The new NPM1 inhibitor triggers apoptosis in AML cell lines and primary cells from AML patients and reduces tumor infiltration in a mouse model of AML with NPM1 C+ mutation. The disclosed phenotype-guided discovery of UCM-13369, a novel small molecule inspired on microbiota metabolites, confirms that CSC death induced by NPM1 inhibition represents a promising therapeutic opportunity for NPM1-mutated AML, a high-mortality disease.Artículo 2-Cys peroxiredoxins contribute to thylakoid lipid unsaturation by affecting ω-3 fatty acid desaturase 8(AMER SOC PLANT BIOLOGISTS; OXFORD UNIV PRESS INC, 2024-02-22) Hernández Jiménez, María Luisa; Jiménez López, Julia; Cejudo Fernández, Francisco Javier; Pérez Ruiz, Juan Manuel; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; National Institutes of Health. United States; USDA National Institute of Food and AgricultureFatty acid unsaturation levels affect chloroplast function and plant acclimation to environmental cues. However, the regulatory mechanism(s) controlling fatty acid unsaturation in thylakoid lipids is poorly understood. Here, we have investigated the connection between chloroplast redox homeostasis and lipid metabolism by focusing on 2-Cys peroxiredoxins (Prxs), which play a central role in balancing the redox state within the organelle. The chloroplast redox network relies on NADPH-dependent thioredoxin reductase C (NTRC), which controls the redox balance of 2-Cys Prxs to maintain the reductive activity of redox-regulated enzymes. Our results show that Arabidopsis (Arabidopsis thaliana) mutants deficient in 2-Cys Prxs contain decreased levels of trienoic fatty acids, mainly in chloroplast lipids, indicating that these enzymes contribute to thylakoid membrane lipids unsaturation. This function of 2-Cys Prxs is independent of NTRC, the main reductant of these enzymes, hence 2-Cys Prxs operates beyond the classic chloroplast regulatory redox system. Moreover, the effect of 2-Cys Prxs on lipid metabolism is primarily exerted through the prokaryotic pathway of glycerolipid biosynthesis and fatty acid desaturase 8 (FAD8). While 2-Cys Prxs and FAD8 interact in leaf membranes as components of a large protein complex, the levels of FAD8 were markedly decreased when FAD8 is overexpressed in 2-Cys Prxs- deficient mutant backgrounds. These findings reveal a function for 2-Cys Prxs, possibly acting as a scaffold protein, affecting the unsaturation degree of chloroplast membranes.Artículo Microalgae, seaweeds and aquatic bacteria, archaea, and yeasts: sources of carotenoids with potential antioxidant and anti-inflammatory health-promoting actions in the sustainability era.(MDPI, 2023-06-01) Mapelli Brahm, Paula; Gómez Villegas, Patricia; Gonda, Mariana Lourdes; León Vaz, Antonio; León, Rosa; Mildenberger, Jennifer; Meléndez Martínez, Antonio Jesús; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Universidad de Sevilla. Departamento de Nutrición y Bromatología, Toxicología y Medicina Legal; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. España; Junta de Andalucía; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla. AGR225: Color y Calidad de AlimentosCarotenoids are a large group of health-promoting compounds used in many industrial sectors, such as foods, feeds, pharmaceuticals, cosmetics, nutraceuticals, and colorants. Considering the global population growth and environmental challenges, it is essential to find new sustainable sources of carotenoids beyond those obtained from agriculture. This review focuses on the potential use of marine archaea, bacteria, algae, and yeast as biological factories of carotenoids. A wide variety of carotenoids, including novel ones, were identified in these organisms. The role of carotenoids in marine organisms and their potential health-promoting actions have also been discussed. Marine organisms have a great capacity to synthesize a wide variety of carotenoids, which can be obtained in a renewable manner without depleting natural resources. Thus, it is concluded that they represent a key sustainable source of carotenoids that could help Europe achieve its Green Deal and Recovery Plan. Additionally, the lack of standards, clinical studies, and toxicity analysis reduces the use of marine organisms as sources of traditional and novel carotenoids. Therefore, further research on the processing of marine organisms, the biosynthetic pathways, extraction procedures, and examination of their content is needed to increase carotenoid productivity, document their safety, and decrease costs for their industrial implementation.Artículo Emerging nitrogen-fixing cyanobacteria for sustainable cotton cultivation(Elsevier, 2024-05-10) Jiménez Ríos, Lucía; Torrado Maya, Alejandro; González Pimentel, José Luis; Iniesta Pallarés, Macarena; Molina Heredia, Fernando Publio; Mariscal, Vicente; Álvarez Núñez, Consolación; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Corporación Tecnológica de Andalucía; Junta de AndalucíaAmid growing environmental concerns and the imperative for sustainable agricultural practices, this study examines the potential of nitrogen-fixing cyanobacteria as biofertilizers, particularly in cotton cultivation. The reliance on synthetic nitrogen fertilizers (SNFs), prevalent in modern agriculture, poses significant environmental challenges, including greenhouse gas emissions and water system contamination. This research aims to shift this paradigm by exploring the capacity of cyanobacteria as a natural and sustainable alternative. Utilizing advanced metabarcoding methods to analyze the 16S rRNA gene, we conducted a comprehensive assessment of soil bacterial communities within cotton fields. This study focused on evaluating the diversity, structure, taxonomic composition, and potential functional characteristics of these communities. Emphasis was placed on the isolation of native N2-fixing cyanobacteria strains rom cotton soils, and their subsequent effects on cotton growth. Results from our study demonstrate significant plant growth-promoting (PGP) activities, measured as N2 fixation, production of Phytohormones, Fe solubilization and biofertilization potential of five isolated cyanobacterial strains, underscoring their efficacy in cotton. These findings suggest a viable pathway for replacing chemical-synthetic nitrogen fertilizers with natural, organic alternatives. The reintegration of these beneficial species into agricultural ecosystems can enhance crop growth while fostering a balanced microbial environment, thus contributing to the broader goals of global sustainable agriculture.
Artículo MipZ caps the plus-end of FtsZ polymers to promote their rapid disassembly(NAS, 2022-12-09) Corrales Guerrero, Laura; Steinchen, Wieland; Ramm, Beatrice; Mücksch, Jonas; Rosum, Julia; Refes, Yacine; Heimerl, Thomas; Bange, Gert; Schwille, Petra; Thanbichler, Martin; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Deutsche Forschungsgemeinschaft / German Research Foundation (DFG)The spatiotemporal regulation of cell division is a fundamental issue in cell biology. Bacteria have evolved a variety of different systems to achieve proper division site placement. In many cases, the underlying molecular mechanisms are still incompletely understood. In this study, we investigate the function of the cell division regulator MipZ from Caulobacter crescentus, a P-loop ATPase that inhibits the polymerization of the treadmilling tubulin homolog FtsZ near the cell poles, thereby limiting the assembly of the cytokinetic Z ring to the midcell region. We show that MipZ interacts with FtsZ in both its monomeric and polymeric forms and induces the disassembly of FtsZ polymers in a manner that is not dependent but enhanced by the FtsZ GTPase activity. Using a combination of biochemical and genetic approaches, we then map the MipZ–FtsZ interaction interface. Our results reveal that MipZ employs a patch of surface-exposed hydrophobic residues to interact with the C-terminal region of the FtsZ core domain. In doing so, it sequesters FtsZ monomers and caps the (+)-end of FtsZ polymers, thereby promoting their rapid disassembly. We further show that MipZ influences the conformational dynamics of interacting FtsZ molecules, which could potentially contribute to modulating their assembly kinetics. Together, our findings show that MipZ uses a combination of mechanisms to control FtsZ polymerization, which may be required to robustly regulate the spatiotemporal dynamics of Z ring assembly within the cell.Artículo A protease-mediated mechanism regulates the cytochrome c6/plastocyanin switch in Synechocystis sp. PCC 6803(NAS, 2021-01-25) García Cañas, Raquel María; Giner Lamia, Joaquín; Florencio Bellido, Francisco Javier; López Maury, Luis; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Economia, Industria y Competitividad (MINECO). España; Agencia Estatal de Investigación. España; Junta de Andalucía; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)After the Great Oxidation Event (GOE), iron availability was greatly decreased, and photosynthetic organisms evolved several alternative proteins and mechanisms. One of these proteins, plastocyanin, is a type I blue-copper protein that can replace cytochrome c6 as a soluble electron carrier between cytochrome b6f and photosystem I. In most cyanobacteria, expression of these two alternative proteins is regulated by copper availability, but the regulatory system remains unknown. Herein, we provide evidence that the regulatory system is composed of a BlaI/CopY-family transcription factor (PetR) and a BlaR-membrane protease (PetP). PetR represses petE (plastocyanin) expression and activates petJ (cytochrome c6), while PetP controls PetR levels in vivo. Using whole-cell extracts, we demonstrated that PetR degradation requires both PetP and copper. Transcriptomic analysis revealed that the PetRP system regulates only four genes (petE, petJ, slr0601, and slr0602), highlighting its specificity. Furthermore, the presence of petE and petRP in early branching cyanobacteria indicates that acquisition of these genes could represent an early adaptation to decreased iron bioavailability following the GOE.Artículo The Functional Relationship between NADPH Thioredoxin Reductase C, 2-Cys Peroxiredoxins, and m-Type Thioredoxins in the Regulation of Calvin–Benson Cycle and Malate-Valve Enzymes in Arabidopsis(Multidisciplinary Digital Publishing Institute (MDPI), 2023-05-03) Delgado Requerey, Víctor; Cejudo Fernández, Francisco Javier; González García, María de la Cruz; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Junta de AndalucíaThe concerted regulation of chloroplast biosynthetic pathways and NADPH extrusion via malate valve depends on f and m thioredoxins (Trxs). The finding that decreased levels of the thiol-peroxidase 2-Cys peroxiredoxin (Prx) suppress the severe phenotype of Arabidopsis mutants lacking NADPH-dependent Trx reductase C (NTRC) and Trxs f uncovered the central function of the NTRC-2-Cys-Prx redox system in chloroplast performance. These results suggest that Trxs m are also regulated by this system; however, the functional relationship between NTRC, 2-Cys Prxs, and m-type Trxs is unknown. To address this issue, we generated Arabidopsis thaliana mutants combining deficiencies in NTRC, 2-Cys Prx B, Trxs m1, and m4. The single trxm1 and trxm4 mutants showed a wild-type phenotype, growth retardation being noticed only in the trxm1m4 double mutant. Moreover, the ntrc-trxm1m4 mutant displayed a more severe phenotype than the ntrc mutant, as shown by the impaired photosynthetic performance, altered chloroplast structure, and defective light-dependent reduction in the Calvin–Benson cycle and malate-valve enzymes. These effects were suppressed by the decreased contents of 2-Cys Prx, since the quadruple ntrc-trxm1m4-2cpb mutant displayed a wild-type-like phenotype. These results show that the activity of m-type Trxs in the light-dependent regulation of biosynthetic enzymes and malate valve is controlled by the NTRC-2-Cys-Prx system.Artículo The contribution of glutathione peroxidases to chloroplast redox homeostasis in Arabidopsis(Elsevier, 2023-07) Casatejada Pérez, María Azahara; Puerto Galán, Leonor; Pérez Ruiz, Juan Manuel; Cejudo Fernández, Francisco Javier; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Ministerio de UniversidadesOxidizing signals mediated by the thiol-dependent peroxidase activity of 2-Cys peroxiredoxins (PRXs) plays an essential role in fine-tuning chloroplast redox balance in response to changes in light intensity, a function that depends on NADPH-dependent thioredoxin reductase C (NTRC). In addition, plant chloroplasts are equipped with glutathione peroxidases (GPXs), thiol-dependent peroxidases that rely on thioredoxins (TRXs). Despite having a similar reaction mechanism than 2-Cys PRXs, the contribution of oxidizing signals mediated by GPXs to the chloroplast redox homeostasis remains poorly known. To address this issue, we have generated the Arabidopsis (Arabidopsis thaliana) double mutant gpx1gpx7, which is devoid of the two GPXs, 1 and 7, localized in the chloroplast. Furthermore, to analyze the functional relationship of chloroplast GPXs with the NTRC-2-Cys PRXs redox system, the 2cpab-gpx1gpx7 and ntrc-gpx1gpx7 mutants were generated. The gpx1gpx7 mutant displayed wild type-like phenotype indicating that chloroplast GPXs are dispensable for plant growth at least under standard conditions. However, the 2cpab-gpx1gpx7 showed more retarded growth than the 2cpab mutant. The simultaneous lack of 2-Cys PRXs and GPXs affected PSII performance and caused higher delay of enzyme oxidation in the dark. In contrast, the ntrc-gpx1gpx7 mutant combining the lack of NTRC and chloroplast GPXs behaved like the ntrc mutant indicating that the contribution of GPXs to chloroplast redox homeostasis is independent of NTRC. Further supporting this notion, in vitro assays showed that GPXs are not reduced by NTRC but by TRX y2. Based on these results, we propose a role for GPXs in the chloroplast redox hierarchy.