Artículos (Bioquímica Vegetal y Biología Molecular)
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Artículo Transcriptomic analysis reveals the participation of NTRC in iron homeostasis in Arabidopsis(Wiley, 2025-04-10) Rodríguez Marín, Fernando; Pérez Ruiz, Juan Manuel; Cejudo Fernández, Francisco Javier; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia, Innovación y Universidades (MICIU). España; Agencia Estatal de Investigación. EspañaNADPH-dependent thioredoxin reductase C (NTRC) plays a central role in redox regulation of chloroplast photosynthetic metabolism. Accordingly, Arabidopsis (Arabidopsis thaliana) NTRC-null mutants show defective photosynthetic performance and growth inhibition. Remarkably, these mutants show almost a wild-type phenotype at the seedling stage, which raises the question of whether NTRC plays different functions throughout plant development. In this work, we have addressed this issue by performing transcriptome comparisons of Arabidopsis wild-type and ntrc mutant lines at seedling and adult stages of development. In contrast with the high impact of NTRC on leaves from adult plants, the low transcriptomic differences in seedlings suggested a less relevant function of NTRC at this stage of plant development. Notably, the ntrc mutant showed transcriptomic changes resembling the response to Fe excess throughout plant development, though this response was almost unique at the seedling stage. The lack of NTRC caused altered levels of Mn, Zn, Cu, S, P, K and Na, but no significant differences in the content of Fe, as compared with the wild type. Moreover, at the seedling stage, the lack of NTRC caused hypersensitivity to Fe deficit but a protective effect in response to Fe excess, most likely due to lower ROS accumulation in the mutant seedlings. Our results reveal the different impacts of NTRC throughout plant development and identify Fe homeostasis as a process highly affected by NTRC, most notably at the seedling stage.
Artículo Applying an NMR-based metabolomic workflow to unveil strawberry molecular mechanisms in vernalization(Elsevier, 2025-03-31) Fernández Veloso, Andrea; Hiniesta Valero, Jaime; Guerra Castellano, Alejandra; Tomás Gallardo, Laura; Rosa Acosta, Miguel Ángel de la; Díaz Moreno, Irene; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; European Union (UE)Nuclear Magnetic Resonance (NMR) is a mature technique in metabolomics due to its non-invasive, highly reproducible, and inherently quantitative nature. However, difficulties in data analysis hinder its standardization in research. Herein, we propose an NMR-based metabolomic workflow that comprises data preprocessing, metabolite annotation, and data analysis. In this work, we apply such workflow to study vernalization, which is a critical process for crop development with largely unknown molecular mechanisms. Our findings suggest that sugar mobility, accessibility, and increased photosynthetic activity support plant viability post-vernalization. In other words, these processes ensure successful transplanting of the plant, highlighting the importance of sufficient cold exposure for flowering, fruiting, and ripening. This study demonstrates that the proposed workflow is suitable to capture metabolic changes in plant development. Such methodology underscores the potential of NMR-based metabolomics as a powerful tool for crop monitoring, aiding in improved agricultural practices and yield optimization.Artículo A machine learning-based nuclear magnetic resonance profiling model to authenticate ’Jerez-Xérès-Sherry’ wines(Elsevier, 2025-03-26) Hiniesta Valero, Jaime; Guerra Castellano, Alejandra; Fernández Veloso, Andrea; Rosa Acosta, Miguel Ángel de la; Díaz Moreno, Irene; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología MolecularTraditionally, wine quality and certification have been assessed through sensory analysis by trained tasters. However, this method has the limitation of relying on highly specialized individuals who are typically trained to evaluate only specific types of products, such as those associated with a particular Denomination of Origin (D.O.), etc. While tasters can often identify instances of fraud, they are generally unable to pinpoint its origins or explain the mechanisms behind it. On the other hand, classical biochemistry has made significant progress in understanding various aspects of winemaking. However, it has yet to identify the specific metabolites responsible for the unique characteristics of wines, particularly those influenced by complex variables involving multiple compounds, such as geographical differences between regions or vineyards. The concept of the “Terroir fingerprint” has emerged as a novel approach to wine certification. The concept refers to the unique characteristics imparted to a wine by its geography, climate, and aging process. Nuclear Magnetic Resonance (NMR) technology plays a pivotal role in establishing this “Terroir fingerprint” because it enables precise identification, quantification, and differentiation of the compounds present in wine. NMR provides a highly reproducible and specific method for certification. This work introduces an innovative project that combines NMR technology with Artificial Intelligence to create a profiling model for certifying the authenticity and quality of ‘Jerez-Xérès-Sherry’ wines.Artículo PharaohFUN: PHylogenomic Analysis foR plAnt prOtein History and FUNction elucidation(2023) Ramos González, Marcos; Ramos González, Víctor; Arvanitidou, Christina; Hernández García, Jorge; García González, Mercedes; Romero Campero, Francisco José; Universidad de Sevilla. Departamento de Ciencias de la Computación e Inteligencia Artificial; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología MolecularMotivation Since DNA sequencing has turned commonplace, the development of efficient methods and tools to explore gene sequences has become indispensable. In particular, despite photosynthetic eukaryotes constituting the largest percentage of terrestrial biomass, computational functional characterization of gene sequences in these organisms still predominantly relies on comparisons with Arabidopsis thaliana and other angiosperms. This paper introduces PharaohFUN, a web application designed for the evolutionary and functional analysis of protein sequences in photosynthetic eukaryotes, leveraging orthology relationships between them. Results PharaohFUN incorporates a homogeneous representative sampling of key species in this group, bridging clades that have traditionally been studied separately, thus establishing a comprehensive evolutionary framework to draw conclusions about sequence evolution and function. For this purpose, it incorporates modules for exploring gene tree evolutionary history, domain identification, multiple sequence alignments, and functional annotation. The study of the CCA1 protein exemplifies how PharaohFUN unifies results for both land plants and chlorophyte microalgae, accurately tracing the evolutionary history of this protein.Artículo Multiomics responses to seasonal variations in diel cycles in the marine phytoplanktonic picoeukaryoteOstreococcus tauri(2023-08) Romero Losada, Ana Belén; Arvanitidou, Christina; García Gómez, María Elena; Morales Pineda, María; Castro Pérez, M. José; García González, Mercedes; Romero Campero, Francisco José; Universidad de Sevilla. Departamento de Ciencias de la Computación e Inteligencia Artificial; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología MolecularEarth tilted rotation and translation around the Sun produce one of the most pervasive periodic environmental signals on our planet giving rise to seasonal variations in diel cycles. Although marine phytoplankton plays a key role on ecosystems and present promising biotechnological applications, multiomics integrative analysis of their response to these rhythms remains largely unexplored. We have chosen the marine picoeukaryote Ostreococcus tauri as model organism grown under summer long days, winter short days, constant light and constant dark conditions to characterize these responses in marine phytoplankton. Although 80% of the transcriptome present diel rhythmicity under both seasonal conditions less than 5% maintained oscillations under all constant conditions. A drastic reduction in protein abundance rhythmicity was observed with 55% of the proteome oscillating. Seasonally specific rhythms were found in key physiological processes such as cell cycle progression, photosynthetic efficiency, carotenoid content, starch accumulation and nitrogen assimilation. A global orchestration between transcriptome, proteome and physiological dynamics was observed with specific seasonal temporal offsets between transcript, protein and physiological peaks.Artículo Multiomics integration unveils photoperiodic plasticity in the molecular rhythms of marine phytoplankton(Oxford University Press, 2025-02-11) Romero Losada, Ana Belén; Arvanitidou, Christina; García-Gómez, M.E.; Morales-Pineda, M.; Castro-Pérez, M.J.; Chew, Y.P.; van Ooijen, G.; García González, Mercedes; Romero Campero, Francisco José; Universidad de Sevilla. Departamento de Ciencias de la Computación e Inteligencia Artificial; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). EspañaEarth’s tilted rotation and translation around the Sun produce pervasive rhythms on our planet, giving rise to photoperiodic changes in diel cycles. Although marine phytoplankton plays a key role in ecosystems, multiomics analysis of its responses to these periodic environmental signals remains largely unexplored. The marine picoalga Ostreococcus tauri was chosen as a model organism due to its cellular and genomic simplicity. Ostreococcus was subjected to different light regimes to investigate its responses to periodic environmental signals: long summer days, short winter days, constant light, and constant dark conditions. Although <5% of the transcriptome maintained oscillations under both constant conditions, 80% presented diel rhythmicity. A drastic reduction in diel rhythmicity was observed at the proteome level, with 39% of the detected proteins oscillating. Photoperiod-specific rhythms were identified for key physiological processes such as the cell cycle, photosynthesis, carotenoid biosynthesis, starch accumulation, and nitrate assimilation. In this study, a photoperiodic plastic global orchestration among transcriptome, proteome, and physiological dynamics was characterized to identify photoperiod-specific temporal offsets between the timing of transcripts, proteins, and physiological responses.Artículo Cytochrome c prompts the recruitment of its nuclear partners SET/TAF-Iβ and NPM1 into biomolecular condensates(Cell Press, 2024-07-02) Casado Combreras, Miguel Ángel; Velázquez Campoy, Adrián; Martinho, Marlène; Belle, Valérie; 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; European Cooperation in Science and Technology (COST); University of CaliforniaCompartmentalization of proteins by liquid-liquid phase separation (LLPS) is used by cells to control biochemical reactions spatially and temporally. Among them, the recruitment of proteins to DNA foci and nucleolar trafficking occur by biomolecular condensation. Within this frame, the oncoprotein SET/ TAF-Ib plays a keyrole in bothchromatin remodelingandDNAdamageresponse,asdoesnucleophosmin (NPM1)whichindeedparticipatesinnucleolar ribosome synthesis. Whereasphase separation byNPM1is widelycharacterized,little is known aboutthatundergonebySET/TAF-Ib.Here,weshowthatSET/TAF-Ib experiences phase separation together with respiratory cytochrome c (Cc), which translocates to the nucleus upon DNA damage. Here we report the molecular mechanisms governing Cc-induced phase separation of SET/TAF-IbandNPM1,wheretwolysine-richclustersofCcareessentialtorecognizemolecular surfaces on both partners in a specific and coordinated manner. Cc thus emerges as a small, globular protein with sequence-encoded heterotypic phase-separation propertiesArtículo Antioxidant Responses and Redox Regulation Within Plant-Beneficial Microbe Interaction(Multidisciplinary Digital Publishing Institute (MDPI), 2024-12-18) González García, María de la Cruz; Roitsch, Thomas; Pandey, Chandana; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Novo Nordisk Foundation; Ministry of Education, Youth and Sports of the Czech RepublicThe increase in extreme climate events associated with global warming is a great menace to crop productivity nowadays. In addition to abiotic stresses, warmer conditions favor the spread of infectious diseases affecting plant performance. Within this context, beneficial microbes constitute a sustainable alternative for the mitigation of the effects of climate change on plant growth and productivity. Used as biostimulants to improve plant growth, they also increase plant resistance to abiotic and biotic stresses through the generation of a primed status in the plant, leading to a better and faster response to stress. In this review, we have focused on the importance of a balanced redox status for the adequate performance of the plant and revisited the different antioxidant mechanisms supporting the biocontrol effect of beneficial microbes through the adjustment of the levels of reactive oxygen species (ROS). In addition, the different tools for the analysis of antioxidant responses and redox regulation have been evaluated. The importance of redox regulation in the activation of the immune responses through different mechanisms, such as transcriptional regulation, retrograde signaling, and post-translational modification of proteins, emerges as an important research goal for understanding the biocontrol activity of the beneficial microbes.Artículo Sulfuro de hidrógeno: de gas tóxico a molécula necesaria para vivir(Universidad de Málaga, 2018-02-18) Aroca Aguilar, Ángeles; Gotor Martínez, Cecilia; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Junta de Andalucía; Agencia Estatal de Investigación. EspañaEl sulfuro de hidrógeno siempre se ha considerado un gas nocivo. Sin embargo, investigaciones recientes han desvelado sus propiedades bioquímicas beneficiosas y su papel como molécula de señalización en numerosos procesos fisiológicos y patológicos tanto en animales como en plantas. Diversos estudios demuestran el papel protector del sulfuro de hidrógeno frente al estrés oxidativo; y tanto en sistemas animales como vegetales se ha descrito que el sulfuro de hidrógeno está implicado en la regulación de la autofagia, cuyo mecanismo de acción subyacente es la persulfuración de dianas específicas, con el objetivo de promover la supervivencia del organismo.Artículo Seed longevity is controlled by metacaspases(Nature Research, 2024-08-08) Liu, Chen; Hatzianestis, Ioannis H.; Pfirrmann, Thorsten; Reza, Salim H.; Minina, Elena A.; Moazzami, Ali; Gutiérrez Beltrán, Emilio; Romero Campero, Francisco José; Moschou, Panagiotis N.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; European Union (UE). H2020; European Research Council (ERC)To survive extreme desiccation, seeds enter a period of quiescence that can last millennia. Seed quiescence involves the accumulation of protective storage proteins and lipids through unknown adjustments in protein homeostasis (proteostasis). Here, we show that mutation of all six type–II metacaspase (MCA–II) proteases in Arabidopsis thaliana disturbs proteostasis in seeds. MCA–II mutant seeds fail to restrict the AAA ATPase CELL DIVISION CYCLE 48 (CDC48) at the endoplasmic reticulum to discard misfolded proteins, compromising seed storability. Endoplasmic reticulum (ER) localization of CDC48 relies on the MCA–IIs-dependent cleavage of PUX10 (ubiquitination regulatory X domain–containing 10), the adaptor protein responsible for titrating CDC48 to lipid droplets. PUX10 cleavage enables the shuttling of CDC48 between lipid droplets and the ER, providing an important regulatory mechanism sustaining spatiotemporal proteolysis, lipid droplet dynamics, and protein homeostasis. In turn, the removal of the PUX10 adaptor in MCA–II mutant seeds partially restores proteostasis, CDC48 localization, and lipid droplet dynamics prolonging seed lifespan. Taken together, we uncover a proteolytic module conferring seed longevityArtículo Non-Canonical, Extralysosomal Activities of Lysosomal Peptidases in Physiological and Pathological Conditions: New Clinical Opportunities for Cancer Therapy(Multidisciplinary Digital Publishing Institute (MDPI), 2025-01-07) Conesa Bakkali, Ryan; Morillo Huesca, Macarena; Martínez Fábregas, Jonathan; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Junta de Andalucía; European Union (UE); Ministerio de Ciencia e Innovación (MICIN). España; Universidad de SevillaLysosomes are subcellular compartments characterised by an acidic pH, containing an ample variety of acid hydrolases involved in the recycling of biopolymers. Among these hydrolases, lysosomal proteases have merely been considered as end-destination proteases responsible for the digestion of waste proteins, trafficked to the lysosomal compartment through autophagy and endocytosis. However, recent reports have started to unravel specific roles for these proteases in the regulation of initially unexpected biological processes, both under physiological and pathological conditions. Furthermore, some lysosomal proteases are no longer restricted to the lysosomal compartment, as more novel non-canonical, extralysosomal targets are being identified. Currently, lysosomal proteases are accepted to play key functions in the extracellular milieu, attached to the plasma membrane and even in the cytosolic and nuclear compartments of the cell. Under physiological conditions, lysosomal proteases, through non-canonical, extralysosomal activities, have been linked to cell differentiation, regulation of gene expression, and cell division. Under pathological conditions, these proteases have been linked to cancer, mostly through their extralysosomal activities in the cytosol and nuclei of cells. In this review, we aim to provide a comprehensive summary of our current knowledge about the extralysosomal, non-canonical functions of lysosomal proteases, both under physiological and pathological conditions, with a particular interest in cancer, that could potentially offer new opportunities for clinical intervention.Artículo R-DeeP/TripepSVM identifies the RNA-binding OB-fold-like protein PatR as regulator of heterocyst patterning(Oxford University Press, 2025-02-10) Brenes-Álvarez, Manuel; Ropp, Halie R.; Papagiannidis, Dimitrios; Potel, Clement M.; Stein, Frank; Scholz, Ingeborg; Steglich, Claudia; Savitski, Mikhail M.; Vioque Peña, Agustín; Muro Pastor, Alicia María; Hess, Wolfgang R.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Deutsche Forschungsgemeinschaft / German Research Foundation (DFG); Ministerio de Ciencia e Innovación (MICIN). EspañaRNA-binding proteins (RBPs) are central components of gene regulatory networks. The differentiation of heterocysts in filamentous cyanobacteria is an example of cell differentiation in prokaryotes. Although multiple non-coding transcripts are involved in this process, no RBPs have been implicated thus far. Here we used quantitative mass spectrometry to analyze the differential fractionation of RNA–protein complexes after RNase treatment in density gradients yielding 333 RNA-associated proteins, while a bioinformatic prediction yielded 311 RBP candidates in Nostoc sp. PCC 7120. We validated in vivo the RNA-binding capacity of six RBP candidates. Some participate in essential physiological aspects, such as photosynthesis (Alr2890), thylakoid biogenesis (Vipp1) or heterocyst differentiation (PrpA, PatU3), but their association with RNA was unknown. Validated RBPs Asl3888 and Alr1700 were not previously characterized. Alr1700 is an RBP with two oligonucleotide/oligosaccharide-binding (OB)-fold-like domains that is differentially expressed in heterocysts and interacts with non-coding regulatory RNAs. Deletion of alr1700 led to complete deregulation of the cell differentiation process, a striking increase in the number of heterocyst-like cells, and was ultimately lethal in the absence of combined nitrogen. These observations characterize this RBP as a master regulator of the heterocyst patterning and differentiation process, leading us to rename Alr1700 to PatR.Artículo Thioredoxin A regulates protein synthesis to maintain carbon and nitrogen partitioning in cyanobacteria.(American Society of Plant Biologists, 2024-02-22) Mallén Ponce, Manuel J.; Florencio Bellido, Francisco Javier; Huertas Romera, María José; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia, Innovación y Universidades (MICINN). España; Agencia Estatal de Investigación. España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Junta de Andalucía; Universidad de Sevilla; Universidad de Sevilla. BIO284: Expresión Génica y Regulación Metabólica en Cianobacterias.Thioredoxins play an essential role in regulating enzyme activity in response to environmental changes, especially in photosynthetic organisms. They are crucial for metabolic regulation in cyanobacteria, but the key redox-regulated central processes remain to be determined. Physiological, metabolic, and transcriptomic characterization of a conditional mutant of the essential Synechocystis sp. PCC 6803 thioredoxin trxA gene (STXA2) revealed that decreased TrxA levels alter cell morphology and induce a dormant-like state. Furthermore, TrxA depletion in the STXA2 strain inhibited protein synthesis and led to changes in amino acid pools and nitrogen/carbon reserve polymers, accompanied by oxidation of the elongation factor-Tu. Transcriptomic analysis of TrxA depletion in STXA2 revealed a robust transcriptional response. Downregulated genes formed a large cluster directly related to photosynthesis, ATP synthesis, and CO2 fixation. In contrast, upregulated genes were grouped into different clusters related to respiratory electron transport, carotenoid biosynthesis, amino acid metabolism, and protein degradation, among others. These findings highlight the complex regulatory mechanisms that govern cyanobacterial metabolism, where TrxA acts as a critical regulator that orchestrates the transition from anabolic to maintenance metabolism and regulates carbon and nitrogen balance.Artículo Mutational analysis of the inactivating factors, IF7 and IF17 from Synechocystis sp. PCC 6803: Critical role of arginine amino acid residues for glutamine synthetase inactivation(John Wiley & Sons, 2011-11) Saelices, Lorena; Galmozzi, Carla V.; Florencio Bellido, Francisco Javier; Muro Pastor, María Isabel; Universidad de Sevilla. Departamento de Genética; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Junta de AndalucíaThe Synechocystis sp. PCC 6803 glutamine synthetase type I (GS) activity is controlled by a process that involves protein-protein interaction with two inactivating factors (IF7 and IF17). IF7 is a natively unfolded, 65-residue-long protein, homologous to the carboxy-terminal region of IF17. Both proteins have abundance of positively charged amino acid residues and a high isoelectric point. In this study, we analyse the IF amino acid residues involved in GS inactivation by a mutational approach, both in vitro and in vivo. The results clearly indicate that the GS-IF complex formation must be determined mainly by electrostatic interactions. We have identified three conserved arginine residues of IF7 and IF17 that are essential for the interaction of these proteins with GS. All these residues map in the homologous region of IFs. Furthermore, in vitro analysis of a truncated IF17 protein without the 82-residue-long amino-terminal part, together with the analysis of a Synechocystis strain expressing a chimeric protein, containing this amino-terminal part of IF17 fused to IF7, demonstrates that amino-terminal region of IF17 mostly confers a higher stability to this protein.Artículo The inactivating factor of glutamine synthetase IF17 Is an intrinsically disordered protein, which folds upon binding to its target(American Chemical Society, 2011-10-12) Saelices, Lorena; Galmozzi, Carla V.; Florencio Bellido, Francisco Javier; Muro Pastor, María Isabel; Neira, José L.; Universidad de Sevilla. Departamento de Genética; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; Generalitat Valenciana; Junta de AndalucíaIn cyanobacteria, ammonium is incorporated into carbon skeletons by the sequential action of glutamine synthetase and glutamate synthase (GOGAT). The activity of Synechocystis sp. PCC 6803 glutamine synthetase type I (GS) is controlled by a post-transcriptional process involving protein-protein interactions with two inactivating factors: the 65-residue-long protein (IF7) and the 149-residue-long one (IF17). The sequence of the C terminus of IF17 is similar to IF7; IF7 is an intrinsically disordered protein (IDP). In this work, we study the structural propensities and affinity for GS of IF17 and a chimera protein, IF17N/IF7 (constructed by fusing the first 82 residues of IF17 with the whole IF7) by fluorescence, CD, and NMR. IF17 and IF17N/IF7 are IDPs with residual non-hydrogen-bonded structure, probably formed by α-helical, turn-like, and PPII conformations; several theoretical predictions support these experimental findings. IF17 seems to fold upon binding to GS, as suggested by CD thermal denaturations and steady-state far-UV spectra. The apparent affinity of IF17 for GS, as measured by fluorescence, is slightly smaller (K D ∼1 μM) than that measured for IF7 (∼0.3 μM). The K Ds determined by CD are similar to those measured by fluorescence, but slightly larger, suggesting possible conformational rearrangements in the IFs and/or GS upon binding. Further, the results with IFN17/IF7 suggest that (i) binding of IF17 to the GS is modulated not only by its C-terminal region but also by its N-terminus and (ii) there are weakly structured (that is, "fuzzy") complexes in the ternary GS-IF system.Artículo N and C control of ABC-type bicarbonate transporter Cmp and its LysR-type transcriptional regulator CmpR in a heterocyst-forming cyanobacterium, Anabaena sp.(Wiley, 2012-06-06) López Igual, Rocío; Picossi, S.; López-Garrido, J.; Flores, E.; Herrero, A.; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)In the model, heterocyst-forming cyanobacterium Anabaena sp. PCC 7120, gene cluster alr2877-alr2880, which encodes an ABC-type transport system, was induced under conditions of carbon limitation and its inactivation impaired the uptake of bicarbonate. Thus, this gene cluster encodes a Cmp bicarbonate transporter. ORF all0862, encoding a LysR-type transcriptional regulator, was expressed under carbon limitation and at higher levels in the absence than in the presence of combined nitrogen, with a positive effect of the N-control transcription factor NtcA. all0862 was expressed from two putative transcription start sites located 164 and 64 bp upstream from the gene respectively. The latter was induced under carbon limitation and was dependent on positive autoregulation by All0862. All0862 was required for the induction of the Cmp bicarbonate transporter, thus representing a CmpR regulator of Anabaena sp. These results show a novel mode of co-regulation by C and N availability through the concerted action of N- and C-responsive transcription factors.Artículo Green microbes: Potential solutions for key sustainable development goals(Wyley, 2024-07-26) Díaz Troya, Sandra; Huertas Romera, María José; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecularhe latest assessment of progress towards theSustainable Development Goals (SDGs) has identi-fied major obstacles, such as climate change, globalinstability and pandemics, which threaten effortsto achieve the SDGs even by 2050. Urgent actionis needed, particularly to reduce poverty, hungerand climate change. In this context, microalgae areemerging as a promising solution, particularly in thecontext of food security and environmental sustain-ability. As versatile organisms, microalgae offer nu-tritional benefits such as high- quality proteins andessential fatty acids, and can be cultivated in non-arable areas, reducing competition for resources andimproving the sustainability of food systems. The roleof microalgae also includes other applications in aq-uaculture, where they serve as sustainable alterna-tives to animal feed, and in agriculture, where theyact as biofertilizers and biostimulants. These micro-organisms also play a key role in interventions ondegraded land, stabilizing soils, improving hydrologi-cal function and increasing nutrient and carbon avail-ability. Microalgae therefore support several SDGsby promoting sustainable agricultural practices andcontributing to land restoration and carbon seques-tration efforts. The integration of microalgae in theseareas is essential to mitigate environmental impactsand improve global food security, highlighting theneed for increased research and development, aswell as public and political support, to exploit their fullpotential to advance the SDGsArtículo Functional dissection and evidence for intercellular transfer of the heterocyst-differentiation PatS morphogen(John Wiley & Sons, 2013-06) Corrales Guerrero, Laura; Mariscal Romero, Vicente; Flores, Enrique; Herrero, Antonia; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ministerio de Ciencia e Innovación (MICIN). EspañaThe formation of a diazotrophic cyanobacterial filament represents a simple example of biological development. In Anabaena, a non-random pattern of one nitrogen-fixing heterocyst separated by about 10 photosynthetic vegetative cells results from lateral inhibition elicited by the cells differentiating into heterocysts. Key to this process is the patS gene, which has been shown to produce an inhibitor of heterocyst differentiation that involves the C-terminal RGSGR pentapeptide. Complementation of a ΔpatSAnabaena mutant with different versions of PatS, including point mutations or tag fusions, showed that patS is translated into a 17-amino acid polypeptide. Alterations in the N-terminal part of PatS produced inhibition of heterocyst differentiation, thus this part of the peptide appears necessary for proper processing and self-immunity in the producing cells. Alterations in the C-terminal part of PatS led to over-differentiation, thus supporting its role in inhibition of heterocyst differentiation. A polypeptide, produced in proheterocysts, consisting of a methionine followed by the eight, but not the five, terminal amino acids of PatS recreated the full activity of the native peptide. Immunofluorescence detection showed that an RGSGR-containing peptide accumulated in the cells adjacent to the producing proheterocysts, illustrating intercellular transfer of a morphogen in the cyanobacterial filaments.Artículo Self-aggregation in Aqueous Solution of Amphiphilic Cationic Calix[4]arenes. Potential Use as Vectors and Nanocarriers(Elsevier, 2020) Ostos Marcos, Francisco José; Lebrón Romero, José Antonio; López-Cornejo, María del Pilar; López López, Manuel; García Calderón, Margarita; García Calderón, Clara Beatriz; Valle Rosado, Iván; Kalchenko, Vitaly I.; Rodik, Roman V.; Moyá Morán, María Luisa; Universidad de Sevilla. Departamento de Química Física; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Junta de Andalucía; Universidad de Sevilla; Ministerio de Ciencia, Innovación y Universidades (MICINN). España; European Union (UE)The self-aggregation of four amphiphilic cationic calix[4]arenes, CALIX, in aqueous solutions was investigated in this work. The nature of the polar group present at the upper rim as well as the length of the hydrophobic tails attached to the lower rim was varied. All the calixarenes present two critical aggregation concentrations, CAC1 and CAC2. For [CALIX] < CAC1 only micelles are present, within the range CAC1 < [CALIX] < CAC2 micelles as well as vesicles are observed, and for [CALIX] > CAC2 micelles and a wide distribution of vesicles were found. Cell viability experiments show that calixarene micelles and several of the calixarene vesicles investigated could be used as biocompatible nanocarriers. On this basis, the study of the interactions between the cationic calixarene aggregates (micelles and vesicles) and calf thymus DNA, ctDNA, were done and the results indicated that most of them strongly interact with the polynucleotide, inverting its charge. Micelles totally compact the ctDNA, while vesicles only partially cause conformational changes in the nucleic acid. Therefore, the CALIX micelles show potential as vectors in gene therapy. The encapsulation of the antineoplastic drug doxorubicin into the calixarene aggregates was also investigated. A high encapsulation efficiency was found for micelles and, specially, for vesicles. However, DOX-loaded calixarene vesicles present low stability at 37 °C, which is a serious restriction in their use as nanocarriers for this drug. The release of DOX from the calixarene micelles shows that they could lengthen the half-life of free doxorubicin in the body and, as a result, lower amounts of drug could be used in the cancer treatments diminishing the important side effects of DOX.Artículo A complex and dynamic redox network regulates oxygen reduction at photosystem I in Arabidopsis(Oxford Academic Press, 2024-09-26) Hani, Umama; Naranjo Río-Miranda, Belén; Shimakawa, Ginga; Espinasse, Christophe; Vanacker, Helene; Setif, Pierre; Rintamaki, Eevi; Issakidis-Bourguet, Emmanuelle; Krieger-Liszkay, Anja; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Ecole Universitaire de Recherche de Sciences des Plantes de Paris-Saclay (SPS-GSR); Agence Nationale de la Recherche. France; Ministerio de Ciencia e Innovación (MICIN). España; Agencia Estatal de Investigación. EspañaThiol-dependent redox regulation of enzyme activities plays a central role in regulating photosynthesis. Besides the regulation of metabolic pathways, alternative electron transport is subjected to thiol-dependent regulation. We investigated the regulation of O2 reduction at photosystem I. The level of O2 reduction in leaves and isolated thylakoid membranes depends on the photoperiod in which plants are grown. We used a set of Arabidopsis (Arabidopsis thaliana) mutant plants affected in the stromal, membrane, and lumenal thiol network to study the redox protein partners involved in regulating O2 reduction. Light-dependent O2 reduction was determined in leaves and thylakoids of plants grown in short-day and long-day conditions using a spin-trapping electron paramagnetic resonance assay. In wild-type samples from short-day conditions, reactive oxygen species generation was double that of samples from long-day conditions, while this difference was abolished in several redoxin mutants. An in vitro reconstitution assay showed that thioredoxin m, NADPH-thioredoxin reductase C, and NADPH are required for high O2-reduction levels in thylakoids from plants grown in long-day conditions. Using isolated photosystem I, we also showed that reduction of a photosystem I protein is responsible for the increase in O2 reduction. Furthermore, differences in the membrane localization of m-type thioredoxins and 2-Cys peroxiredoxin were detected between thylakoids of short-day and long-day plants. Overall, we propose a model of redox regulation of O2 reduction according to the reduction power of the stroma and the ability of different thiol-containing proteins to form a network of redox interactions.