TBS-pyrrole as an “universal” reference to quantify artemisinin and structurally-diverse natural products in plants extracts by NMR
The commercial production of artemisinin and other valuable bioactive natural products depends on their plant sources, which may provide variable amounts of the compound depending on plant variety, the period of the year, abiotic stress and other factors. Therefore, it requires a method for large-scale, low-cost natural product quantification. The standard HPLC and UHPLC methods are accurate but the analysis are costly and require different optimization for structurally-diverse products. An alternative method using NMR with TBS-pyrrole as a novel “universal” reference affords a simple, fast method to quantify many different products. The method is shown with antimalarial artemisinin, whose yield using conventional and novel extraction procedures was determined by standard UHPLC-MS procedures and by our NMR protocol, with similar quantification results. The novel reference compound does not interfere with artemisinin or extract signals, only needs a small amount of the extract, is accurate and operationally simple, and a large volume of samples can be processed in little time. Moreover, bioactive terpenes, steroids, alkaloids, aromatic compounds, and quinones, among others, were quantified in a model vegetal extract with this “universal” reference with excellent accuracy.
García-García, Ana L.; Hernández, Dácil C; Santana-Mayor, Álvaro; Jiménez-Arias, David; Boto, Alicia.
Biostimulant activity of Galaxaura rugosa seaweed extracts against water deficit stress in tomato seedlings involves activation of ABA signaling
Water scarcity is a serious constraint for agriculture, and global warming and climate change can exacerbate it in many areas. Therefore, sustainable approaches must be implemented to deal with current and future water scarcity scenarios. Genetic and chemical approaches are being applied to manage this limitation and maintain crop yields. In particular, biostimulants obtained from natural sources such as marine algae are promising aids for coping with water deficit stress in agriculture. Here we present a bioprospection study of extracts of the macroalgae Bonnemaisonia hamifera, Galaxaura rugosa, Dasycladus vermicularis, Ulva clathrata, Cystoseira foeniculacea, Cystoseira humilis, Lobophora dagamae, Colpomenia sinuosa and Halopteris scoparia from the north coast of Tenerife, in the Canary Islands. The aqueous extracts of Bonnemaisonia hamifera, Galaxaura rugosa, Dasycladus vermicularis and Cystoseira humilis show biostimulant activity against water deficit stress in tomato seedlings under controlled conditions, providing higher tolerance than the mock-treated control. The Galaxaura rugosa extract showed the highest biostimulant activity against water deficit stress. We demonstrate that this positive effect involves the activation of the abscisic acid (ABA) pathway in Arabidopsis thaliana (arabidopsis) and Solanum lycopersicum (tomato). Application of G. rugosa extract to the root system by drenching tomato seedlings subjected to water deficit leads to improved CO2 assimilation and water use efficiency (WUEp), compared to mock-treated plants. These results highlight a new potential seaweed source of substances with osmoprotectant properties, useful for biostimulant development. Future studies may provide further insight into which components of the seaweed extract induce activation of the ABA pathway.
Morales-Sierra, Sarai; Cristo Luis, Juan; Jiménez-Arias, David; Rancel-Rodríguez, Nereida M.; Coego, Alberto; Rodriguez, Pedro L.; Cueto, Mercedes; Borges, Andrés A.
Bubble-enhanced basanite–tephrite mixing in the early stages of the Cumbre Vieja 2021 eruption, La Palma, Canary Islands
Syneruptive magma mixing is widespread in volcanic eruptions, affecting explosivity and composition of products, but its evidence in basaltic systems is usually cryptic. Here we report direct evidence of mixing between basanitic and tephritic magmas in the first days of the 2021 Tajogaite eruption of Cumbre Vieja, La Palma. Groundmass glass in tephritic tephra from the fifth day of the eruption is locally inhomogeneous, showing micron-scale filamentary structures of Si-poor and Fe-, Mg-rich melt, forming complex filaments attached to bubbles. Their compositional distribution attests the presence of primitive basanitic magma, with compositions similar to late-erupted melts, interacting with an evolved tephritic melt during the first week of the event. From filament morphology, we suggest their generation by dragging and folding of basanitic melt during bubble migration through melt interfaces. Semi-quantitative diffusion modelling indicates that the filamentary structures are short-lived, dissipating in timescales of tens of seconds. In combination with thermobarometric constraints, we suggest a mixing onset by sub-Moho remobilization of a tephritic reservoir by basanite input, followed by turbulent ascent of a mingled magma. In the shallow conduit or lava fountain, bubble nucleation and migration triggered further mingling of the distinct melt-phases. This phenomenon might have enhanced the explosive behaviour of the eruption in such period, where violent strombolian explosions were common.
González-García, Diego; Boulesteix, Thomas; Klügel, Andreas; Holtz, François.
Diastereoselective Halogenation Reactions
A review of the last 10 years of diastereoselective halogenation methods is presented. They have been divided by reactions into alkenes, alkynes, and heterocycles. In many of the cases, the use of transition metals is described. In all of them, the mechanistic approach proposed by the authors and justifying the obtained diastereoselection is discussed. A miscellaneous section is also included in which allylic fluorinations, double bond isomerizations, ring expansion, and ring-opening halogenations are discussed.
Cruz, Daniel A.; Sinka, Victoria; Padrón, Juan I.
The natural wine phenomenon and the promise of sustainability: Institutionalization or radicalization?
Natural wine is produced with organic grapes without the use of additives. As a social phenomenon, it comprises rural winemakers and urban consumers interconnected by a vibrant global community of distributors, bloggers, experts, and associations. Despite its continuous growth since the early 2000s, the movement has sparked global public interest since the French recognition of the vin méthode nature certification in 2020. Here we delineate the evolution of the natural wine phenomenon from its origins to its current situation. It will be argued that rather than a social movement or an alternative food network, natural wine can be better understood as a food phenomenon exhibiting a sustainable alternative mode of production and consumption that unites a loose coalition of diverse actors. In exploring the constant tensions involved in the ongoing redefinition of natural wine by social actors, we will analyze their different understandings of locality, naturalness, and ethical food production.
Alonso-González, Pablo; Parga-Dans, Eva.
Identification of potential invasive alien species in Spain through horizon scanning
Invasive alien species have widespread impacts on native biodiversity and ecosystem services. Since the number of introductions worldwide is continuously rising, it is essential to prevent the entry, establishment and spread of new alien species through a systematic examination of future potential threats. Applying a three-step horizon scanning consensus method, we evaluated non-established alien species that could potentially arrive, establish and cause major ecological impact in Spain within the next 10 years. Overall, we identified 47 species with a very high risk (e.g. Oreochromis niloticus, Popillia japonica, Hemidactylus frenatus, Crassula helmsii or Halophila stipulacea), 61 with high risk, 93 with moderate risk, and 732 species with low risk. Many of the species categorized as very high or high risk to Spanish biodiversity are either already present in Europe and neighbouring countries or have a long invasive history elsewhere. This study provides an updated list of potential invasive alien species useful for prioritizing efforts and resources against their introduction. Compared to previous horizon scanning exercises in Spain, the current study screens potential invaders from a wider range of terrestrial, freshwater, and marine organisms, and can serve as a basis for more comprehensive risk analyses to improve management and increase the efficiency of the early warning and rapid response framework for invasive alien species. We also stress the usefulness of measuring agreement and consistency as two different properties of the reliability of expert scores, in order to more easily elaborate consensus ranked lists of potential invasive alien species.
Cano-Barbacil, Carlos; Carrete, Martina; Castro-Díez, Pilar; Delibes-Mateos, Miguel; Jaques, Josep A.; López-Darias, Marta; Nogales, Manuel; Pino, Joan; Ros, Macarena; Traveset, Anna; Turon, Xavier; Vilà, Montserrat; Altamirano, María; Álvarez, Inés; Arias, Andrés; Boix, Dani; Cabido, Carlos; Cacabelos, Eva; Cobo, Fernando; Cruz, Joaquín; Cuesta, José A.; Dáder, Beatriz; Estal, Pedro del; Gallardo, Belinda; Gómez Laporta, Miguel; González-Moreno, Pablo; Carlos Hernández, José; Jiménez-Alfaro, Borja; Lázaro Lobo, Adrián; Leza, Mar; Montserrat, Marta; Oliva-Paterna, Francisco J.; Piñeiro, Laura; Ponce, Carlos; Pons, Pere; Rotchés-Ribalta, Roser; Roura-Pascual, Núria; Sánchez, Marta; Trillo, Alejandro; Viñuela, Elisa; García-Berthou, Emili.
El Hierro Island Volcanological Science: An Overview
El Hierro Island, the youngest of the Canary Islands, and its latest eruption in 2011–2012 have been a playground of fruitful decade-long studies. In this book, we summarize and provide future venues of action to solve outstanding questions. The topics cover geological studies of Holocene volcanism so it informs past, present and future activity. Its active magmatic system from a petrological and geophysical lens. How monitoring of volcanic activity can be optimized and how to read the data streams in a meaningful way. The marine environmental effects of a submarine eruption are covered in detail, as well as how the society could be properly engage to reduce the risks associated to it, and appreciate and benefit from it. So, in each chapter the reader should find inspiration and future challenges waiting to be solved. Remaining puzzles pieces about how volcanism works and how it affects its environment. An effort to provide food for thoughts of future Canary Islands volcanological research, and in particular El Hierro.
González, Pablo J.
Lewis Acid-Catalyzed Carbonyl-Ene Reaction: Interplay between Aromaticity, Synchronicity, and Pauli Repulsion
The physical factors governing the catalysis in Lewis acid-promoted carbonyl-ene reactions have been explored in detail quantum chemically. It is found that the binding of a Lewis acid to the carbonyl group directly involved in the transformation greatly accelerates the reaction by decreasing the corresponding activation barrier up to 25 kcal/mol. The Lewis acid makes the process much more asynchronous and the corresponding transition state less in-plane aromatic. The remarkable acceleration induced by the catalyst is ascribed, by means of the activation strain model and the energy decomposition analysis methods, mainly to a significant reduction of the Pauli repulsion between the key occupied π-molecular orbitals of the reactants and not to the widely accepted stabilization of the LUMO of the enophile.
Rodríguez, Humberto A.; Cruz, Daniel A.; Padrón, Juan I.; Fernández, Israel.
Conversion of Hydroxyproline “Doubly Customizable Units” to Hexahydropyrimidines: Access to Conformationally Constrained Peptides
The efficient transformation of hydroxyproline “doubly customizable units” into rigid hexahydropyrimidine units takes place in good global yields and generates compounds of pharmaceutical interest. In particular, the process can readily provide access to peptidomimetics and peptides with reversed sequences or with valuable turns.
Hernández, Dácil; Porras, Marina; Boto, Alicia.
Volcanic ash deposition as a selection mechanism towards woodiness
The high proportion of woody plant species on oceanic islands has hitherto been explained mainly by gradual adaptation to climatic conditions. Here, we present a novel hypothesis that such woodiness is adaptative to volcanic ash (tephra) deposition. Oceanic islands are subject to frequent eruptions with substantial and widespread ash deposition on evolutionary time scales. We postulate that this selects for woodiness through an increased ability to avoid burial of plant organs by ash, and to re-emerge above the new land surface. We sense-checked using observations of plant occurrences and distributions on La Palma (Canary Islands) in April 2022, 4 months after the end of the eruptions of the Tajogaite volcano (Cumbre Vieja ridge). In contrast to herbs and grasses, most woody plants persisted and were already in full flower in areas with 10+ cm ash deposition. Remarkably, these persisting woody plants were almost exclusively endemics.
Beierkuhnlein, Carl; Nogales, Manuel; Field, Richard; Vetaas, Ole R.; Walentowitz, Anna; Weiser, Frank; Stahlmann, Reinhold; Guerrero-Campos, María; Jentsch, Anke; Medina, Félix M.; Chiarucci, Alessandro.