Modulation of Popocatépetl’s activity by regional and worldwide earthquakes
Volcanoes switching from quiescence to eruption shortly after catastrophic earthquakes have raised interest for volcanic triggering and the influence of earthquakes on volcanic activity. Its influence on already active systems and especially at open-vent volcanoes is more difficult to apprehend. A number of recent observations suggest an influence of tectonic earthquakes on Popocatépetl’s activity, the importance of which remains unknown. To further investigate this, we introduce an index, based on the near-field concept, identifying the earthquakes with the highest potential to promote volcanic activity (hereafter termed “significant earthquakes”). The time series of significant earthquakes is compared with the intensity of the volcanic activity, as characterized by the number and energy of volcano-tectonic earthquakes, the number of dome extrusions, the intensity of thermal and degassing fluxes, and ash production. Three main periods with contrasting activity stand out showing that Popocatépetl presents intense activity when significant tectonic earthquakes are frequent. Enhanced extrusion apparently follows significant earthquakes quickly with pulses of dome extrusion that peak after 1.3 ± 0.3 years. Conversely, extrusive activity vanishes when significant seismicity disappears, as during the period 2003–2011, which coincides with a 12-year-long significant seismicity gap. Hence, we propose that the 1994–2022 open-vent activity at Popocatépetl is in part modulated by the repetitive occurrence of significant earthquakes that periodically promote volcanic activity.
Boulesteix, Thomas; Legrand, Denis;Taquet, Noémie; Coppola, Diego; Laiolo, Marco; Valade, Sébastien; Massimetti, Francesco; Caballero-Jiménez, Gema; Campion, Robin.
Solid-Supported Tetrahydropyran-Based Hybrid Dipeptide Catalysts for Michael Addition of Aldehydes to Nitrostyrenes
The heterogenization of homogeneous catalysts onto a solid support is a step towards a more sustainable chemistry. The recovery and reuse of catalysts is extremely important from a practical, economic and environmental point of view. In this regards, we report a series of polymer-supported tetrahydropyran-based hybrid dipeptides that serve as active catalysts for the enantioselective Michael addition of aldehydes to β-nitrostyrenes. These supported catalysts have been designed considering the optimal anchor position and orientation between the catalyst and the solid support. Additionally, the influence of the linker length on the catalytic efficiency was studied. The catalysts allowed the transformation of a variety of substrates in 76–98% yield and with 94–97% enantiomeric excess. Detailed deactivation studies have provided important information, which allows to increase the useful life of these immobilized catalysts.
García-Monzón, Irma; Borges-González, Jorge; Martín, Tomás
Shortest Enantioselective Total Syntheses of (+)-Isolaurepinnacin and (+)-Neoisoprelaurefucin
The shortest enantioselective total syntheses of (+)-isolaurepinnacin and (+)-neoisoprelaurefucin have been accomplished. These syntheses were based on a common parallel synthetic strategy using Prins–Peterson cyclization in their core construction. In only one step, a seven-membered ring oxacycle with the correct cis-stereochemistry ring closure and the Δ4 position of the endocyclic double bond in (+)-isolaurepinnacin was obtained. This unsaturation was also necessary to accede to the bromodioxabicycle on (+)-neoisoprelaurefucin.
Sinka, Victoria; Cruz, Daniel A.; Martín, Víctor S.; Padrón, Juan I.
Chemistry of Hydrogen Peroxide Formation and Elimination in Mammalian Cells, and Its Role in Various Pathologies
Hydrogen peroxide (H2O2) is a compound involved in some mammalian reactions and processes. It modulates and signals the redox metabolism of cells by acting as a messenger together with hydrogen sulfide (H2S) and the nitric oxide radical (•NO), activating specific oxidations that determine the metabolic response. The reaction triggered determines cell survival or apoptosis, depending on which downstream metabolic pathways are activated. There are several ways to produce H2O2 in cells, and cellular systems tightly control its concentration. At the cellular level, the accumulation of hydrogen peroxide can trigger inflammation and even apoptosis, and when its concentration in the blood reaches toxic levels, it can lead to bioenergetic failure. This review summarizes existing research from a chemical perspective on the role of H2O2 in various enzymatic pathways and how this biochemistry leads to physiological or pathological responses.
Curieses Andrés, Celia María; Pérez de Lastra, José Manuel; Andrés Juan, Celia; Plou Gasca, Francisco José; Pérez-Lebeña, Eduardo.
Antimicrobial Activity of Cathelicidin-Derived Peptide from the Iberian Mole Talpa occidentalis
The immune systems of all vertebrates contain cathelicidins, a family of antimicrobial peptides. Cathelicidins are a type of innate immune effector that have a number of biological functions, including a well-known direct antibacterial action and immunomodulatory function. In search of new templates for antimicrobial peptide discovery, we have identified and characterized the cathelicidin of the small mammal Talpa occidentalis. We describe the heterogeneity of cathelicidin in the order Eulipotyphla in relation to the Iberian mole and predict its antibacterial activity using bioinformatics tools. In an effort to correlate these findings, we derived the putative active peptide and performed in vitro hemolysis and antimicrobial activity assays, confirming that Iberian mole cathelicidins are antimicrobial. Our results showed that the Iberian mole putative peptide, named To-KL37 (KLFGKVGNLLQKGWQKIKNIGRRIKDFFRNIRPMQEA) has antibacterial and antifungal activity. Understanding the antimicrobial defense of insectivores may help scientists prevent the spread of pathogens to humans. We hope that this study can also provide new, effective antibacterial peptides for future drug development.
Otazo-Pérez, Andrea; Asensio-Calavia, Patricia; González-Acosta, Sergio; Baca-González, Victoria; López, Manuel R; Morales-De la Nuez, Antonio; Pérez de la Lastra, José Manuel.
Cellular landscaping of cisplatin resistance in cervical cancer
Cervical cancer (CC) caused by human papillomavirus (HPV) is one of the largest causes of malignancies in women worldwide. Cisplatin is one of the widely used drugs for the treatment of CC is rendered ineffective owing to drug resistance. This review highlights the cause of resistance and the mechanism of cisplatin resistance cells in CC to develop therapeutic ventures and strategies that could be utilized to overcome the aforementioned issue. These strategies would include the application of nanocarries, miRNA, CRIPSR/Cas system, and chemotherapeutics in synergy with cisplatin to not only overcome the issues of drug resistance but also enhance its anti-cancer efficiency. Moreover, we have also discussed the signaling network of cisplatin resistance cells in CC that would provide insights to develop therapeutic target sites and inhibitors. Furthermore, we have discussed the role of CC metabolism on cisplatin resistance cells and the physical and biological factors affecting the tumor microenvironments.
Bhattacharjeea, Rahul; Deya, Tanima; Kumar, Lamha; Kar, Sulagna; Sarkar, Ritayan; Ghorai, Mimosa; Malik, Sumira; Kumar Jha, Niraj; Vellingiri, Balachandar; Kumar Kesari, Kavindra; Pérez de Lastra, José Manuel; Dey, Abhijit.
Differences in the levels of sulphites and pesticide residues in soils and wines and under organic and conventional production methods
The surface and output of organic agriculture is growing steadily in recent years, being generally seen as a healthier, safer and more sustainable alternative to conventional agriculture. Comparisons between organic and conventional products are nonetheless scarce in the literature, especially in the case of wine. The aim of this study was to compare sulphite content and pesticide residues in both soils and wines under organic and conventional production. Fourteen samples of organic and conventional wines and vineyard soils were collected in pairs for each of the seven wine-producing islands of the Canary Islands. A QuEChERS-based method was employed to detect 218 pesticides and 49 POPs. Sulphites were measured by potentiometric titration with a double electrode. On average, higher levels of sulphites were found in conventional wines. Similarly, conventional wines presented higher numbers and concentrations of pesticide residues both in soils and wines than their organic counterparts. The overall pesticide concentrations in our sample was 4.2 µg/kg. Conventional wines presented a considerably higher average concentration than organic wines (8.2 against 0.25 µg/kg). In turn, concentrations in conventional soils averaged 8.7 against 2.8 µg/kg in organic soils, a 68.19 % lower residue concentration. The analytes most commonly found were PCB 28, p,p′-DDE, tebuconazole and the metabolite 4,4′-dichlorobenzophenone in soils and mefenoxam, tebuconazole, fluopyram and boscalid in wines. No single wine exceeded the 10 % of the MRLs established by the European Union for wine grapes. However, the presence of low levels of pesticides in organic wines should be monitored.
Alonso-González, Pablo; Parga-Dans, Eva ; Acosta Dacal, Andrea Carolina; Zumbado Peña, Manuel; Pérez Luzardo, Octavio.
Aseismic Fault Slip During a Shallow Normal-Faulting Seismic Swarm Constrained Using a Physically Informed Geodetic Inversion Method
Improved imaging of the spatio-temporal growth of fault slip is crucial for understanding the driving mechanisms of earthquakes and faulting. This is especially critical to properly evaluate the evolution of seismic swarms and earthquake precursory phenomena. Fault slip inversion is an ill-posed problem and hence regularization is required to obtain stable and interpretable solutions. An analysis of compiled finite fault slip models shows that slip distributions can be approximated with a generic elliptical shape, particularly well for M ≤ 7.5 events. Therefore, we introduce a new physically informed regularization to constrain the spatial pattern of slip distribution. Our approach adapts a crack model derived from mechanical laboratory experiments and allows for complex slipping patterns by stacking multiple cracks. The new inversion method successfully recovered different simulated time-dependent patterns of slip propagation, that is, crack-like and pulse-like ruptures, directly using wrapped satellite radar interferometry (InSAR) phase observations. We find that the new method reduces model parameter space, and favors simpler interpretable spatio-temporal fault slip distributions. We apply the proposed method to the 2011 March–September normal-faulting seismic swarm at Hawthorne (Nevada, USA), by computing ENVISAT and RADARSAT-2 interferograms to estimate the spatio-temporal evolution of fault slip distribution. The results show that (a) aseismic slip might play a significant role during the initial stage and (b) this shallow seismic swarm had slip rates consistent with those of slow earthquake processes. The proposed method will be useful in retrieving time-dependent fault slip evolution and is expected to be widely applicable to studying fault mechanics, particularly in slow earthquakes.
Jiang, Yu; Samsonov, Sergey V.; González, Pablo J.
Global Tonga tsunami explained by a fast-moving atmospheric source
Volcanoes can produce tsunamis through earthquakes, caldera and flank collapses, pyroclastic flows, or underwater explosions1,2,3,4. These mechanisms rarely displace enough water to trigger transoceanic tsunamis. Violent volcanic explosions, however, can cause global tsunamis1,5 by triggering acoustic-gravity waves6,7,8 that excite the atmosphere-ocean interface. The colossal eruption of the Hunga Tonga-Hunga Ha'apai volcano and ensuing tsunami is the first global volcano-triggered tsunami recorded by modern, worldwide dense instrumentation, thus providing a unique opportunity to investigate the role of air-water coupling processes in tsunami generation and propagation. Here we use sea-level, atmospheric and satellite data from across the globe, along with numerical and analytical models, to demonstrate that this tsunami was driven by a constantly moving source in which the acoustic-gravity waves radiating from the eruption excite the ocean and transfer energy into it via resonance. A direct correlation between the tsunami and the acoustic-gravity waves’ arrival times confirms that these phenomena are closely linked. Our models also show that the unusually fast travel times and long duration of the tsunami, as well as its global reach, are consistent with an air-water coupled source. This coupling mechanism has clear hazard implications, since it leads to higher waves along landmasses that rise abruptly from long stretches of deep ocean waters.
Omira R., Ramalho R.S., Kim J., González P.J., Kadri U., Miranda J.M., Carrilho F., Baptista M.A.
Antimicrobial Resistance in the COVID-19 Landscape: Is There an Opportunity for Anti-Infective Antibodies and Antimicrobial Peptides?
Although COVID-19 has captured most of the public health attention, antimicrobial resistance (AMR) has not disappeared. To prevent the escape of resistant microorganisms in animals or environmental reservoirs a “one health approach” is desirable. In this context of COVID-19, AMR has probably been affected by the inappropriate or over-use of antibiotics. The increased use of antimicrobials and biocides for disinfection may have enhanced the prevalence of AMR. Antibiotics have been used empirically in patients with COVID-19 to avoid or prevent bacterial coinfection or superinfections. On the other hand, the measures to prevent the transmission of COVID-19 could have reduced the risk of the emergence of multidrug-resistant microorganisms. Since we do not currently have a sterilizing vaccine against SARS-CoV-2, the virus may still multiply in the organism and new mutations may occur. As a consequence, there is a risk of the appearance of new variants. Nature-derived anti-infective agents, such as antibodies and antimicrobial peptides (AMPs), are very promising in the fight against infectious diseases, because they are less likely to develop resistance, even though further investigation is still required.
Pérez de Lastra, José Manuel; Anand, Uttpal; González-Acosta, Sergio; López, Manuel R.; Dey, Abhijit; Bontempi, Elza; Morales-delaNuez, Antonio.