Structural diversity using amino acid “Customizable Units”: conversion of hydroxyproline (Hyp) into nitrogen heterocycles

The ability of amino acid “customizable units” to generate structural diversity is illustrated by the conversion of 4-hydroxyproline (Hyp) units into a variety of nitrogen heterocycles. After a frst common step, where the unit underwent a one-pot decarboxylation–alkylation reaction to aford 2-alkylpyrrolidines with high stereoselectivity, a divergent step was carried out. Thus, the deprotected 4-hydroxy group was used either to initiate a radical scission that aforded aliphatic β-amino aldehydes, or to carry out an elimination reaction, to give 2-alkyl-2,5-dihydro-1H-pyrroles. In the frst case, the amines underwent a tandem reductive amination–cyclization to aford β-amino-δ-lactams, an efcient rigidifying unit in peptides. Diferent lactam N-substituents, such as alkylamines, peptides, and alkenyl chains suitable for olefn metathesis were introduced this way. In the second case, the pyrrole derivatives were efciently converted into alkaloid and iminosugar derivatives in good global yields and with excellent stereoselectivity.

Hernández, Dácil; Porras, Marina; Boto, Alicia.

Amino Acids: 1-12 (2022)
DOIDigital.CSIC

Volcano-tectonic control of Cumbre Vieja

The 2021 Cumbre Vieja volcano eruption started on 19 September 2021 and ended after 85 days and 8 hours, becoming La Palma’s longest and most voluminous (more than 200 million m3) eruption in historical times. Because of the good monitoring effort, this eruption will allow the testing of a wide range of scientific ideas, from the importance of a possible 436-year-long supercycle of duration-decreasing eruptions to using the geophysical observations to understand how magma is stored and migrates within a vertically extended upper mantle and crustal magmatic system. These types of magmatic and volcanological information will transform volcano eruption hazard assessment and long-term planning. Moreover, a key research question remains as to why this eruption did not create a catastrophic volcano flank collapse as perhaps expected. The answer may be tied to its distinct volcano-tectonic features and, in particular, an unexpected fissure system that opened during the eruption’s last phase

González, Pablo J.

Science
DOIDigital.CSIC

Subduction earthquakes controlled by incoming plate geometry: The 2020 M > 7.5 Shumagin, Alaska, earthquake doublet

In 2020, an earthquake doublet, a M7.8 on July 22nd and a M7.6 on October 19th, struck the Alaska-Aleutian subduction zone beneath the Shumagin Islands. This is the first documented earthquake doublet involving a megathrust event and a strike-slip event. The first event partially ruptured a seismic gap, which has not hosted large earthquakes since 1917, and the second event was unusual as it broke a trench-perpendicular fault within the incoming oceanic slab. We used an improved Bayesian geodetic inversion method to estimate the fault slip distributions of the major earthquakes using Interferometric Synthetic Aperture Radar (InSAR) wrapped phase and Global Navigation Satellite Systems (GNSS) offsets data. The geodetic inversions reveal that the Shumagin seismic gap is multi-segmented, and the M7.8 earthquake ruptured the eastern segment from 14 km down to 44 km depth. The coseismic slip occurred along a more steeply, 26◦ dipping segment, and was bounded up-dip by a bend of the megathrust interface to a shallower 8◦ dip angle connecting to the trench. The model for the M7.6 event tightly constrained the rupture depth extent to 19-39 km, within the depth range of the M7.8 coseismic rupture area. We find that the M7.6 event ruptured the incoming slab across its full seismogenic thickness, potentially reactivating subducted Kula-Resurrection seafloor-spreading ridge structures. Coulomb stress transfer models suggest that coseismic and/or postseismic slip of the M7.8 event could have triggered the M7.6 event. We conclude that the segmented megathrust structure and the location of intraslab fault structures limited the rupture dimensions of the M7.8 event and are responsible for the segmentation of the Shumagin seismic gap. Our study suggests that the western and shallower up-dip segments of the seismic gap did not fail and remain potential seismic and tsunami hazard sources. The unusual earthquake doublet provides a unique opportunity to improve our understanding of the role of the subducting lithosphere structure in the segmentation of subduction zones.

Yu, Jiang; González Méndez, Pablo José; Bürgmann, Roland.

Earth and Planetary Science Letters 584, 117447: 1-13 (2022)
DOIDigital.CSIC

Cancer chemotherapy and beyond: Current status, drug candidates, associated risks and progress in targeted therapeutics

Cancer is an abnormal state of cells where they undergo uncontrolled proliferation and produce aggressive malignancies that cause millions of deaths every year. With the new understanding of the molecular mechanism(s) of disease progression, our knowledge about the disease is snowballing, leading to the evolution of many new therapeutic regimes and their successive trials. In the past few decades, various combinations of therapies have been proposed and are presently employed in the treatment of diverse cancers. Targeted drug therapy, immunotherapy, and personalized medicines are now largely being employed, which were not common a few years back. The field of cancer discoveries and therapeutics are evolving fast as cancer type-specific biomarkers are progressively being identified and several types of cancers are nowadays undergoing systematic therapies, extending patients’ disease-free survival thereafter. Although growing evidence shows that a systematic and targeted approach could be the future of cancer medicine, chemotherapy remains a largely opted therapeutic option despite its known side effects on the patient’s physical and psychological health. Chemotherapeutic agents/pharmaceuticals served a great purpose over the past few decades and have remained the frontline choice for advanced-stage malignancies where surgery and/or radiation therapy cannot be prescribed due to specific reasons. The present report succinctly reviews the existing and contemporary advancements in chemotherapy and assesses the status of the enrolled drugs/pharmaceuticals; it also comprehensively discusses the emerging role of specific/targeted therapeutic strategies that are presently being employed to achieve better clinical success/survival rate in cancer patients.

Anand, Uttpal; Dey, Abhijit; Chandel, Arvind K. Singh; Sanyal, Rupa; Mishra, Amarnath; Pandey, Devendra Kumar; De Falco, Valentina; Upadhyay, Arun; Kandimalla, Ramesh; Chaudhary, Anupama; Dhanjal, Jaspreet Kaur; Dewanjee, Saikat; Vallamkondu, Jayalakshmi; Pérez De La Lastra, José M.

Genes & Diseases : 1-35 (2022)
DOIDigital.CSIC

New Biostimulants Screening Method for Crop Seedlings under Water Deficit Stress

Biostimulants can be used in many crops growing under water deficit conditions at the seedling stage. This study used tomato, Solanum lycopersicum L., seedlings growing in commercial 150-cell trays as an experimental setup to reproduce mild drought stress effects. The method showed significant reductions in seedling growth and RGR (25%) after a seven-day experiment. Gas exchange parameters (Pn, Gs and E) had significantly lower values (30–50%) than the control seedlings. Stress-related metabolite, ABA, exhibited a significant accumulation in the tomato seedlings (24 h), consistent with SINCED2 gene expression. Proline levels were twice as high in the water-deficit treated seedlings, remaining at this level until the end of the experiment. However, total carbohydrates were significantly lower in water-deficit treated seedlings. Qualitative and quantitative analysis suggested that using the variable ‘seedling biomass accumulation’ could simplify the methodology. Twelve different biostimulants were assayed, implementing this simplification, and all of them showed higher biomass accumulation in the treated seedlings than in the non-treated ones under water deficit. Among them, putrescine, spermine and spermidine were the most effective. The method is adjustable to different biostimulant volumes (1, 3 and 5 mL; 1 mM BABA), with no significant differences between the treatments.

Jiménez-Arias, David; Morales-Sierra, Sarai; Borges, Andrés A.; Herrera, Antonio J.; Luis, Juan C.

Agronomy 12(3), 728: 1-15 (2022)
DOIDigital.CSIC

A new cavernicolous assassin bug from the Canary Islands (Hemiptera: Reduviidae: Emesinae: Collartidini)

The Canary Archipelago is home to two species of obligately cavernicolous assassin bugs of the genus Collartida Villiers, 1949 (Hemiptera: Heteroptera: Reduviidae: Emesinae: Collartidini). These species are highly adapted for cave life, being blind and wingless. In the present study, we describe a new species of the genus, C. phantasma sp. nov. from the Federica mine in Gran Canaria. C. phantasma sp. nov. differs from the other two Collartida species found in the Canary Archipelago in that the male is fully winged, the female is wingless, and both sexes have well-developed eyes. We provide information regarding the new species’ habitat, its taxonomic affinities, and its ability to fly.

Davranoglou, Leonidas-Romanos; Baňař, Petr; Suárez, Daniel; Martín, Sonia; Naranjo, Manuel.

Zootaxa 5115(3): 342–360 (2022)
DOIDigital.CSIC

Mapping stressed wheat plants by soil aluminum efect using C‑band SAR images: implications for plant growth and grain quality

Under toxic aluminum (Al) levels in the soil, wheat (Triticum aestivum L.) sufers stress and plant growth is afected. A method for diagnosis of plants is proposed that includes the following as a strategy: to analyze total Al in the soil, employ satellite radar imagery and calculate a vegetation index. The objective of this research, conducted at the feld scale, was to explore how radar backscattering coefcients from a winter wheat canopy, combined with the normalized diference vegetation index (NDVI) and geographic information system (GIS) technology, can be used as a mapping tool for the variability of Al-stressed canopies. As a result, an analysis of covariance showed signifcant diferences, and the lowest plant height was obtained at a high level of soil Al, as well as the minimum grain weight and magnesium content. It was found that a simple model could be used to estimate plant height from the backscattering coefcient of vertical transmit-vertical receive polarization (σ°VV), with a strong correlation (r−0.84). In turn, a third-order polynomial regression model (R20.70) was proposed to estimate the NDVI from σ°VV. This model provided a good estimate of the NDVI at the stem elongation stage of growth (50 days after sowing). Detected NDVI patterns were associated with variation in canopy stress depending on polarimetric information, which, in turn, was related to soil Al levels. Thus, the maps derived from the model can monitor spatial variability, where NDVI values<0.68 indicate stressed areas. This study provides guidance for in-season stress spatial variability caused by Al.

Hernández, Mercedes; Borges, Andrés A.; Francisco‑Bethencourt, Desiderio.

Precision Agriculture 1-21 (2022)
DOIDigital.CSIC

Cyclolauranes as plausible chemical scaffold against Naegleria fowleri

Primary amoebic meningoencephalitis (PAM) is a central nervous system (CNS) disease caused by Naegleria fowleri that mainly affects children and young adults with fatal consequences in most of the cases. Treatment protocols are based on the combination of different antimicrobial agents, nonetheless there is the need to develop new anti-Naegleria compounds with low toxicity and full effects compared to the currently used drug combination. The marine environment is a well-established source of bioactive natural products. In this work, we have focused on the structure of Laurencia cyclolaurane-type sesquiterpenes as potential chemical model against Naegleria species. The effects of debromolaurinterol (1) to induce PCD/apoptosis-like events in Naegleria fowleri have been evaluated, revealing that this compound induced reduction of ATP production showing a decrease of 99.98% in treated parasite cells. A SAR analysis have been supported with molecular modeling and analysis of the in silico ADME/Tox properties of the Laurencia sesquiterpenes debromolaurinterol (1), laurinterol (2) and allolaurinterol (3), which reinforce cyclolaurane metabolites as plausible molecular models to develop PAM treatments.

Arberas-Jiménez, Íñigo; García-Davis, Sara; Rizo-Liendo, Aitor; Sifaoui, Inés; Quintana Morales, Ezequiel; Piñero, José E.; Lorenzo-Morales, Jacob; Díaz-Marreno, Ana R.; Fernández, José J.

Biomedicine and Pharmacotherapy 149, 112816: 1-11 (2022)
DOIDigital.CSIC

Applying Biostimulants to Combat Water Deficit in Crop Plants: Research and Debate

Climate change has increased the severity of drought episodes by further reducing precipitation in vulnerable zones. Drought induces a substantial decrease in agricultural water, reducing crop yields. Consequently, addressing water consumption can increase farmers’ profits. This work describes lab-to-field research in Zea mays, using two biostimulants: glycine betaine (GB) and Lpyroglutamic acid (PG). The biostimulant optimal dosages were selected using a hydroponic system with 20% polyethylene glycol and nursery experiments under water-deficit irrigation. The established dosages were evaluated in field trials in which irrigation was reduced by 20%. Laboratory biostimulant optimisation showed in stressed treated seedlings (GB 0.1 mM; PG 1 mM) an increased dry weight, relative growth rate and water use efficiency, reducing seedling growth loss between 65 and 85%, respectively. Field trials using a GB-optimised dosage showed an increase in plants’ growth, grain yield and flour Ca content. In addition, grain flour carbohydrate content and protein remained similar to control well-watered plants. Finally, the economic aspects of biostimulant treatments, water consumption, water sources (ground vs. desalinated) and grain biomass were addressed. Overall, GB treatment demonstrated to be a valuable tool to reduce water consumption and improve farmers’ earnings.

Jiménez-Arias, David; Hernándiz, Alba E.; Morales-Sierra, Sarai; García-García, Ana L.; García-Machado, Francisco J.; Luis, Juan C.; Borges, Andrés A.

Agronomy 12(3), 571: 1-12 (2022)
DOIDigital.CSIC

Exploring the Agricultural Reutilisation of Desalination Reject Brine from Reverse Osmosis Technology

Among its other effects, climate change is driving humanity into water scarcity, especially in highly populated areas such as the Mediterranean. One of the best options to solve this problem is seawater desalination, but it has its environmental, social and economic impacts. The brine reject effluent from the process can be used as a rich mineral source for hydroponic culture. Indeed, stability in its composition was shown here during a one-year study. A compilation of analyses from desalination facilities located worldwide also demonstrates how reutilisation of this liquid waste can provide an opportunity to build a circular economy based on brine management. Potential profitable crops and an economic study of its implementation are discussed. Correct brine management channelled into an agricultural context can be an excellent way to improve the public and ecological reputation of desalination. It can also yield extra income beyond the fresh water yield from the proposed system.

Jiménez-Arias, David; Morales Sierra, Sarai; García-Machado, Francisco J.; García-García, Ana L.; Borges, Andrés A. ; Luis, Juan C.

Desalination 529, 115644: 1-24 (2022)
DOIDigital.CSIC