Shallow magmatic intrusion evolution below La Palma before and during the 2021 eruption

La Palma, Canary Islands, underwent volcanic unrest which culminated in its largest historical eruption. We study this unrest along 2021 using Interferometric Synthetic Aperture Radar (InSAR) and a new improved interpretation methodology, comparing achieved results with the crustal structure. We reproduce the final phase of La Palma volcanic unrest, highligthing a shallow magma accumulation which begins about 3.5 months before the eruption in a crustal volume charactherized by low density and fractured rocks. Our modeling, together with our improved pictures of the crustal structure, allows us to explain the location and characteristics of the eruption and to detect failed eruption paths. These can be used to explain post-eruptive phenomena and hazards to the local population, such as detected gases anomalies in La Bombilla and Puerto Naos. Our results have implications for understanding volcanic activity in the Canaries and volcano monitoring elsewhere, helping to support decision-making and providing significant insights into urban and infrastructure planning in volcanic areas.

Modeling the two- and three-dimensional displacement field in Lorca, Spain, subsidence and the global implications

Land subsidence associated with overexploitation of aquifers is a hazard that commonly affects large areas worldwide. The Lorca area, located in southeast Spain, has undergone one of the highest subsidence rates in Europe as a direct consequence of long-term aquifer exploitation. Previous studies carried out on the region assumed that the ground deformation retrieved from satellite radar interferometry corresponds only to vertical displacement. Here we report, for the first time, the two- and three-dimensional displacement field over the study area using synthetic aperture radar (SAR) data from Sentinel-1A images and Global Navigation Satellite System (GNSS) observations. By modeling this displacement, we provide new insights on the spatial and temporal evolution of the subsidence processes and on the main governing mechanisms. Additionally, we also demonstrate the importance of knowing both the vertical and horizontal components of the displacement to properly characterize similar hazards. Based on these results, we propose some general guidelines for the sustainable management and monitoring of land subsidence related to anthropogenic activities.

Kinetic properties and inhibition of the dimeric dUTPase-dUDPase from Leishmania major

Kinetic properties of the dimeric enzyme dUTPase from Leishmania major were studied using a continuous spectrophotometric method. dUTP was the natural substrate and dUMP and PPi the products of the hydrolysis. The trypanosomatid enzyme exhibited a low K(m) value for dUTP (2.11 microM), a k(cat) of 49 s(-1), strict Michaelis-Menten kinetics and is a potent catalyst of dUDP hydrolysis, whereas in other dUTPases described, this compound acts as a competitive inhibitor. Discrimination is achieved for the base and sugar moiety showing specificity constants for different dNTPs similar to those of bacterial, viral, and human enzymes. In the alkaline range, the K(m) for dUTP increases with the dissociation of ionizable groups showing pK(a) values of 8.8, identified as the uracil moiety of dUTP and 10, whereas in the acidic range, K(m) is regulated by an enzyme residue exhibiting a pK(a) of 7.1. Activity is strongly inhibited by the nucleoside triphosphate analog alpha-beta-imido-dUTP, indicating that the enzyme can bind triphosphate analogs. The existence of specific inhibition and the apparent structural and kinetic differences (reflected in different binding strength of dNTPs) with other eukaryotic dUTPases suggest that the present enzyme might be exploited as a target for new drugs against leishmaniasis.

Crystallization and preliminary X-ray diffraction studies of the epsilonzeta addiction system encoded by Streptococcus pyogenes plasmid pSM19035

The proteins encoded by the Streptococcus pyogenes broad-host range and low copy-number plasmid pSM19035 form a toxin-antitoxin module that secures stable maintenance by causing the death of plasmid-free segregants. The epsilonzeta protein complex was crystallized in four different forms at pH 5.0 and pH 7.0 using the vapour-diffusion method with PEG 3350 and ethylene glycol as precipitants. Three of the crystal forms were obtained in the same droplet under identical conditions at pH 5.0. One form belongs to the enantiomorphic space groups P4(3)2(1)2 or P4(1)2(1)2. For the other two, the X-ray reflection conditions match those of space group P2(1)2(1)2(1), one representing a superlattice of the other. A crystal form growing at pH 7.0 also belongs to space group P2(1)2(1)2(1), but there is no indication of a structural relationship to the other orthorhombic forms. Initially, the crystals diffracted to 2.9 A resolution and diffracted to 1.95 A after soaking at pH 7.0. A preparation of selenomethionyl epsilonzeta protein complex yielded single crystals suitable for X-ray diffraction experiments using synchrotron sources.

Functional analysis of the terminase large subunit, G2P, of Bacillus subtilis bacteriophage SPP1

The terminase of bacteriophage SPP1, constituted by a large (G2P) and a small (G1P) subunit, is essential for the initiation of DNA packaging. A hexa-histidine G2P (H6-G2P), which is functional in vivo, possesses endonuclease, ATPase, and double-stranded DNA binding activities. H6-G2P introduces a cut with preference at the 5'-RCGG downward arrowCW-3' sequence. Distamycin A, which is a minor groove binder that mimics the architectural structure generated by G1P at pac, enhances the specific cut at both bona fide 5'-CTATTGCGG downward arrowC-3' sequences within pacC of SPP1 and SF6 phages. H6-G2P hydrolyzes rATP or dATP to the corresponding rADP or dADP and P(i). H6-G2P interacts with two discrete G1P domains (I and II). Full-length G1P and G1PDeltaN62 (lacking domain I) stimulate 3.5- and 1.9-fold, respectively, the ATPase activity of H6-G2P. The results presented suggest that a DNA structure, artificially promoted by distamycin A or facilitated by the assembly of G1P at pacL and/or pacR, stimulates H6-G2P cleavage at both target sites within pacC. In the presence of two G1P decamers per H6-G2P monomer, the H6-G2P endonuclease is repressed, and the ATPase activity stimulated. Based on these results, we propose a model that can account for the role of terminase in headful packaging.