Biology subjects

Hernandez-Gonzalez, A.

Publications and source records attributed to Hernandez-Gonzalez, A..

4 recordsLinked to original sources

bioRxiv2026

Body condition as an indicator of long-term ecosystem change: evidence from common dolphins

As climate change continues to disrupt marine ecosystems, reliable body condition indices (BCIs) for sentinel megafauna species such as dolphins will become increasingly important tools for long-term ecosystem monitoring. We developed novel BCIs from routinely collected morphometric measurements and applied them to a 22-year dataset (1998-2019) of 597 stranded common dolphins (Delphinus delphis) from Northwest Spain. BCIs were calculated as residuals from Generalized Additive Models relating body length to girth and blubber thickness measurements, thereby controlling for body size effects. The indices were first validated against visually assessed nutritional status and then used to investigate long-term trends and potential environmental and trophic drivers of body condition. The girth-based BCI outperformed the blubber thickness-based index in predicting nutritional status. The indices differed in their sensitivity to confounding variables. Both indices revealed an increase in male body condition until 2009-2010 followed by a sustained decline through 2019, whereas no long-term trend was detected in females. By integrating data on climate variability (North Atlantic Oscillation), oceanographic conditions (upwelling intensity, sea surface temperature, chlorophyll-a), prey availability, and prey quality, we found evidence that changes in body condition was associated with climate- and oceanography-driven changes in prey communities and reductions in the quality of prey available to dolphins. Our findings suggest that body condition in common dolphins integrates signals across multiple components of marine ecosystems and can serve as a sensitive indicator of ecosystem change. Given growing reports of declining body condition in marine predators worldwide, the approach presented here provides a practical and transferable framework for long-term ecosystem monitoring using existing stranding network datasets.

ecology↗

bioRxiv2025

Inhibition of CaV1.4 channels by CaV3 channel antagonists ML218 and Z944

Among the three classes of voltage-gated Ca2+ channels (Cav1, Cav2, Cav3), Cav3 T-type channels are drug targets for disorders including epilepsy and pain. Antagonists such as Z944 and ML218 are highly selective for Cav3 compared to the Cav1.2 L-type channel but whether they have additional activity on other Cav1 subtypes is unknown. Here, we investigated the effects of Z944 and ML218 on the Cav1.4 channel which regulates neurotransmitter release from retinal photoreceptors. In HEK293T cells transfected with Cav1.4 and the auxiliary {beta}2x13 and 2{delta}-4 subunits, Z944 and ML218 inhibited Ca2+ currents with IC50 values of [~]30 {micro}M and 2 {micro}M, respectively. Structure-based modeling combined with functional studies revealed the importance of a cluster of methionine residues, particularly M1004, within the DHP binding site for the effects of ML218. Compared to mutation of a conserved threonine (T1007) that is required for DHP sensitivity of Cav1 channels, mutation of M1004 had a 10-fold greater impact in diminishing the potency of ML218. Cav1.2 was significantly less sensitive to ML218 inhibition (IC50[~] 37 {micro}M) than Cav1.4, which could not be attributed to a valine in place of M1004 in Cav1.2. We conclude that ML218 and Z944 are dual Cav1/Cav3 modulators of CaV1.4 and should be used with caution when dissecting the contributions of CaV3 channels in tissues where Cav1.4 is expressed.

biophysics↗

bioRxiv2023

Common evolutionary origins of the bacterial glycyl tRNA synthetaseand alanyl tRNA synthetase

Aminoacyl-tRNA synthetases (aaRSs) establish the genetic code. Each aaRS covalently links a given canonical amino acid to a cognate set of tRNA isoacceptors. Glycyl tRNA aminoacylation is unusual in that it is catalyzed by different aaRSs in different lineages of the Tree of Life. We have investigated the phylogenetic distribution and evolutionary history of bacterial glycyl tRNA synthetase (bacGlyRS). This enzyme is found in early diverging bacterial phyla such as Firmicutes, Acidobacteria, and Proteobacteria, but not in archaea or eukarya. We observe relationships between each of six domains of bacGlyRS and six domains of four different RNA-modifying proteins. Component domains of bacGlyRS show common ancestry with i) the catalytic domain of class II tRNA synthetases; ii) the HD domain of the bacterial RNase Y; iii) the body and tail domains of the archaeal CCA-adding enzyme; iv) the anti-codon binding domain of the arginyl tRNA synthetase; and v) a previously unrecognized domain that we call ATL (Ancient tRNA latch). The ATL domain is found only in bacGlyRS and in the universal alanyl tRNA synthetase (uniAlaRS). Further, the catalytic domain of bacGlyRS is more closely related to the catalytic domain of uniAlaRS than to any other aminoacyl tRNA synthetase. The combined data suggest that the ATL and catalytic domains of these two enzymes are ancestral to bacGlyRS and uniAlaRS, which emerged from common protein ancestors by bricolage, stepwise accumulation of protein domains, before the last universal common ancestor of life.

evolutionary biology↗

bioRxiv2021

Ancestral protein topologies draw the rooted bacterial tree of life

Aminoacyl tRNA synthetases (aaRSs) are among the proposed proteins present in the Last Universal Common Ancestor (LUCA). There are two types of glycyl tRNA synthetases (GlyRSs), from which the archaeal-eukaryal type is the one suggested to be present in LUCA. Here we solved the crystal structure of a complete bacterial glycyl tRNA synthetase (bacGlyRS) and show that indeed, bacGlyRS carries several structural signals that point it at the origin of all aaRSs. Furthermore, if bacGlyRS is ancestral, it should help to build a reliable Tree of Life (ToL). Given the modular nature of protein evolution, we used only two sub-domain segments with duplicated ancestral topologies, no detected orthologs and an assumed limited horizontal gene transfer (HGT). These motifs correspond to the non-specific RNA binding regions of contemporary bacGlyRS, archaeal CCA-adding enzyme (arch-CCAadd), and eukaryotic rRNA processing enzyme (euk-rRNA). The calculated, rooted bacterial ToL agrees with several phyla relationships unaccounted by the available trees.

evolutionary biology↗