Biology subjects

Vera, A.

Publications and source records attributed to Vera, A..

4 recordsLinked to original sources

bioRxiv2025

Integrating flowering and stress responses in Arabidopsis through KH-domain genes

Plant reproductive success largely relies on flowering under favorable conditions. However, stress factors have forced plants to acquire adaptive strategies to coordinate floral timing and stress responses through key genetic elements. RNA-binding proteins with K-homology (KH) domains are emerging as versatile regulators of an increasing number of plant developmental processes, including flowering and stress acclimation. In Arabidopsis thaliana, FLK and HOS5 encode multifaceted KH-domain proteins associated with transcription and cotranscriptional operations. FLK facilitates floral transition by repressing FLC, the central flowering inhibitor, while both KH-genes have been involved in abiotic stress and defense against pathogens. Our genetic and molecular data identify HOS5 as a novel flowering regulator that, together with FLK, represses FLC. Our transcriptomics results reveal that, in addition, FLK and HOS5 cooperatively repress numerous stress-responsive genes. Consistent with this, flk hos5 double mutant plants exhibit elevated levels of stress-induced gene activities and enhanced resistance to abiotic stress and pathogenic fungi. The coordinated repression of FLC and stress-induced genes by FLK and HOS5 suggests that these KH proteins are part of a cotranscriptional regulatory hub key for orchestrating flowering time and environmental adaptation responses.

plant biology↗

bioRxiv2024

A comparison among EL-FAME, PLFA, and quantitative PCR methods to detect changes in the abundance of soil bacteria and fungi

EL-FAME (ester-linked fatty acid methyl ester), PLFA (phospholipid fatty acid) and qPCR (quantitative PCR) of ribosomal genes are three of the most common methods used to quantify soil microbial communities. The reliability of these three methods has not been simultaneously compared in situations of rapid changes in soil microbial abundances. For this purpose, we (i) incubated badland, cropland, and forest soils with nutrients or antibiotics for 2, 7, 14, and 28 days, (ii) quantified total, bacterial, and fungal abundances through EL-FAME, PLFA, and qPCR methods, and (iii) measured soil basal respiration. The general dynamic patterns of the three soil microbial fractions in response to soil addition of nutrients and antibiotics were captured by the three methods, which led to strong and positive associations between the abundances of total microorganisms, bacteria, and fungi measured by the three techniques. However, these relationships were found to be stronger between the EL-FAME and PLFA results, indicating that reliability of the fatty-acid based methods is higher than that of the qPCR. Further, soil basal respiration was associated to a higher extent with total, bacterial, and fungal abundances captured by EL-FAME and PLFA analyses than with those measured by qPCR, which suggests that the first two methods are most closely related to the soil living microbial community. In general, dynamics in the abundance of total and bacterial communities were better captured than those of fungi. The PLFA analysis seems to perform better than the EL-FAME method in forest soil and in detecting the small antibiotic-induced decreases in microbial abundances. Since the EL-FAME method is cheaper and allows a much faster processing of samples than the PLFA method, and the reliability of both methods is similar in detecting rapid changes of soil microbial abundances, choosing EL-FAME over PLFA may be advantageous in most cases.

microbiology↗

bioRxiv2022

Chilean bee diversity: Contrasting patterns of species and phylogenetic turnover along a large-scale ecological gradient

Chiles isolation and varied climates have driven the evolution of a unique biodiversity with a high degree of endemism. The Mediterranean-type biome of Central Chile is one of 35 global biodiversity hotspots and has been highlighted as one of Chiles most endangered areas. It is threatened by anthropogenic land use change impacting the integrity of local biomes and associated species. This area holds the most extensive collections of the country with high endemicity regarding native bee species. Characterising habitat requirements of bees is a pressing priority to safeguard them and the ecosystem services they provide. We investigated broad-scale patterns of bee diversity using newly accessible expert-validated datasets comprising digitized specimen records from both Chilean and US collections and novel, expert-validated type specimen data for the bees of Chile. We used a generalised dissimilarity modelling (GDM) approach to explore both compositional and phylogenetic {beta}-diversity patterns across latitudinal, altitudinal, climate and habitat gradients in well-sampled bee assemblages in Central Chile. Using the GDM measures of increasing compositional and environmental dissimilarity we categorised and compared the most important drivers of these patterns and used them to classify wild bee ecoregions (WBE) representing unique assemblages. Turnover of bee assemblages was explained primarily by latitudinal variation (proxy for climate) along Chile. However, temperature variations, precipitation and the presence of bare soil also significantly explained the observed patterns. In comparison, we observed less turnover in phylogenetic biodiversity corresponding to spatial gradients. We were able to develop six de novo ecoregions (WBE) all with distinct taxa, endemic lineages, and representative species. The WBE represent distinct spatial classifications but have similarities to existing biogeographical classifications, ecosystems and bioclimatic zones. This approach establishes the baseline needed to prioritise bee species conservation efforts across this global biodiversity hotspot. We discuss the novelty of this classification considering previous biogeographical characterisations and its relevance for assessing conservation priorities for bee conservation. We argue that Chiles WBE show areas requiring funding for bee species exploration and description, distribution mapping and strengthening of conservation policies.

ecology↗

bioRxiv2020

CALCIUM-BINDING PROTEINS ARE ALTERED IN THE CEREBELLUM IN SCHIZOPHRENIA

Alterations in the cortico-cerebellar-thalamic-cortical circuit might underlie the diversity of symptoms in schizophrenia. However, molecular changes in cerebellar neuronal circuits, part of this network, have not yet been fully determined. Using LC-MS/MS, we screened altered candidates in pooled grey matter of cerebellum from schizophrenia subjects who committed suicide (n=4) and healthy individuals (n=4). Further validation by immunoblotting of three selected candidates was performed in two cohorts comprising schizophrenia (n=20), non-schizophrenia suicide (n=6) and healthy controls (n=21). We found 99 significantly altered proteins, 31 of them previously reported in other brain areas by proteomic studies. Transport function was the most enriched category, while cell communication was the most prevalent function. For validation, we selected the vacuolar proton pump subunit 1 (VPP1), from transport, and two EF-hand calcium-binding proteins, calmodulin and parvalbumin from cell communication. All candidates showed significant changes in schizophrenia (n=7) compared to controls (n=7). VPP1 was altered in the non-schizophrenia suicide group and increased levels of parvalbumin were linked to antipsychotics. Further validation in an independent cohort of non-suicidal chronic schizophrenia subjects (n=13) and non-psychiatric controls (n=14) showed that parvalbumin was increased while calmodulin was decrease in schizophrenia. Our findings provide evidence of an dysregulation of calcium-binding proteins in the cerebellum in schizophrenia, suggesting an impact on normal calcium-dependent synaptic functioning of cerebellar circuits. Our study also links VPP1 to suicide behaviours, suggesting a possible impairment in vesicle neurotransmitter refilling and release in these phenotypes.

neuroscience↗