Biology subjects

Espinoza, V.

Publications and source records attributed to Espinoza, V..

4 recordsLinked to original sources

bioRxiv2022

Acoustic and Neurophysiological Aspects of Lombard Effect

PurposeThis study aims to describe variations in acoustic and electroencephalography measures when speaking in the presence of background noise (Lombard effect) in participants with typical voice and normal hearing. MethodTwenty-one participants with typical voices and normal hearing uttered simple vocal tasks in three sequential background conditions: Baseline (in quiet), Lombard (in noise), and Recovery (five minutes after removing the noise). Acoustic and electroencephalography signals were recorded in all conditions. The noise used in the Lombard condition consisted of speech-shaped noise at 80 dB SPL sent by headphones. Acoustic measure, and ERP responses were analyzed. ResultsDuring the Lombard condition, the participants increased the intensity of their voice, accompanied by an increase in CPP, and a decrease in H1-H2. The cortical response was characterized by the increased N1-P2 complex amplitude of the ERP elicited by the subjects own vocalizations in noise, The source localization showed neural activities in frontal and temporal cortical regions. ConclusionsThe variation in acoustic measures due to the Lombard Effect could be modulated by temporal, and cortical regions.

neuroscience↗

bioRxiv2022

Identification of pre-existing microbiome and metabolic vulnerabilities to escalation of oxycodone self-administration and identification of a causal role of short-chain fatty acids in addiction-like behaviors.

The gut brain axis is thought to play a role in behavior and physiological responses through chemical, immunological, and metabolite signaling. Antibiotics, diet, and drugs can alter the transit time of gut contents as well as the makeup of the microbiome. Heterogeneity in genetics and environment are also well-known factors involved in the initiation and perpetuation of substance use disorders. Few viable genetic or biological markers are available to identify individuals who are at risk of escalating opioid intake. Primarily, the addiction field has focused on the nervous system, limiting the discovery of peripheral factors that contribute to addiction. To address this gap, we characterized the microbiome before and after drug exposure, and after antibiotics depletion in male and female heterogenous stock rats to determine if microbiome constituents are protective of escalation. We hypothesized that individuals that are prone to escalation of opioid self-administration will have distinct microbial and metabolic profiles. The fecal microbiome and behavioral responses were measured over several weeks of oxycodone self-administration and after antibiotic treatment. Antibiotic treatment reduces circulating short-chain fatty acids (SCFA) by depleting microbes that ferment fiber into these essential signaling molecules for the gut-brain axis. Depletion of the microbiome increased oxycodone self-administration in a subpopulation of animals (Responders). Supplementation of SCFAs in antibiotic depleted animals decreased elevated oxycodone self-administration. Phylogenetic functional analysis reveals distinct metabolic differences in the subpopulations of animals that are sensitive to antibiotic depletion and animals rescued by SCFA supplementation. In conclusion, this study identifies pre-existing microbiome and metabolic vulnerabilities to escalation of oxycodone self-administration, demonstrates that escalation of oxycodone self-administration dysregulates the microbiome and metabolic landscape, and identifies a causal role of short-chain fatty acids in addiction-like behaviors.

neuroscience↗

bioRxiv2021

Hypusinated eIF5A is required for the translation of collagen

The evolutionary conserved elongation factor eIF5A is required for the translation of mRNAs that encode protein sequences with consecutive prolines or combined with glycine and charged amino acids. Mammalian collagens are enriched in putative eIF5A-dependent Pro-Gly-containing tripeptides. Here, we show that eIF5A is needed for heterologous expression of collagen in yeast, and using a dual luciferase reporter system we confirmed that eIF5A depletion interrupts translation at Pro-Gly-collagenic motifs. Using mouse fibroblasts, we showed that depletion of active eIF5A reduced collagen 1 (Col1a1) content, which became concentrated around the nuclei, in contrast to a stronger and all over the cell collagen signal in untreated cells. Active eIF5A-depleted mouse fibroblast showed upregulation of endoplasmic reticulum (ER) stress markers, suggesting retention of partially synthesized Col1a1 in the ER. A dramatically lower level of Col11 protein was also observed in functional eIF5A-depleted human hepatic stellate cells treated with the profibrotic cytokine TGF-{beta}1. Our results show that collagen expression requires eIF5A and imply its potential as a target for regulating collagen production in fibrotic diseases.

molecular biology↗

bioRxiv2020

Multidimensionality in the thermal niches of dung beetles could limit species' responses to temperature changes

Understanding the consequences of climate change requires understanding how temperature controls species responses across key biological aspects, as well as the coordination of thermal responses across these aspects. We study the role of temperature in determining the species diel, seasonal, and geographical occurrence, using dung beetles as a model system. We found that temperature has relatively low -but not negligible- effects in the three spatiotemporal scales, once accounting for alternative factors. More importantly, the estimated thermal responses were largely incongruent across scales. This shows that species have multidimensional thermal niches, entailing that adjustments to fulfil temperature requirements for one biological aspect, such as seasonal ontogenetic cycles, may result in detrimental effects on other aspects, like diel activity. These trade-offs can expose individuals to inadequate temperatures, reducing populations performance. Paradoxically, the relatively weak effects of temperature we found may have serious consequences for species responses to warming if temperature regulates essential aspects of species biology in divergent ways.

ecology↗