Biology subjects

Lazaro-Cote, A.

Publications and source records attributed to Lazaro-Cote, A..

2 recordsLinked to original sources

bioRxiv2026

Mucus transcriptional profiling as a minimally invasive approach to identify thermal stress in a stenothermal salmonid

Global climate change has increased the frequency and severity of stressful temperatures that freshwater fishes experience, necessitating rapid and sensitive methods to monitor wild populations. Tissues used to measure transcriptional responses traditionally involved invasive or lethal sampling, which may be undesirable for imperilled species. Epidermal mucus offers a non-lethal and minimally invasive alternative, but whether thermal thresholds can be detected in mucus to identify fish experiencing thermal stress is unclear. Bull trout (Salvelinus confluentus) are a legally protected salmonid and cold-water specialist, generally occupying waters 12 {degrees}C and below, with higher temperatures resulting in cellular stress. Therefore, we measured a suite of 56 genes using high-throughput qPCR to compare machine learning classifiers developed with transcriptional profiles of epidermal mucus, gill, liver, and muscle to classify laboratory reared juvenile bull trout as below (9 {degrees}C, 12 {degrees}C) or above (15 {degrees}C, 18 {degrees}C) cellular thermal thresholds. Mucus profiles most resembled gills but represented an intermediate transcriptional response to all tissues. A reduced biomarker panel of 10 genes in mucus assigned fish to stress categories with 94.1% (95% CI = 71.3-99.9%) accuracy, which was comparable to gill (100.0%, CI = 82.4- 100%), liver (95.0%, CI = 75.1-99.9%), and muscle (100.0%, CI = 80.5-100.0%). Sex-specific temperature effects were evident in all tissues, but less pronounced in mucus and gill than in liver and muscle. Our findings demonstrate that transcriptional profiling of mucus can reliably identify individuals experiencing thermal stress, highlighting the promise of this non-lethal approach for monitoring at-risk species.

genomics↗

bioRxiv2025

Cumulative effects of high temperature and low dissolved oxygen alter the acute thermal tolerance and cellular stress response in lake trout

Lake trout (Salvelinus namaycush) is an important food fish in Northern communities, inhabiting cool, well-oxygenated water. Yet, climate change is reducing available habitat with extended summer stratification of lakes creating an upper thermal barrier ([~]15 {degrees}C) and lower dissolved oxygen (DO) boundary (4-7 mg L-1). Together, these environmental factors can influence tolerance thresholds and climate change may lead to abiotic factors exceeding these physiological thresholds in lake trout habitats. Thresholds can shift with environmental acclimation in lake trout populations, but the functional basis of this shift has yet to be examined. The abundance of mRNA transcripts offers insight into underlying cellular responses to environmental stressors that can provide an early warning of fitness consequences. Here, we used a stress-response transcriptional profiling chip to investigate a suite of genes involved in thermal and general stress in lake trout acclimated to a range of temperatures (6-18 {degrees}C) and DO (normoxia: > 8.5 mg L-1 or hypoxia: 5.5-6.5 mg L-1), as well as following an acute thermal stress (i.e., CTmax). Transcriptional profiles were assessed in the gill, liver, and and epidermal mucus. Generally, fish acclimated to the greatest combined stressor (18 {degrees}C and hypoxia) had the largest transcriptional response, suggestive of a transition from a routine stress response to an extreme survival response. A noted temperature dependence occurred in liver tissue, which was not evident in gill or mucus tissues. Further, transcriptional responses in the gill and mucus were highly correlated (r = 0.74-0.87), highlighting the potential use of these tissues for non-lethal sampling methods to enhance management and conservation strategies for lake trout across their distribution.

physiology↗