Biology subjects

Mucha, S.

Publications and source records attributed to Mucha, S..

4 recordsLinked to original sources

bioRxiv2024

Tracking spatial patterns and nocturnal arousal in an undisturbed natural population of the pulse-type weakly electric fish Gymnotus omarorum

Assessing animals locomotor and activity-rest patterns in natural populations is challenging. It requires individual identification and behavioral tracking in sometimes complex and inaccessible environments. Weakly electric fish are advantageous models for remote monitoring due to their continuous emission of electric signals (EODs). Gymnotus omarorum is a South American freshwater pulse-type weakly electric fish. Previous manual recordings of restrained individuals in the wild showed a spatial distribution compatible with territoriality and a nocturnal increase in EOD rate interpreted as arousal. This interdisciplinary study presents the development of low-cost amplifiers for remote EOD recordings and the refinement of tracking algorithms that provide individual recognition of Gymnotus omarorum in the wild. We describe natural daily spacing patterns of undisturbed individuals that are compatible with territoriality, although heterogeneous across sampling sites, and confirm that all resident fish showed a robust nocturnal increase of EOD rate likely associated with daily variations of water temperature. HIGHLIGHTSO_LISuccessful remote individual tracking of wild pulse type weakly electric fish C_LIO_LIG. omarorum spacing patterns are compatible with known nocturnality and territoriality C_LIO_LIResidents keep their diurnal resting sites and move within small areas during the night C_LIO_LIThe robust nocturnal electric arousal of residents is linked to water temperature peak C_LI

animal behavior and cognition↗

bioRxiv2024

A microcontroller-based approach to control oxygen and establish flexible acclimation regimes

Environmental control systems are important tools for experimental researchers studying animal-environment interactions. Commercial systems for measurement and regulation of environmental oxygen conditions are relatively expensive and can not always be adapted to varying experimental applications. Here, we present a low-cost and highly flexible oxygen control system using Arduino microcontrollers in combination with a commercial optical oxygen sensor. We show dissolved oxygen (DO) measurements from three experiments that were conducted with mormyrid fish with different DO regimes: 1) acute challenge with defined rates of DO change from normoxia (> 90% air saturation) to hypoxia (10% air saturation), 2) acute stepwise hypoxia in a shuttle-box setup, and 3) long-term hypoxia (15 % air saturation) that was maintained for eight weeks in the home tank of the fish. Overall, the microcontroller-based DO control systems produced the desired experimental conditions with a high and inter-trial correlation (Pearsons R [≥] 0.987) and sufficient precision, except for the shuttle-box setup, where the lowest DO step of 10% air saturation could not be reached.

physiology↗

bioRxiv2020

The weakly electric fish, Apteronotus albifrons, avoids hypoxia before it reaches critical levels

Anthropogenic environmental degradation has led to an increase in the frequency and prevalence of aquatic hypoxia (low dissolved-oxygen concentration, DO), which may affect habitat quality for water-breathing fishes. The weakly electric black ghost knifefish, Apteronotus albifrons, is typically found in well-oxygenated freshwater habitats in South America. Using a shuttle-box design, we exposed juvenile A. albifrons to a stepwise decline in DO from normoxia (>95% air saturation) to extreme hypoxia (10% air saturation) in one compartment and chronic normoxia in the other. Below 22% air saturation, A. albifrons actively avoided the hypoxic compartment. Hypoxia avoidance was correlated with upregulated swimming activity. Following avoidance, fish regularly ventured back briefly into deep hypoxia. Hypoxia did not affect the frequency of their electric organ discharges. Our results show that A. albifrons is able to sense hypoxia at non-lethal levels and uses active avoidance to mitigate its adverse effects. SummaryThe weakly electric knifefish, Apteronotus albifrons, avoids hypoxia below 22% air saturation. Avoidance correlates with increased swimming activity, but not with a change in electric organ discharge frequency.

animal behavior and cognition↗

bioRxiv2019

A genome-wide genetic pleiotropy approach identified shared loci between multiple system atrophy and inflammatory bowel disease

We aimed to identify shared genetic background between multiple system atrophy (MSA) and autoimmune diseases by using the conjFDR approach. Our study showed significant genetic overlap between MSA and inflammatory bowel disease and identified DENND1B, C7, and RSP04 loci, which are linked to significant changes in methylation or expression levels of adjacent genes. We obtained evidence of enriched heritability involving immune/digestive categories. Finally, an MSA mouse model showed dysregulation of the C7 gene in the degenerating midbrain compared to wildtype mice. The results identify novel molecular mechanisms and implicate immune and gut dysfunction in MSA pathophysiology.

genetics↗