Biology subjects

Gitton, C.

Publications and source records attributed to Gitton, C..

4 recordsLinked to original sources

bioRxiv2026

Macrophages from Holstein and Normande cows respond differently to Escherichia coli and Streptococcus uberis

Macrophages, alongside mammary epithelial cells, are major contributors to the innate immune response triggered by bacterial invasion of the mammary gland. To investigate breed-specific immune mechanisms, we stimulated monocyte-derived macrophages from Holstein and Normande cattle with Escherichia coli and Streptococcus uberis, two major mastitis pathogens. We monitored bacterial survival using [methode] and profiled gene expression via RNA-seq. E. coli exhibited significantly higher survival 6 hours post-infection compared to S. uberis (p < 0.05). Moreover, E. coli induced a robust transcriptional response, with 4403 differentially expressed genes (FDR < 0.05, |log2FC| > 1), versus only 813 for S. uberis. Qualitative differences were also observed: genes such as CCL2 and CSF1 were uniquely induced by S. uberis. Additionally, macrophages from Holstein and Normande cattle showed distinct expression profiles: 185, 45, and 174 genes were differentially expressed at steady state or after E. coli or S. uberis stimulation, respectively. These genes were enriched in immune-related pathways. Overall, our results demonstrate a stronger response to E. coli, although S. uberis specifically induces a subset of genes. The observed breed-specific differences may reflect underlying immune mechanisms that could influence disease susceptibility, warranting further functional validation.

pathology↗

bioRxiv2025

Gene expression profiling of bovine raw milk is linked to the inflammatory status of the udder

Inflammation of the mammary gland, or mastitis, is a common disease of dairy cows with important consequences on the economy of dairy farms, well-being of cows and antibiotic usage. Monitoring of the inflammatory status of mammary gland currently relies on milk somatic cell counting. In order to improve this monitoring, methods aiming at differentiating cell types among milk cells are being developed. The objective of the present study was to explore the use of gene expression profiling from raw milk samples to define the inflammatory status of udder quarters. A pilot study allowed us to select 37 genes differentially expressed between three milk cell types, i.e. neutrophils, macrophages or T lymphocytes. Based on expression data measured by RT-qPCR for these genes in RNA extracted from quarter milk samples, we were able to identify four different types of milk samples, each with specific properties. One cluster was characterized by increased expression of genes typifying neutrophils, a second one was identified by increased expression of genes typifying macrophages while the two others were distinguished based on the expression of genes associated with T lymphocytes. Clustering of samples based on gene expression was shown to be comparable to that obtained by flow cytometry analysis. Our results highlight the potential of profiling of milk samples based on gene expression for the analysis of the inflammatory status of udders.

pathology↗

bioRxiv2024

Emergence of Pre-movement Beta Activity with Stable Sensorimotor Predictions to Facilitate Motor Adjustments

Adaptive behavior enables flexible responses to environmental changes. This process is particularly crucial when transitioning between environments with different features, relying on the progressive formation of expectations based on prior experience. In humans, beta oscillations are central to adaptive behavior. Yet, the brain mechanisms underlying the detection of environmental changes, and the iterative update needed to progressively improve behavioral performance remain elusive. Here, we reveal that beta activity emerges in a cerebello-cortical network two seconds before action initiation, as the features of a new environment become known and behavioral outcomes become more predictable. Within this period, the cerebellum and parietal cortex drive prefrontal activity to form expectations. Using a single-trial approach, we establish that beta bursts before action initiation predict performance in the upcoming trial based on previous outcomes. These findings uncover a novel anticipatory mechanism that reflects predictive processes critical for stabilizing performance and adapting to environmental changes.

neuroscience↗

bioRxiv2020

Distinct neural variables underlie subjective reports of attention

Attention is subjectively experienced as a unified cognitive effort. This unitary experience of attention contrasts with the diversity of neural and peripheral correlates of attention. While the effects of attention on stimulus-evoked responses, alpha oscillations and pupil diameter, are well-known the relationship between these indices and the subjective experience of attention, has not yet been assessed. Participants performed a sustained (10 s to 30 s) attention task in which rare (10%) targets were detected within continuous tactile stimulation (16 Hz). Trials were followed by attention ratings on an 8-point Likert scale. Steady-state evoked fields (SSEFs) in response to tactile stimulation, as measured by magnetoencephalography, provided an objective measure of sensory processing. Beamformer source analysis of somatosensory alpha power was used as a measure of cortical excitability, while pupillometry provided a peripheral index of arousal. Attention ratings correlated negatively with contralateral somatosensory alpha power, and positively with pupil diameter. The effect of pupil diameter on attention ratings extended into the following trial, reflecting a sustained aspect of attention related to vigilance. The effect of alpha power did not carry over to the next trial, and furthermore mediated the effect of pupil diameter on attention ratings. Variation in SSEF power reflected stimulus processing under the influence of alpha oscillations, but were not readily expressed through subjective ratings of attention. Together, our results show that both alpha power and pupil diameter are reflected in the subjective experience of attention, albeit on different time spans, while continuous stimulus processing might not be metacognitively accessible. 1 Significance StatementAttention is subjectively experienced as a unified cognitive effort, in contrast with a diversity of neural and peripheral measures shown to correlate with attention. We present the first comprehensive study on the complex inter-relationship between the most common bio-physiological indices of attention, and their association with the subjective experience of attention. We show that the subjective experience of attention correlates negatively with cortical alpha oscillations, and positively with pupil diameter. The latter reflected a sustained aspect of attention, spanning several tens of seconds, related to vigilance. Alpha power, representing cortical control, fluctuated faster and mediated the effect of pupil diameter on attention. Tactile steady-state power reflected stimulus processing, also under the influence of alpha oscillations, but did not contribute much to subjective ratings of attention.

neuroscience↗