Activation of locus coeruleus noradrenergic neurons rapidly drives homeostatic sleep pressure.

Homeostatic sleep regulation is essential for optimizing the amount and timing of sleep for its revitalizing function, but the mechanism underlying sleep homeostasis remains poorly understood. Here, we show that optogenetic activation of locus coeruleus (LC) noradrenergic neurons immediately increased sleep propensity following a transient wakefulness, contrasting with many other arousal-promoting neurons whose activation induces sustained wakefulness. Fiber photometry showed that repeated optogenetic or sensory stimulation caused a rapid reduction of calcium activity in LC neurons and steep declines in noradrenaline/norepinephrine (NE) release in both the LC and medial prefrontal cortex (mPFC).

Manganese Peroxidase Participates in the Liquid-Solid-Gas Triphase Regulation on Microbial Degradation of Lignocellulose in Solid-State Fermentation.

The three-phase structure of solid-state fermentation (SSF) directly affects substrate degradation and fermentation efficiency. However, the mechanism of three-phase regulation on lignocellulose utilization and microbial metabolism is still unclear. Based on comparative transcriptome analysis, a lignocellulose degrading enzyme, manganese peroxidase (GlMnP), which was significantly affected by water stress meanwhile related to triphase utilization, was screened to reveal the mechanism using Ganoderma lucidum as the reference strain.

Gut Bacteria Encode Reductases that Biotransform Steroid Hormones.

The metabolism of steroids by the gut microbiome affects hormone homeostasis, impacting host development, mental health, and reproductive functions. In this study, we identify the Δ -3-ketosteroid 5β-reductase, 3β-hydroxysteroid dehydrogenase/Δ isomerase, and Δ -3-ketosteroid reductase enzyme families encoded by common human gut bacteria. Through phylogenetic reconstruction and mutagenesis, We show that 5β-reductase and Δ -3-ketosteroid reductase have evolved to specialize in converting diverse 3-keto steroid hormones into their 5β- and Δ -reduced derivatives.