Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: futurism – Page 71

3D epithelial cell topology tunes signaling range to promote precise patterning

Cell behaviors in multicellular organisms are coordinated via both diffusible molecules and by signals based on direct cell–cell contacts. The mode of cell communication used influences the signaling range. In many developing epithelia, contact-based Notch-Delta lateral inhibition signaling is used to pattern cell fates. While previous work revealed that cells can use protrusions to extend the range of Notch-Delta signaling to alter these patterns, this is not a general feature of epithelia. In addition, it is not known how the complex three-dimensional (3D) shapes of epithelial cells influence cell communication. In exploring this question, we show that epithelial cells at the Drosophila wing margin, which lack basal protrusions, contact different neighbors at different heights along their apico-basal axis, effectively increasing the number of neighbors each cell touches.

Metabolism by ex vivo cultures of human stool increases the activity of coumarin, a widespread antioxidant from herbal supplements

Mingolelli et al. characterize microbiome metabolism of coumarin in ex vivo cultures from human stool. Seventeen gut species reduce coumarin to 3,4-dihydrocoumarin and melilotic acid, including E. coli, through an N-ethylmaleimide-reductase-dependent pathway. Gut metabolites demonstrate increased antioxidant activity compared to either coumarin or its host metabolite, umbelliferone.

Hippocampal ripples and replay reveal how brain recombines past knowledge for flexible planning

When facing new situations or problems, humans typically rely on knowledge they acquired in the past. Specifically, neuroscience studies suggest that the brain reorganizes past experiences and previously acquired knowledge, creating mental frameworks that can help humans to solve the problems they are facing. The recombination of past knowledge into new mental structures also allows humans to flexibly plan future actions in changing environments. Past studies suggest that two key brain regions contribute to this process, the hippocampus and the medial prefrontal cortex (mPFC).

The hippocampus is a brain structure that plays a key role in the formation of memories and spatial navigation. The mPFC, on the other hand, is known to support decision-making, planning, reasoning and the integration of information.

Researchers at Beijing Normal University, the Chinese Academy of Medical Sciences, University College London (UCL) and other institutes recently set out to investigate how the hippocampus and mPFC work together to combine past knowledge into new configurations. Their findings, published in Nature Neuroscience, suggest that this process is supported by brief bursts of high-frequency neural activity in the hippocampus, called hippocampal ripples, and the replay (i.e., re-activation) of past experiences in the brain.

/* */