Biology subjects

Giorgi, F.

Publications and source records attributed to Giorgi, F..

3 recordsLinked to original sources

bioRxiv2025

KDM7-mediated oxygen sensing reprograms chromatin to enhance hypoxia tolerance in the root

Roots frequently encounter low oxygen (hypoxia) from soil compaction or water saturation and must adapt to this stress. We investigated how root tip cells sense hypoxia and adjust the meristem epigenome to activate genes that promote tolerance and growth under oxygen limitation. In Arabidopsis root tips, hypoxia tolerance was linked to increased trimethylation of histone H3 at lysine 4 (H3K4me3). We also found that group 7 demethylases (KDM7s) are directly inhibited by hypoxia, and that genetic inactivation of KDM7s, like hypoxia, induces expression of genes essential for meristem survival under oxygen deprivation. We propose that KDM7s function as root-specific oxygen sensors that prime and support hypoxia tolerance.

plant biology↗

bioRxiv2024

Real-time label-free exploration of the dynamics and interactions of bacteriophages

1.Bacteriophages are the focus of extensive research and monitoring their dynamics and interactions with bacterial hosts is crucial to characterise the mechanisms of infection and support potential applications in biotechnology and medicine. Traditional monitoring techniques rely on the fluorescent labelling of bacteriophages due to their size being nanometric. In this paper, we propose a novel, label-free method to generate optical signatures of bacteriophages in a conventional microscopy setup by exploiting the optical phenomenon of caustics. We utilised previously isolated Pseudomonas aeruginosa phage (pelp20 and phiKZ) and a novel Escherichia coli phage (EcoLiv25) to demonstrate detection and tracking within liquid laboratory media. The results obtained confirm the feasibility of visualising and monitoring over time a diverse array of bacteriophages, offering a simpler and less invasive means of observation for research and application in microbiology and related fields.

microbiology↗

bioRxiv2021

One gene - two proteins: The C-terminus of the prototypical M2 muscarinic receptor localizes to the mitochondria

Muscarinic acetylcholine receptors are prototypical G protein-coupled receptors (GPCRs), members of a large family of seven transmembrane receptors mediating a wide variety of extracellular signals. We show here, in cultured cells and in a murine model, that the carboxyl terminal fragment of the muscarinic M2 receptor, comprising the transmembrane regions 6 and 7 (M2tail), is expressed by virtue of an internal ribosome entry site localized in the third intracellular loop. Single cell imaging and import in isolated yeast mitochondria reveals that M2tail, whose expression is upregulated in cells undergoing integrated stress response, does not follow the normal route to the plasma membrane, but is almost exclusively sorted to the mitochondria inner membrane: here it controls oxygen consumption, cell proliferation and the formation of reactive oxygen species by reducing oxidative phosphorylation. Crispr/Cas9 editing of the key methionine where cap-independent translation begins in human induced pluripotent stem cells, reveals the physiological role of this process in influencing cell proliferation and oxygen consumption at the endogenous level. The expression of the C-terminal domain of a GPCR, capable of regulating mitochondrial function, constitutes a hitherto unknown mechanism notably unrelated to its canonical signalling function as a GPCR at the plasma membrane. This work thus highlights a potential novel mechanism thar cells may use for controlling their metabolism under variable environmental conditions, notably as a negative regulator of cell respiration.

cell biology↗