11 research outputs found
The impact of HII regions on Giant Molecular Cloud properties in nearby galaxies sampled by PHANGS ALMA and MUSE
We identify giant molecular clouds (GMCs) associated with HII regions for a
sample of 19 nearby galaxies using catalogs of GMCs and H regions released by
the PHANGS-ALMA and PHANGS-MUSE surveys, using the overlap of the CO and
H{\alpha} emission as the key criterion for physical association. We compare
the distributions of GMC and HII region properties for paired and non-paired
objects. We investigate correlations between GMC and HII region properties
among galaxies and across different galactic environments to determine whether
GMCs that are associated with HII regions have significantly distinct physical
properties to the parent GMC population. We identify trends between the
H{\alpha} luminosity of an HII region and the CO peak brightness and the
molecular mass of GMCs that we tentatively attribute to a direct physical
connection between the matched objects, and which arise independently of
underlying environmental variations of GMC and HII region properties within
galaxies. The study of the full sample nevertheless hides a large variability
galaxy by galaxy. Our results suggests that at the ~100 pc scales accessed by
the PHANGS-ALMA and PHANGS-MUSE data, pre-supernova feedback mechanisms in HII
regions have a subtle but measurable impact on the properties of the
surrounding molecular gas, as inferred from CO observations
Enhanced oxidative-stress defense in transgenic potato expressing tomato Cu,Zn superoxide dismutases
A Comprehensive Analysis of Replicative Lifespan in 4,698 Single-Gene Deletion Strains Uncovers Conserved Mechanisms of Aging
Many genes that affect replicative lifespan (RLS) in the budding yeast Saccharomyces cerevisiae also affect aging in other organisms such as C. elegans and M. musculus. We performed a systematic analysis of yeast RLS in a set of 4,698 viable single-gene deletion strains. Multiple functional gene clusters were identified, and full genome-to-genome comparison demonstrated a significant conservation in longevity pathways between yeast and C. elegans. Among the mechanisms of aging identified, deletion of tRNA exporter LOS1 robustly extended lifespan. Dietary restriction (DR) and inhibition of mechanistic Target of Rapamycin (mTOR) exclude Los1 from the nucleus in a Rad53-dependent manner. Moreover, lifespan extension from deletion of LOS1 is nonadditive with DR or mTOR inhibition, and results in Gcn4 transcription factor activation. Thus, the DNA damage response and mTOR converge on Los1-mediated nuclear tRNA export to regulate Gcn4 activity and aging