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ABSTRACT The fungal pathogenCandida albicansmust acquire phosphate to colonize, infect, and proliferate in the human host.C. albicanshas four inorganic phosphate (P_i) transporters, Pho84 being the major high-affinity transporter; its cells can also use glycerophosphocholine (GPC) as their sole phosphate source. GPC is a lipid metabolite derived from deacylation of the lipid phosphatidylcholine. GPC is found in multiple human tissues, including the renal medulla, where it acts as an osmolyte.C. albicansimports GPC into the cell via the Git3 and Git4 transporters. Internalized GPC can be hydrolyzed to release P_i. To determine if GPC import and subsequent metabolism affect phosphate homeostasis upon P_ilimitation, we monitored growth and phenotypic outputs in cells provided with either P_ior GPC. Inpho84∆/∆ mutant cells that exhibit phenotypes associated with P_ilimitation, GPC provision rescued sensitivity to osmotic and cell wall stresses. The glycerophosphodiesterase Gde1 was required for phenotypic rescue of osmotic stress by GPC provision. GPC provision, like P_iprovision, resulted in repression of the PHO regulon and activation of TORC1 signaling. P_iuptake was similar to GPC uptake when phosphate availability was low (200 µM). While available at lower concentrations than P_iin the human host, GPC is an advantageous P_isource for the fungus because it simultaneously serves as a choline source. In summary, we find GPC is capable of substituting for P_iinC. albicansby many though not all criteria and may contribute to phosphate availability for the fungus in the human host. IMPORTANCECandida albicansis the most commonly isolated species from patients suffering from invasive fungal disease.C. albicansis most commonly a commensal organism colonizing a variety of niches in the human host. The fungus must compete for resources with the host flora to acquire essential nutrients such as phosphate. Phosphate acquisition and homeostasis have been shown to play a key role inC. albicansvirulence, with several genes involved in these processes being required for normal virulence and several being upregulated during infection. In addition to inorganic phosphate (P_i),C. albicanscan utilize the lipid-derived metabolite glycerophosphocholine (GPC) as a phosphate source. As GPC is available within the human host, we examined the role of GPC in phosphate homeostasis inC. albicans. We find that GPC can substitute for P_iby many though not all criteria and is likely a relevant physiological phosphate source forC. albicans. 

ABSTRACT Rotation curves of galaxies probe their total mass distributions, including dark matter. Dwarf galaxies are excellent systems to investigate the dark matter density distribution, as they tend to have larger fractions of dark matter compared to higher mass systems. The core-cusp problem describes the discrepancy found in the slope of the dark matter density profile in the centres of galaxies (β*) between observations of dwarf galaxies (shallower cores) and dark matter-only simulations (steeper cusps). We investigate β* in six nearby spiral dwarf galaxies for which high-resolution CO J = 1–0 data were obtained with ALMA (Atacama Large Millimeter/submillimeter Array). We derive rotation curves and decompose the mass profile of the dark matter using our CO rotation curves as a tracer of the total potential and 4.5 $$\mu$$m photometry to define the stellar mass distribution. We find 〈β*〉 = 0.6 with a standard deviation of ±0.1 among the galaxies in this sample, in agreement with previous measurements in this mass range. The galaxies studied are on the high stellar mass end of dwarf galaxies and have cuspier profiles than lower mass dwarfs, in agreement with other observations. When the same definition of the slope is used, we observe steeper slopes than predicted by the FIRE and NIHAO simulations. This may signal that these relatively massive dwarfs underwent stronger gas inflows towards their centres than predicted by these simulations, that these simulations overpredict the frequency of accretion or feedback events, or that a combination of these or other effects are at work.