Resilience of breadfruit agro-ecosystems in Hawai'i during the COVID-19 pandemic.

Background: The COVID-19 pandemic is interrupting domestic and global food supply chains resulting in reduced access to healthy diverse diets. Hawai'i has been described as a model social-ecological system and it has been suggested that indigenous agro-ecosystems have the potential to be highly productive and resilient under changing land-use and climate change disturbance. However, little research has yet been conducted exploring the disruption and resilience of agro-ecosystems in Hawai'i caused by the COVID-19 pandemic.

Transcriptional remodeling in response to iron deprivation in Saccharomyces cerevisiae.

The budding yeast Saccharomyces cerevisiae responds to depletion of iron in the environment by activating Aft1p, the major iron-dependent transcription factor, and by transcribing systems involved in the uptake of iron. Here, we have studied the transcriptional response to iron deprivation and have identified new Aft1p target genes. We find that other metabolic pathways are regulated by iron: biotin uptake and biosynthesis, nitrogen assimilation, and purine biosynthesis.

Three cell wall mannoproteins facilitate the uptake of iron in Saccharomyces cerevisiae.

Analysis of iron-regulated gene expression in Saccharomyces cerevisiae using cDNA microarrays has identified three putative cell wall proteins that are directly regulated by Aft1p, the major iron-dependent transcription factor in yeast. FIT1, FIT2, and FIT3 (for facilitator of iron transport) were more highly expressed in strains grown in low concentrations of iron and in strains in which AFT1-1(up), a constitutively active allele of AFT1, was expressed. Northern blot analysis confirmed that FIT1, FIT2, and FIT3 mRNA transcript levels were increased 60-230-fold in response to iron deprivation in an Aft1p-dependent manner.

Desferrioxamine-mediated iron uptake in Saccharomyces cerevisiae. Evidence for two pathways of iron uptake.

In the yeast Saccharomyces cerevisiae, uptake of iron is largely regulated by the transcription factor Aft1. cDNA microarrays were used to identify new iron and AFT1-regulated genes. Four homologous genes regulated as part of the AFT1-regulon (ARN1-4) were predicted to encode members of a subfamily of the major facilitator superfamily of transporters.

Cell-cycle arrest and inhibition of G1 cyclin translation by iron in AFT1-1(up) yeast.

Although iron is an essential nutrient, it is also a potent cellular toxin, and the acquisition of iron is a highly regulated process in eukaryotes. In yeast, iron uptake is homeostatically regulated by the transcription factor encoded by AFT1. Expression of AFT1-1(up), a dominant mutant allele, results in inappropriately high rates of iron uptake, and AFT1-1(up) mutants grow slowly in the presence of high concentrations of iron.