Project description:The human pathogenic fungus Aspergillus fumigatus is readily eradicated by the innate immunity of immunocompetent human hosts, but can cause severe infections, such as invasive aspergillosis (IA), in immunocompromised individuals. During infection, the fungal redox homeostasis can be challenged by reactive oxygen (ROS) species, either derived from the oxidative burst of innate immune cells or the action of antifungal drugs. The peroxiredoxin Asp f3 was found to be essential to cause IA in mice, but how Asp f3 integrates to fungal redox homeostasis remains unknown. Here, we show that in vivo, Asp f3 acts as a sensor for ROS. While global transcription in fungal hyphae under minimal growth conditions was fully independent of Asp f3, a robust induction of the oxidative stress response required the presence of the peroxiredoxin. Hyphae devoid of Aspf 3 failed to activate several redox active genes, like members of the gliotoxin biosynthesis gene cluster and integral members of the Afyap1 regulon, the central activator of the ROS defence machinery in fungi. Upon deletion of the asp f3 gene Afyap1 displayed significantly reduced nuclear localization during ROS exposure, indicating that Asp f3 can act as an intracellular redox sensor for several target proteins
Project description:We determined the gene expression profiles of murine melan-a melanocytes treated with ASP or alpha-MSH over a 4 days time course using genome-wide oligonucleotide microarrays. As expected, the gene expression patterns emphasized the opposing effects of the 2 ligands, and there were significant reductions in expression of numerous melanogenic proteins elicited by ASP, which correlates with its inhibition of pigmentation. However, ASP also unexpectidly modulated the expression of genes involved in various other cellular pathways, including glutathione synthesis and redox metabolism. Many genes up-regulated by ASP are involved in morphogenesis, cell adhesion and ECM-receptor interactions.
Project description:We determined the gene expression profiles of murine melan-a melanocytes treated with ASP or alpha-MSH over a 4 days time course using genome-wide oligonucleotide microarrays. As expected, the gene expression patterns emphasized the opposing effects of the 2 ligands, and there were significant reductions in expression of numerous melanogenic proteins elicited by ASP, which correlates with its inhibition of pigmentation. However, ASP also unexpectidly modulated the expression of genes involved in various other cellular pathways, including glutathione synthesis and redox metabolism. Many genes up-regulated by ASP are involved in morphogenesis, cell adhesion and ECM-receptor interactions. Treatment with ASP or alpha-MSH was performed for 3 hr, 1 day, 2 days, 3 days and 4 days, in triplicate. Each biological replicate was submitted to a direct hybridization (treated/untreated samples) after coupling with Cy5 or Cy3 and to a reverse dye-swap, leading to 2 replicated hybridization for each biological sample. A total of 6 hybridized arrays was used for each of the 5 time points, for each drug.
Project description:Previously, we found that ASP-ASP-ASP-TYR (DDDY) from Dendrobium aphyllum has a minimum inhibitory concentration of 36.15 mg/mL against Pseudomonas aeruginosa. Here, we explored the antibacterial mechanism of DDDY and its potential preservation applications. Metabolomic and transcriptomic analyses revealed that DDDY mainly affects genes involved in P. aeruginosa membrane transport and amino acid metabolism pathways. Molecular dynamics simulation revealed that DDDY had a stronger effect on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine phospholipid membranes than on 1-palmitoyl-2-oleoyl-lecithin or 1-palmitoyl-2-oleoyl phosphatidylglycerol membranes, with high DDDY concentrations displaying stronger efficacy on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine. Mechanistically, the N-terminal of DDDY first bound to the phospholipid head group, while its C-terminal amino acid residue bound the hydrophobic tail, thereby creating a gap in the membrane when the phospholipids were clustered by hydrogen bonding. Finally, DDDY inhibited the growth of food microorganisms inoculated onto chestnut kernels, suggesting that DDDY is a promising antibacterial agent against multidrug-resistant gram-negative bacteria. Inhibitory effect of ASP-ASP-ASP-TYR (DDDY) from Dendrobium on Pseudomonas aeruginosa
Project description:ASP induces the expression of early auxin response genes by activates auxin response, and affects responses to other signals associated with the auxin signaling pathway. We used microarrays to detail the effect of ASP on Arabidopsis global gene expression, and identified distinct classes of up-regulated or down genes during this process
Project description:Thiol-dependent redox regulation is essential for the rapid adaptation of chloroplast metabolism to unpredictable changes of light intensity. The disulfide reductase activity of thioredoxins (Trxs), which relies on photo-reduced ferredoxin (Fdx) and a Fdx-dependent Trx reductase (FTR), constitutes the Fdx-FTR-Trxs system, which links chloroplast redox regulation to light. In addition, chloroplasts harbor an NADPH-dependent Trx reductase (NTR) with a joint Trx domain, NTRC. The activity of these two redox systems is integrated by the balance of the hydrogen peroxide scavenging enzyme 2-Cys peroxiredoxin (2-Cys Prx), which thus plays a key role in maintaining the reducing capacity of chloroplast Trxs in response to light intensity. Based on the severe phenotype of mutant lines lacking NTRC, it is clear that this enzyme plays an essential role in chloroplast redox homeostasis. However, whether the function of NTRC depends on its capacity of reduce 2-Cys Prxs or has additional targets remains unknown. Here, we have addressed this issue by a comparative analysis of the triple mutant of Arabidopsis thaliana, ntrc-2cpab, simultaneously lacking 2-Cys Prxs and NTRC, and the double mutant 2cpab lacking 2-Cys Prxs. The phenotype of the ntrc-2cpab mutant is indistinguishable of the 2cpab mutant, as shown by growth rate, photosynthesis performance, light-dependent redox regulation of enzyme activity and comparative transcriptomics based RNA-Seq. Based on these results, we propose that the function of NTRC in chloroplast redox homeostasis is exerted by the regulation of the redox balance of 2-Cys Prxs rather than by the direct reduction of additional targets.