Intensive land use enhances soil ammonia-oxidising archaea at a continental scale

Archaea are an important group of soil organisms that play key roles in carbon and nitrogen cycling, particularly in nitrification (ammonia oxidation) and methanogenesis. However, there are knowledge gaps regarding their importance in ecosystem processes relative to other microbial groups and how they may be impacted by land-use and environmental changes. Here, by carrying out a continental-scale sample collection and utilising archaea-specific primers for metabarcoding and shotgun metagenomics, we aimed to decipher the structure and function of archaeal communities across various land-use types in Europe. Metagenomic data reveal that land-use intensification increases the relative abundance of archaea, whereas bacteria and eukaryotes show no increase. Alongside this, ammonia oxidising archaea (AOA) increase as a proportion of the total metabarcoding reads, from 1 % of archaea in coniferous woodland to >90 % in croplands. Functional gene profiles reveal that land-use intensification shifts archaeal communities from adaptive metabolic pathways in forests to specialised, ammonia-oxidising microbes in fertiliser-enriched cropland soils. Our data suggest that land-use intensification may shift archaeal communities toward greater dependence on external nitrogen inputs, with potential consequences for soil fertility and greenhouse gas emissions

AML1-ETO fusion protein up-regulates TRKA mRNA expression in human CD34(+) cells, allowing nerve growth factor-induced expansion

The AML1-ETO fusion protein, generated by the t(8;21) in acute myeloid leukemia (AML), exerts dominant-negative functions and a variety of gains of function, including a positive effect on the growth of primary human CD34(+) hematopoietic stem/progenitor cells. We now show that AML1-ETO expression up-regulates the level of TRKA mRNA and protein in these cells and that AML1-ETO-expressing CD34(+) hematopoietic cells grown in the presence of five early-acting hematopoietic cytokines further proliferate in response to nerve growth factor (NGF). These cells also show a unique response to NGF and IL-3; namely, they expand in liquid culture. To determine the biological relevance of our findings, we analyzed 262 primary AML patient samples using real-time RT-PCR and found that t(8;21)-positive AML samples express significantly higher levels of TRKA mRNA than other subtypes of AML. NGF, which is normally expressed by bone marrow stromal cells, could provide important proliferative or survival signals to AML1-ETO-expressing leukemic or preleukemic cells, and the NGF/TRKA signaling pathway may be a suitable target for therapeutic approaches to AML