Comparison of nitrification inhibitors for mitigating cadmium accumulation in pakchoi and their associated microbial mechanisms

The use of nitrification inhibitors has been suggested as a strategy to decrease cadmium(Cd)accumulation in crops.However,the most efficient nitrification inhibitor for mitigating crop Cd accumulation remains to be elucidated,and whether and how changes in soil microbial structure are involved in this process also remains unclear.To address these questions,this study applied three commercial nitrification inhibitors,namely,dicyandiamide(DCD),3,4-dimethylpyrazole phosphate(DMPP),and nitrapyrin(NP),to pakchoi.The results showed that both DCD and DMPP(but not NP)could efficiently decrease Cd concentrations in pakchoi in urea-and ammonium-fertilized soils.In addition,among the three tested nitrification inhibitors,DMPP was the most efficient in decreasing the Cd concentration in pakchoi.The nitrification inhibitors decreased pakchoi Cd concentrations by suppressing acidification-induced Cd availability and reshaping the soil microbial structure;the most effective nitrification inhibitor was DMPP.Ammonia oxidation generates the most protons during nitrification and is inhibited by nitrification inhibitors.Changes in environmental factors and predatory bacterial abundance caused by the nitrification inhibitors changed the soil microbial structure and increased the potential participants in plant Cd accumulation.In summary,our study identified DMPP as the most efficient nitrification inhibitor for mitigating crop Cd contamination and observed that the soil microbial structural changes caused by the nitrification inhibitors contributed to decreasing Cd concentration in pakchoi.

Blockade of deubiquitinase YOD1 degrades oncogenic PML/RARα and eradicates acute promyelocytic leukemia cells

In most acute promyelocytic leukemia(APL)cells,promyelocytic leukemia(PML)fuses to retinoic acid receptor α (RARα)due to chromosomal translocation,thus generating PML/RARαoncoprotein,which is a relatively stable oncoprotein for degradation in APL.Elucidating the mechanism regulating the stability of PML/RARαmay help to degrade PML/RARαand eradicate APL cells.Here,we describe a deubiquitinase(DUB)-involved regulatory mechanism for the maintenance of PML/RARαstability and develop a novel pharmacological approach to degrading PML/RARαby inhibiting DUB.We utilized a DUB siRNA library to identify the ovarian tumor protease(OTU)family member deubiquitinase YOD1 as a critical DUB of PML/RARα.Suppression of YOD1 promoted the degradation of PML/RARα,thus inhibiting APL cells and prolonging the survival time of APL cell-bearing mice.Subsequent phenotypic screening of small molecules allowed us to identify ubiquitin isopeptidase inhibitor I(G5)as the first YOD1 pharmacological inhibitor.As expected,G5 notably degraded PML/RARαprotein and eradicated APL,particularly drug-resistant APL cells.Importantly,G5 also showed a strong killing effect on primary patient-derived APL blasts.Overall,our study not only reveals the DUB-involved regulatory mechanism on PML/RARαstability and validates YOD1 as a potential therapeutic target for APL,but also identifies G5 as a YOD1 inhibitor and a promising candidate for APL,particularly drug-resistant APL treatment.