MaMADS1-MaNAC083 transcriptional regulatory cascade regulates ethylene biosynthesis during banana fruit ripening

The hormone ethylene is crucial in the regulation of ripening in climacteric fruit,such as bananas.The transcriptional regulation of ethylene biosynthesis throughout banana fruit ripening has received much study,but the cascaded transcriptional machinery of upstream transcriptional regulators implicated in the ethylene biosynthesis pathway is still poorly understood.Here we report that ethylene biosynthesis genes,including MaACS1,MaACO1,MaACO4,MaACO5,and MaACO8,were upregulated in ripening bananas.NAC(NAM,ATAF,CUC)transcription factor,MaNAC083,a ripening and ethylene-inhibited gene,was discovered as a potential binding protein to the MaACS1 promoter by yeast one-hybrid screening.Further in vitro and in vivo experiments indicated that MaNAC083 bound directly to promoters of the five ethylene biosynthesis genes,thereby transcriptionally repressing their expression,which was further verified by transient overexpression experiments,where ethylene production was inhibited through MaNAC083-modulated transcriptional repression of ethylene biosynthesis genes in banana fruits.Strikingly,MaMADS1,a ripening-induced MADS(MCM1,AGAMOUS,DEFICIENS,SRF4)transcription factor,was found to directly repress the expression of MaNAC083,inhibiting trans-repression of MaNAC083 to ethylene biosynthesis genes,thereby attenuating MaNAC083-repressed ethylene production in bananas.These findings collectively illustrated the mechanistic basis of a MaMADS1-MaNAC083-MaACS1/MaACOs regulatory cascade controlling ethylene biosynthesis during banana fruit ripening.These findings increase our knowledge of the transcriptional regulatory mechanisms of ethylene biosynthesis at the transcriptional level and are expected to help develop molecular approaches to control ripening and improve fruit storability.

Microstructure and Properties of an Advanced Nickel-base PM Superalloy

The need for nickel-base powder metallurgy （PM） superalloy turbine discs is becoming increasingly evi dent. With the eventual aim of improving thrust-to-weight ratio of aeroengines for power generation, well integration of significantly high strength, high damage tolerance and high-temperature capability would be reasonably required. An advanced PM superalloy, which was designed for applications up to 815- 8 5 0 ℃, was experimentally investigated. Emphasis was primarily put on microstructure and mechanical properties. The results indicated the measured phases in the sample were composed of γ,γ＇, MC, and Ma B2. With uniform coarse grain microstruc ture （ASTM 5-6）, the sample appeared to exhibit overwhelming superiority over the prior art materials FGH95, FGH96, FGH97 and FGH98. The dominant embodiments consisted of high tensile strength （Rm = 1000 MPa and Rp0.2 800 MPa at 850℃）, strong creep resistance （ξp 0.12% at 815 ℃/400 MPa/50 h）, and considerable stressrupture life （τ=457.4 h at 815 ℃/450 MPa）. The technical practicability of applications up to 815-850 ℃ of this alloy was conclusively proved.

Downregulation of miR-4772-3p promotes enhanced regulatory T cell capacity in malignant pleural effusion by elevating Helios levels

Background:Malignant pleural effusion(MPE)is a complicated condition of patients with advanced tumors.Further dissecting the microenvironment of infiltrated immune cells and malignant cells are warranted to understand the immune-evasion mechanisms of tumor development and progression.Methods:The possible involvement of microRNAs(miRNAs)in malignant pleural fluid was investigated using small RNA sequencing.Regulatory T cell(Treg)markers(CD4,CD25,forkhead box P3),and Helios(also known as IKAROS Family Zinc Finger 2[IKZF2])were detected using flow cytometry.The expression levels of IKZF2 and miR-4772-3p were measured using quantitative real-time reverse transcription polymerase chain reaction.The interaction between miR-4772-3p and Helios was determined using dual-luciferase reporter assays.The effects of miR-4772-3p on Helios expression were evaluated using an in vitro system.Correlation assays between miR-4772-3p and functional molecules of Tregs were performed.Results:Compared with non-malignant controls,patients with non-small cell lung cancer had an increased Tregs frequency with Helios expression in the MPE and peripheral blood mononuclear cells.The verified downregulation of miR-4772-3p was inversely related to the Helios*Tregs frequency and Helios expression in the MPE.Overexpression of miR-4772-3p could inhib让Helios expression in in vitro experiments.However,ectopic expression of Helios in induced Tregs reversed the effects induced by miR-4772-3p overexpression.Additionally,miR-4772-3p could regulate Helios expression by directly targeting IKZF2 mRNA.Conclusion:Downregulation of miR-4772-3p,by targeting Helios,contributes to enhanced Tregs activities in the MPE microenvironment.