Architecture of the ATP-driven motor for protein import into chloroplasts

Thousands of nuclear-encoded proteins are transported into chloroplasts through the TOC–TIC translocon that spans the chloroplast envelope membranes.A motor complex pulls the translocated proteins out of the TOC–TIC complex into the chloroplast stroma by hydrolyzing ATP.The Orf2971–FtsHi complex has been suggested to serve as the ATP-hydrolyzing motor in Chlamydomonas reinhardtii,but little is known about its architecture and assembly.Here,we report the 3.2-Åresolution structure of the Chlamydomonas Orf2971–FtsHi complex.The 20-subunit complex spans the chloroplast inner envelope,with two bulky modules protruding into the intermembrane space and stromal matrix.Six subunits form a hetero-hexamer that potentially provides the pulling force through ATP hydrolysis.The remaining subunits,including potential enzymes/chaperones,likely facilitate the complex assembly and regulate its proper function.Taken together,our results provide the structural foundation for a mechanistic understanding of chloroplast protein translocation.

Spatiotemporal distribution,environmental risk and carbon emission reduction potential of livestock manure in Shaanxi Province,China

Shaanxi is a leading province in animal husbandry(AH)in China.However,the lack of provincial information on the characteristics and utilization potential of livestock manure(LM)hinders crucial management decisions.Therefore,we investigated the spatiotemporal distribution,availability and biogas potential of LM in Shaanxi,and examine the carbon emission reduction potential of AH.There has been a 1.26-fold increase in LM quantities in Shaanxi over the past 35 years,reaching 4635.6×10^(4)t by 2021.LM was mainly concentrated in northern Shaanxi and the eastern part of Hanzhong.Cattle and pig manure were the primary sources of LM,with the average LM land-load of 14.57 t·ha^(−1)in 2021.While the overall AH in Shaanxi has not exceeded the environmental capacity,the actual scales of AH in Ankang and Hanzhong have already surpassed the respective environmental capacities,posing a higher risk of N and P pollutions.In 2021,the estimated biogas energy potential of LM was 1.2×10^(11)MJ.From 2012 to 2021,the average carbon emission reduction potential in Shaanxi was 22%,with an average potential scale of 10%.The results of this research provide valuable data and policy recommendations for promoting the intensive use of LM and reducing carbon emissions in Shaanxi.

Preparation and characterization of MgO hybrid biochar and its mechanism for high efficient recovery of phosphorus from aqueous media

Conversion of organic waste into engineered metal-biochar composite is an effective way of enhancing biochar’s efficiency for adsorptive capture of phosphorus(P)from aqueous media.Thus,various strategies have been created for the production of metal-biochar composites;however,the complex preparation steps,high-cost metal salt reagent application,or extreme process equipment requirements involved in those strategies limited the large-scale production of metal-biochar composites.In this study,a novel biochar composite rich in magnesium oxides(MFBC)was directly produced through co-pyrolysis of magnesite with food waste;the product,MFBC was used to adsorptively capture P from solution and bio-liquid wastewater.The results showed that compared to the pristine food waste biochar,MFBC was a uniformly hybrid MgO biochar composite with a P capture capacity of 523.91 mg/g.The capture of P by MFBC was fitted using the Langmuir and pseudo-first-order kinetic models.The P adsorptive capture was controlled by MgHPO4 formation and electrostatic attraction,which was affected by the coexisting F−and CO_(3)^(2−)ions.MFBC could recover more than 98%of P from the solution and bio-liquid wastewater.Although the P-adsorbed MFBC showed very limited reusability but it can be substituted for phosphate fertiliser in agricultural practices.This study provided an innovative technology for preparing MgO-biochar composite against P recovery from aqueous media,and also highlighted high-value-added approaches for resource utilization of bio-liquid wastewater and food waste.