Peptide self‐assembly as a strategy for facile immobilization of redox enzymes on carbon electrodes

Redox-enzyme‐mediated electrochemical processes such as hydrogen production,nitrogen fixation,and CO_(2) reduction are at the forefront of the green chemistry revolution.To scale up,the inefficient two‐dimensional(2D)immobilization of redox enzymes on working electrodes must be replaced by an efficient dense 3D system.Fabrication of 3D electrodes was demonstrated by embedding enzymes in polymer matrices.However,several requirements,such as simple immobilization,prolonged stability,and resistance to enzyme leakage,still need to be addressed.The study presented here aims to overcome these gaps by immobilizing enzymes in a supramolecular hydrogel formed by the self‐assembly of the peptide hydrogelator fluorenylmethyloxycarbonyldiphenylalanine.Harnessing the self‐assembly process avoids the need for tedious and potentially harmful chemistry,allowing the rapid loading of enzymes on a 3D electrode under mild conditions.Using the[FeFe]hydrogenase enzyme,high enzyme loads,prolonged resistance against electrophoresis,and highly efficient hydrogen production are demonstrated.Further,this enzyme retention is shown to arise from its interaction with the peptide nanofibrils.Finally,this method is successfully used to retain other redox enzymes,paving the way for a variety of enzyme‐mediated electrochemical applications.

Conserved H3K27me3-associated chromatin looping mediates physical interactions of gene clusters in plants

Higher-order chromatin organization is essential for transcriptional regulation,genome stability maintenance,and other genome functions.Increasing evidence has revealed significant differences in 3D chromatin organization between plants and animals.However,the extent,pattern,and rules of chromatin organization in plants are still unclear.In this study,we systematically identified and characterized long-range chromatin loops in the Arabidopsis 3D genome.We identified hundreds of long-range cis chromatin loops and found their anchor regions are closely associated with H3K27me3 epigenetic modifications.Furthermore,we demonstrated that these chromatin loops are dependent on Polycomb group(PcG)proteins,suggesting that the Polycomb repressive complex2(PRC2)complex is essential for establishing and maintaining these novel loops.Although most of these PcG-medicated chromatin loops are stable,many of these loops are tissue-specific or dynamically regulated by different treatments.Interestingly,tandemly arrayed gene clusters and metabolic gene clusters are enriched in anchor regions.Long-range H3K27me3-marked chromatin interactions are associated with the coregulation of specific gene clusters.Finally,we also identified H3K27me3-associated chromatin loops associated with gene clusters in Oryza sativa and Glycine max,indicating that these long-range chromatin loops are conserved in plants.Our results provide novel insights into genome evolution and transcriptional coregulation in plants.

Germination strategies under climate change scenarios along an aridity gradient

由于年降雨量减少和变异性的增加,地中海东部地区的气候变化将对生态系统功能和植物群落动态产生重大影响。我们旨在了解种子库作为应对气候变化所导致的气候不确定性的潜在缓冲作用。我们研究了沿干旱梯度出现的18种常见物种的萌发策略。数据由干旱、半干旱、地中海和中等地中海生态系统连续九年内萌发的土壤种子库获得。在半干旱和地中海地区,采用了模拟30%干旱和30%降雨增加的降雨处理方法。在连续三个萌发季的最佳灌溉条件下检测了萌发策略,以确定每种土壤样品的总体种子萌发能力。使用一种新颖的统计方法研究了萌发策略的变化,该方法考虑了可能影响种子发芽性的气候和生物因素。研究结果表明,优势种通过产生具有不同年度发芽率概率的种子来控制其发芽率。可产生种子的降雨量导致了关于可萌发性的两种主要种子类型:高萌发性(可形成短暂种子库的种子)和低萌发性(可形成持久种子库的种子)。我们得出的结论是,两种类型的干湿年之间种子产生的差异沿干旱梯度建立了一个稳定的平衡,使土壤种子库可以充当稳定机制,以防止降雨的不可预测性。此外,我们提出了地中海和干旱生态系统中占主导地位的一年生物种萌发策略的一般模型,该模型加强了土壤种子库可以作为应对该地区气候变化引起的气候不确定性的缓冲剂的概念。