Copper nanocluster‐based fluorescence enhanced determination of d‐penicillamine

Taking advantage of the compelling properties of d ‐penicillamine (d ‐PA) combined with copper, a method for the sensitive and selective determination of d ‐PA was established using copper nanocluster (Cu NC)‐based fluorescence enhancement. d ‐PA molecules containing a thiol compound showed a strong tendency to combine with the surface of Cu NCs, causing the re‐dispersion of nanoclusters and therefore fluorescence intensity was enhanced. Fluorescence enhancement efficiency of Cu NCs induced by d ‐PA was linear, with the d ‐PA concentration varying from 0.6–30 μg ml^?1 (R² = 0.9952) and with a detection limit of 0.54 μg ml^?1. d ‐PA content in human urine samples was detected with recoveries of 104.8–112.99%. Fluorescence‐enhanced determination of d ‐PA using Cu NCs was established for the first time and this rapid, easy and sensitive method should attract much attention for this application.     

Spatiotemporal Developmental Trajectories in the Arabidopsis Root Revealed Using High-Throughput Single-Cell RNA Sequencing

1. Download high-res image (327KB)
2. Download full-size image

     

Underestimated ecosystem carbon turnover time and sequestration under the steady state assumption: A perspective from long‐term data assimilation

It is critical to accurately estimate carbon (C) turnover time as it dominates the uncertainty in ecosystem C sinks and their response to future climate change. In the absence of direct observations of ecosystem C losses, C turnover times are commonly estimated under the steady state assumption (SSA), which has been applied across a large range of temporal and spatial scales including many at which the validity of the assumption is likely to be violated. However, the errors associated with improperly applying SSA to estimate C turnover time and its covariance with climate as well as ecosystem C sequestrations have yet to be fully quantified. Here, we developed a novel model‐data fusion framework and systematically analyzed the SSA‐induced biases using time‐series data collected from 10 permanent forest plots in the eastern China monsoon region. The results showed that (a) the SSA significantly underestimated mean turnover times (MTTs) by 29%, thereby leading to a 4.83‐fold underestimation of the net ecosystem productivity (NEP) in these forest ecosystems, a major C sink globally; (b) the SSA‐induced bias in MTT and NEP correlates negatively with forest age, which provides a significant caveat for applying the SSA to young‐aged ecosystems; and (c) the sensitivity of MTT to temperature and precipitation was 22% and 42% lower, respectively, under the SSA. Thus, under the expected climate change, spatiotemporal changes in MTT are likely to be underestimated, thereby resulting in large errors in the variability of predicted global NEP. With the development of observation technology and the accumulation of spatiotemporal data, we suggest estimating MTTs at the disequilibrium state via long‐term data assimilation, thereby effectively reducing the uncertainty in ecosystem C sequestration estimations and providing a better understanding of regional or global C cycle dynamics and C‐climate feedback.     

Synthesis and characterization of a photoresponsive doxorubicin/combretastatin A4 hybrid prodrug

To explore the application of photoremovable protecting groups (PPGs) in the field of combination chemotherapy, we designed and synthesized a photoresponsive hybrid prodrug 4 that bearing both doxorubicin (DOX) and combretastatin A4 (CA4). Light triggered drug release investigation found that DOX release was mainly accomplished by 405?nm light while CA4 release was mainly triggered by 365?nm light, i.e., prodrug 4 exhibited a quasi-sequential release behavior when a sequential light irradiation strategy was applied. Cell viability evaluation confirmed the increased cytotoxicity of prodrug 4 compared with individual drugs towards MDA-MB-231cells, indicating that a synergistic effect was achieved.     

利用红外相机公里网格调查钱江源国家公园的兽类及鸟类多样性

2014年5月至2019年4月, 作者采用红外相机技术调查了浙江省钱江源国家公园的兽类及鸟类多样性。将整个国家公园划分为267个1 km × 1 km的调查网格, 每个网格内设置3个固定调查位点, 使用1台红外相机定期在同一网格内的位点之间进行轮换。其中, 古田山片区在5年内共完成14轮次调查, 古田山以外的区域自2018年7月纳入调查范围, 何田、长虹片区完成2次轮换, 齐溪片区完成1次轮换。在253个网格内的741个有效位点上共获得140,413个相机工作日的数据, 采集兽类和鸟类的照片和视频268,833份, 有效探测数74,368次, 鉴定出21种野生兽类, 72种野生鸟类, 5种家畜及家禽。包括国家一级重点保护野生动物2种, 即黑麂(Muntiacus crinifrons)、白颈长尾雉(Syrmaticus ellioti); 国家二级重点保护野生动物17种, 合计占野生物种总数的20.4%。被IUCN物种红色名录评估为易危(VU)的5种, 近危(NT)的4种, 合计占物种总数的9.7%。被中国脊椎动物红色名录评估为濒危(EN)的1种, 易危(VU)的9种, 近危(NT)的10种, 合计占物种总数的21.5%。相对多度指数最高的大中型兽类为小麂(Muntiacus reevesi), 鸟类为白鹇(Lophura nycthemera)。本次调查获得了国家公园内兽类和鸟类的多样性组成、空间分布和相对多度, 为长期科研监测和科学管理提供了基础数据。     

关于贯彻落实“建立以国家公园为主体的自然保护地体系”的六项建议

<正>自2013年11月十八届三中全会提出"建立国家公园体制"以来,中国在不到5年时间中,以国家公园体制建设为契机,在全面深化自然保护地体制改革方面取得了里程碑式的重大进展,为实现生态文明和美丽中国国家战略奠定了坚实基础。为了更好地贯彻落实十九大报告提出的"建立以国家公     

野生矮牡丹高通量转录组测序分析

为探究野生稷山矮牡丹(Paeonia jishanensis)花青素等抗氧化活性物质生物合成的遗传基础,本文采用高通量测序技术Illumina NextSeqTM500对其幼嫩叶片、嫩茎和花芽混合池样本进行转录组测序分析。共获得39450个unigene,其中3563个unigene中有4106个SSR位点。在Swiss Prot数据库中注释到29420个unigene,其中11个与花青素生物合成过程相关,22个与类黄酮生物合成过程相关,15个与异黄酮生物合成过程相关;NR数据库中注释高达100%,有12个与类黄酮生物合成相关,7个与花青素生物合成相关;GO数据库中注释到24291个unigene,分为生物学过程、细胞组分及分子功能等三大类53个功能组,有21个unigene与黄酮、黄酮醇及异黄酮生物合成有关,4个unigene与花青素合成有关;eggNOG数据库中注释到38238个unigene,涉及植物生长发育过程绝大多数生命活动过程;KEGG数据库注释到5709个unigene,分别定位到6大类别42个代谢途径,其中25个unigene与花青素生物合成相关。研究表明,在稷山矮牡丹转录组序列中,共鉴定和发掘出多个涉及类黄酮化合物生物合成、花青素生物合成过程的相关基因序列及SSR位点,为下一步开展相关代谢合成途径研究奠定了基础。