物理化学融合实验的设计与教学——以电动势测定实验为例

适应新时代社会经济的发展,需要加强创新型、应用型、技能型人才的培养,并将其落实到学生学习的全过程。在化学实验教学中,以全面的化学教育观为指导,针对验证性实验开展融合实验改革是一种有效策略。以物理化学电动势测定实验为例,这一改革旨在将验证性实验教学内容拓展为仿真实验、基础实验、探究实验、综合实验融为一体的仿真嵌入式实验——融合实验,通过引入虚拟仿真技术、教师自制仪器、教师科研成果等元素,发挥科研与教学的协同效力。融合实验的教学过程秉持学生中心,鼓励自主探究,注重思政渗透,强化科学方法和思维的训练,体现出鲜明的“产出导向”,对提高人才培养质量具有比较明显的作用。

CG hypermethylation of the bHLH39 promoter regulates its expression and Fe deficiency responses in tomato roots

Iron(Fe)is an essential micronutrient for all organisms,including plants,whose limited bioavailability restricts plant growth,yield,and nutritional quality.While the transcriptional regulation of plant responses to Fe deficiency have been extensively studied,the contribution of epigenetic modulations,such as DNA methylation,remains poorly understood.Here,we report that treatment with a DNA methylase inhibitor repressed Fe deficiency-induced responses in tomato(Solanum lycopersicum)roots,suggesting the importance of DNA methylation in regulating Fe deficiency responses.Dynamic changes in the DNA methylome in tomato roots responding to short-term(12 hours)and long-term(72 hours)Fe deficiency identified many differentially methylated regions(DMRs)and DMR-associated genes.Most DMRs occurred at CHH sites under short-term Fe deficiency,whereas they were predominant at CG sites following long-term Fe deficiency.Furthermore,no correlation was detected between the changes in DNA methylation levels and the changes in transcript levels of the affected genes under either short-term or long-term treatments.Notably,one exception was CG hypermethylation at the bHLH39 promoter,which was positively correlated with its transcriptional induction.In agreement,we detected lower CG methylation at the bHLH39 promoter and lower bHLH39 expression in MET1-RNA interference lines compared with wild-type seedlings.Virus-induced gene silencing of bHLH39 and luciferase reporter assays revealed that bHLH39 is positively involved in the modulation of Fe homeostasis.Altogether,we propose that dynamic epigenetic DNA methylation in the CG context at the bHLH39 promoter is involved in its transcriptional regulation,thus contributing to the Fe deficiency response of tomato.

利用重测序技术获取转基因植物T-DNA插入位点

T-DNA插入位点的获得对于植物功能基因组学研究及转基因植物的筛选鉴定非常重要,但是目前常用的方法如反向PCR、半随机引物PCR等,除了操作复杂、消耗时间长外,特异性较差,效率也很低。本研究利用全基因组重测序技术,将3份转基因材料基因组DNA打包后进行重测序,利用转基因载体序列作为参考序列进行比对分析,得到4个T-DNA插入位点。对3份转基因材料进行PCR和Southern blot验证分析,成功获得了3份转基因材料全部T-DNA插入位点,其中1份材料为2拷贝插入。本文利用重测序技术建立了一种简单、可靠、高效的获取转基因植物T-DNA插入位点的方法,以期为植物功能基因组学及转基因研究奠定基础。

侧翼序列获取技术研究进展

侧翼序列是指染色体中特定位点两侧的DNA序列,包含着候选基因、转录调控、染色体结构、生物安全等信息,在基因组学研究中具有重要的作用。侧翼序列获取技术主要应用于启动子和增强子等调控序列的克隆、鉴定T-DNA或转座子插入位点、染色体步移、全基因组空隙填补等,是结构基因组研究以及功能基因组研究的重要手段,在转基因动植物鉴定及安全管理等方面具有重要应用。随着分子生物学的发展,目前已经建立了许多侧翼序列的获取方法,依据技术原理可以分为质粒拯救法、反向PCR法、外源接头介导PCR法、半随机引物PCR法和基因组重测序法等5大类。本文系统总结了近年来侧翼序列获取技术的研究进展,并对这些技术的原理以及应用情况进行了较为系统的综述,为侧翼序列信息的获取提供参考。

Self-shrinking supramolecular nanoparticles syndicate energy suppression and NIR-II mild photothermal amplification of mitochondrial oxidative stress for breast cancer therapy

Photothermal therapy(PTT)may lead to healthy tissue damage,tumor metastasis,and recurrence,which makes mild photothermal therapy(mild PTT)stand out.However,overcoming heat resistance,insufficient therapeutic effect,and poor photothermal conversion efficiency has become new challenge.Herein,we report a dynamic supramolecular nanocarrier formed from amide-sericin and aldehyde-polyhydroxy glucan(denoted as SDA),the loose cavity of which can be filled by using the pharmaceutical combination of lonidamine(LND)and NIR-II photothermal agent of IR-1061,producing SDLI with a tighter inner hole,smaller and uniform particle size and excellent stability due to multiple pulling forces.Moreover,the intricate internal network structure prevents the hydrophobic IR-1061 from forming aggregates in the small cavity,and the photothermal conversion efficiency(PCE)can reach 48.9%.At the acidic tumor microenvironment of pH 6.5,the controlled release of LND can solve the problem of heat resistance of NIR-II mild PTT and significantly improve the therapeutic effect of NIR-II mild PTT.Meanwhile,SDLI also shows a reasonable tumor inhibition rate,so the synergistic strategy of inhibiting tumor energy metabolism and NIR-II mild PTT to magnify mitochondrial oxidative stress,continuous cell stress state-induced immunogenic cell death to promote the induction of tumor apoptosis is proposed to achieve more effective cancer treatment.

A novel protein domain is important for photosystem Ⅱ complex assembly and photoautotrophic growth in angiosperms

Photosystem Ⅱ(PSⅡ)is a multi-subunit protein complex of the photosynthetic electron transport chain that is vital to photosynthesis.Although the structure,composition,and function of PSⅡ have been extensively studied,its biogenesis mechanism remains less understood.Thylakoid rhodanese-like(TROL)provides an anchor for leaf-type ferredoxin:NADP^(+)oxidoreductase.Here,we report the chacterizaton of a second type of TROL protein,TROL2,encoded by seed plant genomes whose function has not previously been reported.We show that TROL2 is a PSⅡ assembly cofactor with essential roles in the establishment of photoautotrophy.TROL2 contains a 45-amino-acid domain,termed the chlorotic lethal seedling(CLS)domain,that is both necessary and sufficient for TROL2 function in PSⅡ assembly and photoautotrophic growth.Phylogenetic analyses suggest that TROL2 may have arisen from ancestral TROL1 via gene duplication before the emergence of seed plants and acquired the CLS domain via evolution of the sequence encoding its N-terminal portion.We further reveal that TROL2(or CLS)forms an assembly cofactor complex with the intrinsic thylakoid membrane protein LOW PSⅡ ACCUMULATION2 and interacts with small PSⅡ subunits to facilitate PSⅡ complex assembly.Collectively,our study not only shows that TROL2(CLS)is essential for photoautotrophy in angiosperms but also reveals its mechanistic role in PSⅡ complex assembly,shedding light on the molecular and evolutionary mechanisms of photosynthetic complex assemblyin angiosperms.

The miR157-SPL-CNR module acts upstream of bHLH101 to negatively regulate iron deficiency responses in tomato

Iron(Fe)homeostasis is critical for plant growth,development,and stress responses.Fe levels are tightly controlled by intricate regulatory networks in which transcription factors(TFs)play a central role.A series of basic helix-loop-helix(b HLH)TFs have been shown to contribute to Fe homeostasis,but the regulatory layers beyond b HLH TFs remain largely unclear.Here,we demonstrate that the SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE(SPL)TF Sl SPL-CNR negatively regulates Fe-deficiency responses in tomato(Solanum lycopersicum)roots.Fe deficiency rapidly repressed the expression of Sl SPL-CNR,and Fe deficiency responses were intensified in two clustered regularly interspaced palindromic repeats(CRISPR)/CRISPRassociated protein 9-generated Sl SPL-CNR knockout lines compared to the wild-type.Comparative transcriptome analysis identified 47 Fe deficiencyresponsive genes the expression of which is negatively regulated by Sl SPL-CNR,one of which,Slb HLH101,helps regulate Fe uptake genes.Sl SPLCNR localizes the nucleus and interacts with the GTAC and BOX 4(ATTAAT)motifs in the Slb HLH101 promoter to repress its expression.Inhibition of Sl SPL-CNR expression in response to Fe deficiency was well correlated with the expression of the micro RNA Slymi R157.Slymi R157-overexpressing tomato lines displayed enhanced Fe deficiency responses,as did Sl SPL-CNR loss-of-function mutants.We propose that the Slymi R157-Sl SPL-CNR module represents a novel pathway that acts upstream of Slb HLH101 to regulate Fe homeostasis in tomato roots.

Microenvironment-responsive chemotherapeutic nanogels for enhancing tumor therapy via DNA damage and glutathione consumption

Although targeted therapy and immunotherapy are now shining in the treatment of some cancers,chemotherapy is still the cornerstone of drug treatment for many cancer patients.The emergence of chemotherapy prodrugs can improve the drug activity and reduce the side effects of chemotherapy.When used,the tumor microenvironment has characteristics different from normal tissues,and the existence of the microenvironment provided a more convenient way to design responsive nanodrugs.Herein,we designed a glutathione(GSH)-responsive prodrug nanogels for enhancing tumor chemotherapy.In the nanogels of HHNP,10-hydroxycamptothecin(HCPT)played an essential role in killing cancer cells.HCPT was jointed with a cross-linker agent with disulfide bond and was further coated with polyethylene glycol,which not only prolonged the half-life of the drug,but also made HCPT accurate transport to the tumor fractions and achieved precise and controllable release.The proposal of HHNP effectively retained the biological activity of the drug,and introduced functions such as targeting,selective release and biodegradation,which greatly improved the medical efficiency of the drug and effectively reduced the toxic and side effects.This chemotherapeutic prodrug nanogel offers a new window for constructing efficient drug delivery platform.

A review on metal-organic frameworks for photoelectrocatalytic applications

Semiconductor-based photoelectrocatalytic processes have attracted considerable research interest for solar energy collection and storage.Photoelectrocatalysis is a heterogeneous photocatalytic process in which a bias potential is applied to a photoelectrode,and thus the photoelectrocatalytic performance is closely related to the photoelectrode prepared by semiconductors.Among various semiconductors,metal-organic frameworks(MOFs)have attracted more and more attention because of their unique properties such as optical properties and adjustable structure.Herein,a comprehensive review on different MOFs(Ti-based,Zn-based,Co-based,Fe-based,Cu-based,and mixed metal-based MOFs)for heterogeneous photoelectrocatalysis is carried out and,in particular,the application of this technique for CO2 conversion and water splitting is discussed.In addition,the challenges and development prospects of MOFs in photoelectrocatalysis are also presented.