基于H2DCFDA荧光探针的植物活性氧检测方法

活性氧(reactive oxygen species,ROS)是植物体内的一把“双刃剑”。ROS作为信号分子在植物生命活动中发挥关键作用,但ROS过量积累会对生物大分子造成氧化损伤。准确测定ROS含量对于评估植物细胞内的氧化还原状态至关重要。由于植物体内ROS各组分半衰期短且反应活性强,定性定量检测较为困难。因此,选择合适的检测方法以提高检测的时空准确性非常重要。目前,荧光分析法因其具有灵敏度高、选择性好、检出限低和直观性强等优点,受到研究人员的广泛关注。该文详细描述基于流式细胞仪和激光共聚焦显微镜,利用2′,7′-二氯二氢荧光素二乙酸酯(H2DCFDA)荧光探针检测水稻(Oryzasativa)体内ROS水平和时空分布的操作流程及注意事项。该技术也可用于直接检测拟南芥(Arabidopsis thaliana)、玉米(Zea mays)和大豆(Glycine max)等模式植物组织中ROS的水平和分布。

Preparation and Characterization of KNO3/Diatomite Shape-Stabilized Composite Phase Change Material for High Temperature Thermal Energy Storage

A new potassium nitrate （KNO3）]diatomite shape-stabilized composite phase change material （SS- CPCM） was prepared by the mixing and sintering method. KNO3 served as the phase change material （PCM） for thermal energy storage, while diatomite acted as the carrier matrix to provide the structural strength and prevent the leakage of PCM. It was found that KNO3 could be retained 65 wt% into pores and on surfaces of diatomite without the leakage of melted KNO3 from the SS-CPCM. The calculated filling rate of molten KNO3 that could enter into the disc-like shape pore of diatomite verified the scanning elec- tronic microscopy images of SS-CPCM. X-ray diffraction and Fourier transform infrared spectroscopy results showed that no reaction occurred between KNO3 and diatomite, performing good compatibility. Accord- ing to the differential scanning calorimetry results, after 50 thermal cycles, the phase change temperatures for melting and freezing of SS-CPCM with 65 wt% KNO3 were changed from 330.23 ℃ and 332.90 ℃ to 330.11 ℃ and 332.84 ℃ and corresponding latent heats varied from 60.52 J/g and 47.30 J/g to 54.64 J/g and 41.25 J/g, respectively. The KNO3/diatomite SS-CPCM may be considered as a potential storage media in solar power plants for thermal energy storage.

Serine 707 of APPL1 is Critical for the Synaptic NMDA Receptor-Mediated Akt Phosphorylation Signaling Pathway

Accumulating evidence indicates that the synaptic activation of N-methyl-o-aspartate receptors （NMDARs） has a neuroprotective effect on neurons. Our previous study demonstrated that APPL1 （adaptor protein containing pleckstrin homology domain, phosphotyrosine- binding domain, and leucine zipper motif） mediates the synaptic activity-dependent activation of PI3K-Akt signaling via coupling this pathway with NMDAR-PSD95 （postsynaptic density protein 95） complexes. However, the molecular mechanism underlying this process is still unknown. In the present study, we investigated the inter- action of APPL1 with PSD95 using co-immunocyto- chemical staining and western blotting. We found that the PDZ2 domain of PSD95 is a binding partner of APPL1. Furthermore, we identified serine 707 of APPL1, a pre- dicted phosphorylation site within the PDZ-binding motif at the C-terminus, as critical for the binding of APPL1 to PSD95, as well as for activation of the Akt signaling pathway during synaptic activity. This suggests that serine 707 of APPL1 is a potential phosphorylation site and may be involved in regulating the neuroprotective Akt signaling pathway that depends on synaptic NMDAR activity.

Nano-TiO_2 Decorated Radial-Like Mesoporous Silica: Preparation,Characterization, and Adsorption-Photodegradation Behavior

Supported nanocrystalline TiO2 with a diameter of 15–30 nm was prepared from previously synthesized radial mesoporous silica（RMS） by a post-synthesis method. In addition, their adsorption-photocatalytic activity toward the degradation of methylene blue（MB） was determined. RMS was tailor-made with the main template of CTAB and the SiO2 precursor of TEOS through a facile self-assembly process. The structural, morphological and textural properties of the well-designed TiO2/RMS samples were characterized.The RMS structure was retained after loading TiO2, but its surface area and pore diameter decreased as a result of partial pore blocking. The removal activity of MB for TiO2/RMS was significantly higher than that of commercial TiO2 nanoparticles. The optimal TiO2 loading（20 wt%） on the support could achieve the complete removal of MB within 70 min. The prepared TiO2/RMS particles can be easily separated and display good durability after six reaction cycles.

Influence of temperature and light gradient on leaf arrangement and geometry in cucumber canopies: Structural phenotyping analysis and modelling

Accurate structural phenotyping analysis is essential to understand plant architectural adaptation strategy to environment change.The aim of this study was to analyze leaf arrangement and geometry influenced by azimuthally generated light gradient;and to simulate static and heterogeneous cucumber canopies using regression equations by considering more geometric parameters.Three continuous measurements of structural organ parameters were obtained to fit the organ initiation and expansion curves.Four measurements with three density treatments were obtained to validate model accuracy.To describe leaf distribution and orientation characteristics in more detail,azimuth and elevation models were introduced into canopy structure modelling.Leaf distribution frequency was simulated based on leaf area index and solar elevation angle while leaf elevation was simulated based on leaf azimuth and acropetal phytomer number.This study provides an important basis for structural phenotyping analysis of cucumber canopy,which is essential for more accurate functional-structural modelling in the future.