Rotenone Directly Induces BV2 Cell Activation via the p38 MAPK Pathway

Parkinson’s disease (PD) is the second most common neurodegenerative disease. Although its pathogenesis is still unclear, increasing evidence suggests that mitochondrial dysfunction induced by environmental toxins, such as mitochondrial complex I inhibitors, plays a significant role in the disease process. The microglia in PD brains are highly activated, and inflammation is also an essential element in PD pathogenesis. However, the means by which these toxins activate microglia is still unclear. In the present study, we found that rotenone, a mitochondrial complex I inhibitor, could directly activate microglia via the nuclear factor kappa B (NF-κB) signaling pathway, thereby inducing significantly increased expression of inflammatory cytokines. We further observed that rotenone induced caspase-1 activation and mature IL-1β release, both of which are strictly dependent on p38 mitogen-activated protein kinase (MAPK). The activation of p38 is associated with the presence of reactive oxygen species (ROS) produced by rotenone. Removal of these ROS abrogated the activation of the microglia. Therefore, our data suggest that the environmental toxin rotenone can directly activate microglia through the p38 MAPK pathway.     

Using LiDAR Data to Measure the 3D Green Biomass of Beijing Urban Forest in China

The purpose of the paper is to find a new approach to measure 3D green biomass of urban forest and to testify its precision. In this study, the 3D green biomass could be acquired on basis of a remote sensing inversion model in which each standing wood was first scanned by Terrestrial Laser Scanner to catch its point cloud data, then the point cloud picture was opened in a digital mapping data acquisition system to get the elevation in an independent coordinate, and at last the individual volume captured was associated with the remote sensing image in SPOT5(System Probatoired''Observation dela Tarre)by means of such tools as SPSS (Statistical Product and Service Solutions), GIS (Geographic Information System), RS (Remote Sensing) and spatial analysis software (FARO SCENE and Geomagic studio11). The results showed that the 3D green biomass of Beijing urban forest was 399.1295 million m³, of which coniferous was 28.7871 million m³ and broad-leaf was 370.3424 million m³. The accuracy of 3D green biomass was over 85%, comparison with the values from 235 field sample data in a typical sampling way. This suggested that the precision done by the 3D forest green biomass based on the image in SPOT5 could meet requirements. This represents an improvement over the conventional method because it not only provides a basis to evalue indices of Beijing urban greenings, but also introduces a new technique to assess 3D green biomass in other cities.     

不同二步酶灌注法分离大鼠肝星状细胞的比较研究

目的:在现有二步酶灌注法分离大鼠肝星状细胞(hepatic stellate cells,HSC)的基础上,探索更加高效的分离HSC方法。方法:分别采用链酶蛋白酶+胶原酶循环灌注、链酶蛋白酶非循环灌注+胶原酶循环灌注以及胶原酶单独循环灌注法分离大鼠HSC,比较三种方法的细胞获得率、活性和纯度差异。应用0.4%台盼蓝染色判断活性,结蛋白(desmin)、波形蛋白(vimentin)细胞免疫荧光方法鉴定纯度。结果:链酶蛋白酶非循环灌注+胶原酶循环灌注法细胞获得率高于另两种方法,细胞活力高于链酶蛋白酶循环灌注+胶原酶循环灌注法,三组得到的细胞纯度均高于90%且无显著差异。结论:在三种二步酶灌注方法中,链酶蛋白酶非循环灌注+胶原酶循环灌注法能显著提高HSC获得率,且对细胞活力影响小,不降低细胞纯度,是一种高效的分离方法,有利于HSC相关肝脏疾病的生物学研究。     

α-Tocopherol is an effective Phase II enzyme inducer: protective effects on acrolein-induced oxidative stress and mitochondrial dysfunction in human retinal pigment epithelial cells

Vitamin E has long been identified as a major lipid-soluble chain-breaking antioxidant in mammals. α-Tocopherol is a vitamin E component and the major form in the human body. We propose that, besides its direct chain-breaking antioxidant activity, α-tocopherol may exert an indirect antioxidant activity by enhancing the cell's antioxidant system as a Phase II enzyme inducer. We investigated α-tocopherol's inducing effect on Phase II enzymes and its protective effect on acrolein-induced toxicity in a human retinal pigment epithelial (RPE) cell line, ARPE-19. Acrolein, a major component of cigarette smoke and also a product of lipid peroxidation, at 75 μmol/L over 24 h, caused significant loss of ARPE-19 cell viability, increased oxidative damage, decreased antioxidant defense, inactivation of the Keap1/Nrf2 pathway, and mitochondrial dysfunction. ARPE-19 cells have been used as a model of smoking- and age-related macular degeneration. Pretreatment with α-tocopherol activated the Keap1/Nrf2 pathway by increasing Nrf2 expression and inducing its translocation to the nucleus. Consequently, the expression and/or activity of the following Phase II enzymes increased: glutamate cysteine ligase, NAD(P)H:quinone oxidoreductase 1, heme-oxygenase 1, glutathione S-transferase and superoxide dismutase; total antioxidant capacity and glutathione also increased. This antioxidant defense enhancement protected ARPE-19 cells from an acrolein-induced decrease in cell viability, lowered reactive oxygen species and protein oxidation levels, and improved mitochondrial function. These results suggest that α-tocopherol protects ARPE-19 cells from acrolein-induced cellular toxicity, not only as a chain-breaking antioxidant, but also as a Phase II enzyme inducer.     

Epidermal restriction confers robustness to organ shapes

The shape of comparable tissues and organs is consistent among individuals of a given species, but how this consistency or robustness is achieved remains an open question. The interaction between morphogenetic factors determines organ formation and subsequent shaping, which is ultimately a mechanical process. Using a computational approach, we show that the epidermal layer is essential for the robustness of organ geometry control. Specifically, proper epidermal restriction allows organ asymmetry maintenance, and the tensile epidermal layer is sufficient to suppress local variability in growth, leading to shape robustness. The model explains the enhanced organ shape variations in epidermal mutant plants. In addition, differences in the patterns of epidermal restriction may underlie the initial establishment of organ asymmetry. Our results show that epidermal restriction can answer the longstanding question of how cellular growth noise is averaged to produce precise organ shapes, and the findings also shed light on organ asymmetry establishment.     

Natural variation in the promoter of OsHMA3 contributes to differential grain cadmium accumulation between Indica and Japonica rice

Rice is a major source of cadmium(Cd) intake for Asian people. Indica rice usually accumulates more Cd in shoots and grains than Japonica rice. However, underlying genetic bases for differential Cd accumulation between Indica and Japonica rice are still unknown. In this study, we cloned a quantitative trait locus(QTL) grain Cd concentration on chromosome 7(GCC7) responsible for differential grain Cd accumulation between two rice varieties by performing QTL analysis and map-based cloning. We found that the two GCC7 alleles, GCC7~(PA64s) and GCC7~(93-11), had different promoter activity of OsHMA3,leading to different OsHMA3 expression and different shoot and grain Cd concentrations. By analyzing the distribution of different haplotypes of GCC7 among diverse rice accessions, we discovered that the high and low Cd accumulation alleles, namely GCC7~(93-11) and GCC7~(PA64s), were preferentially distributed in Indica and Japonica rice,respectively. We further showed that the GCC7~(PA64s)allele can be used to replace the GCC7~(93-11) allele in the super cultivar 93-11 to reduce grain Cd concentration without adverse effect on agronomic traits. Our results thus reveal that the QTL GCC7 with sequence variation in the OsHMA3 promoter is an important determinant controlling differential grain Cd accumulation between Indica and Japonica rice.     

Split Nano luciferase complementation for probing protein‐protein interactions in plant cells

Deciphering protein‐protein interactions (PPIs) is fundamental for understanding signal transduction pathways in plants. The split firefly luciferase (Fluc) complementation (SLC) assay has been widely used for analyzing PPIs. However, concern has risen about the bulky halves of Fluc interfering with the functions of their fusion partners. Nano luciferase (Nluc) is the smallest substitute for Fluc with improved stability and luminescence. Here, we developed a dual‐use system enabling the detection of PPIs through the Nluc‐based SLC and co‐immunoprecipitation assays. This was realized by coexpression of two proteins under investigation in fusion with the HA‐ or FLAG‐tagged Nluc halves, respectively. We validated the robustness of this system by reproducing multiple previously documented PPIs in protoplasts or Agrobacterium‐transformed plants. We next applied this system to evaluate the homodimerization of Arabidopsis CERK1, a coreceptor of fungal elicitor chitin, and its heterodimerization with other homologs in the absence or presence of chitin. Moreover, split fragments of Nluc were fused to two cytosolic ends of Arabidopsis calcium channels CNGC2 and CNGC4 to help sense the allosteric change induced by the bacterial elicitor flg22. Collectively, these results demonstrate the usefulness of the Nluc‐based SLC assay for probing constitutive or inducible PPIs and protein allostery in plant cells.     

Cardiac telocytes exist in the adult Xenopus tropicalis heart

Recent research has revealed that cardiac telocytes (CTs) play an important role in cardiac physiopathology and the regeneration of injured myocardium. Recently, we reported that the adult Xenopus tropicalis heart can regenerate perfectly in a nearly scar‐free manner after injury via apical resection. However, whether telocytes exist in the X tropicalis heart and are affected in the regeneration of injured X tropicalis myocardium is still unknown. The present ultrastructural and immunofluorescent double staining results clearly showed that CTs exist in the X tropicalis myocardium. CTs in the X tropicalis myocardium were mainly twined around the surface of cardiomyocyte trabeculae and linked via nanocontacts between the ends of the telopodes, forming a three‐dimensional network. CTs might play a role in the regeneration of injured myocardium.