无距虾脊兰果实发育及其解剖学特征

以授粉后无距虾脊兰不同发育阶段的蒴果为材料,对果实生长动态进行研究,并用石蜡切片法进行果实结构研究。观察结果表明：无距虾脊兰果实授粉至授粉后40 d生长速度最快。果实由3心皮组成,横切面为6瓣,3瓣有胎座,3瓣无胎座,开裂后6瓣于顶端连接。发育的过程中,果皮细胞层数及果实内外表皮细胞体积不变,果实直径的增加主要来自于细胞平周分裂和中果皮细胞体积的增大。果实成熟时只有少数细胞有细胞壁增厚现象,开裂线的前体细胞细胞壁发生木质化并向不同方向收缩导致果实的开裂。     

Response of CH4 and N2O Emissions and Wheat Yields to Tillage Method Changes in the North China Plain

The objective of this study was to quantify soil methane (CH₄) and nitrous oxide (N₂O) emissions when converting from minimum and no-tillage systems to subsoiling (tilled soil to a depth of 40 cm to 45 cm) in the North China Plain. The relationships between CH₄ and N₂O flux and soil temperature, moisture, NH₄ ⁺-N, organic carbon (SOC) and pH were investigated over 18 months using a split-plot design. The soil absorption of CH₄ appeared to increase after conversion from no-tillage (NT) to subsoiling (NTS), from harrow tillage (HT) to subsoiling (HTS) and from rotary tillage (RT) to subsoiling (RTS). N₂O emissions also increased after conversion. Furthermore, after conversion to subsoiling, the combined global warming potential (GWP) of CH₄ and N₂O increased by approximately 0.05 kg CO₂ ha⁻¹ for HTS, 0.02 kg CO₂ ha⁻¹ for RTS and 0.23 kg CO₂ ha⁻¹ for NTS. Soil temperature, moisture, SOC, NH₄ ⁺-N and pH also changed after conversion to subsoiling. These changes were correlated with CH₄ uptake and N₂O emissions. However, there was no significant correlation between N₂O emissions and soil temperature in this study. The grain yields of wheat improved after conversion to subsoiling. Under HTS, RTS and NTS, the average grain yield was elevated by approximately 42.5%, 27.8% and 60.3% respectively. Our findings indicate that RTS and HTS would be ideal rotation tillage systems to balance GWP decreases and grain yield improvements in the North China Plain region.     

互花米草入侵影响下闽江河口湿地土壤有效硅的时空变化特征

2016年1—12月,选择闽江河口鳝鱼滩的短叶茳芏湿地、互花米草湿地以及二者的交错带湿地为研究对象,采用定位研究方法探讨了互花米草入侵影响下湿地土壤有效硅含量的时空变化特征。结果表明:互花米草入侵影响下3块湿地土壤有效硅含量随时间推移整体呈波动上升趋势;互花米草入侵显著提高了鳝鱼滩湿地30—60 cm土层土壤有效硅含量(P0.01),与短叶茳芏湿地相比,交错带湿地和互花米草湿地30—60 cm土层土壤有效硅含量分别增加了8.56%和19.97%,逐步线性回归分析表明土温和电导是影响其变化的重要因素(P0.01)。研究互花米草入侵影响下湿地土壤有效硅含量的变化特征,对于揭示湿地生态系统生源要素硅生物地球化学循环过程以及互花米草入侵及其扩张机制具有重要意义。     

全球转基因大豆专利信息分析与技术展望

转基因大豆作为目前转基因作物推广种植面积最广的作物,在保障人类油料与饲料供给上发挥着重要作用。基于智慧芽数据库(PatSnap)对欧盟、美国及中国等国家地区1985~2016年收录的全球转基因大豆技术领域专利文献进行统计分析,得出全球转基因大豆专利信息的总体发展趋势、研发热点及技术分布与格局,并对比分析了我国转基因大豆研发的竞争力,对未来转基因大豆的产业发展提出了展望。     

Enhanced chemiluminescence enzyme‐linked immunoassay for the determination of DNA methyltransferase 1 in human serum

The occurrence of many diseases is closely related to the high expression of DNA methyltransferase 1 (DNMT1). However, most studies are focused on the detection of DNMT1 activity, a few are concerned with the detection of DNMT1 content. In this study, we developed a simple and highly sensitive chemiluminescence (CL) assay for the detection of DNMT1 content. In this method, anti‐DNMT1 monoclonal antibody was coated on a polystyrene microplate to capture DNMT1. Then anti‐DNMT1 polyclonal antibody and goat anti‐rabbit immunoglobulin G with horseradish peroxidase (IgG‐HRP) were respectively added to combine with captured DNMT1 to form a sandwich structure. Finally, the HRP could catalyze CL substrate and achieve CL signal response. Based on this novel sensitive strategy, the recovery percents were in the ranges from 71.5% to 91.0%. The precision of intra‐assays and inter‐assays were 5.45%–11.29% and 7.03%–11.25%, respectively. The method was successfully applied for the determination of DNMT1 in human serum. The detection results of serum samples showed that the proposed assay had a high correlation with enzyme‐linked immunosorbent assay (ELISA) kit. Compared with the ELISA kit (limit of detection = 0.1 ng/mL), the method has a lower limit of detection of 0.042 ng/mL. Therefore, our method has the potential for the detection of DNMT1 content in clinical diagnosis.     

Comprehensive metabolomic,proteomic and physiological analyses of grain yield reduction in rice under abrupt drought–flood alternation stress

Abrupt drought–flood alternation (T1) is a meteorological disaster that frequently occurs during summer in southern China and the Yangtze river basin, often causing a significant loss of rice production. In this study, the response mechanism of yield decline under abrupt drought–flood alternation stress at the panicle differentiation stage was analyzed by looking at the metabolome, proteome as well as yield and physiological and biochemical indexes. The results showed that drought and flood stress caused a decrease in the yield of rice at the panicle differentiation stage, and abrupt drought–flood alternation stress created a synergistic effect for the reduction of yield. The main reason for the decrease of yield per plant under abrupt drought–flood alternation was the decrease of seed setting rate. Compared with CK0 (no drought and no flood), the net photosynthetic rate and soluble sugar content of T1 decreased significantly and its hydrogen peroxidase, superoxide dismutase, peroxidase activity increased significantly. The identified differential metabolites and differentially expressed proteins indicated that photosynthesis metabolism, energy metabolism pathway and reactive oxygen species response have changed strongly under abrupt drought–flood alteration stress, which are factors that leads to the rice grain yield reduction.     

The Adverse Effects of Se Toxicity on Inflammatory and Immune Responses in Chicken Spleens

Selenium (Se) is an essential trace element, but excessive intake of Se could induce Se poisoning, and result in various health problems. NF-κB regulated many molecules of the immune response and the inflammatory response, and Th1/Th2 balance played a key in the regulation of immune response. The aim of this study is to investigate the role of NF-κB pathway and Th1/Th2 imbalance in the adverse influence of Se poisoning on chicken spleens. In the current study, 90 chickens were randomly divided into two groups (n?=?45 per group). The chickens were maintained either on a basal diet (the control group) containing 0.2 mg/kg Se or a high supplemented diet (the Se group) containing 15 mg/kg Se for 45 days. Then, we observed the pathohistology of spleen cells and detected NO content, iNOS activity, and the expression of NF-κB, iNOS, COX-2, PTGE, IL-6, TNF-α, Foxp3, IL-4, and IFN-γ in chicken spleens. In chicken spleens of the Se group, the result showed typical characteristics of inflammation: the content of NO and the activity of iNOS were increased, and the expression of NF-κB, iNOS, COX-2, PTGE, IL-6, TNF-α, and IL-4 was enhanced and that of Foxp3 and IFN-γ was decreased. Our study showed that Se toxicity could promote inflammation via NF-κB pathway, impairing the immune function, and changing Th1/Th2 balance in the chicken spleens.     

核酸适配体在感染性疾病诊治中的研究进展

临床上,感染性疾病由于诊断不明或诊断时间较长导致严重后果的情况并不罕见。近年来,由于新型病原体感染报道层出不穷,现有病原体出现耐药也十分普遍,导致感染性疾病的诊断和治疗仍是临床上亟待解决的难题。核酸适配体是通过体外反复筛选或指数富集配体系统进化(systematic evolution of ligands by exponential enrichment,SELEX)技术筛选出来的一类具有特异性识别能力的寡核苷酸序列,具有靶向结合目标分子的能力,可用于病原体检测和新型治疗性药物的开发。适配体已在感染性疾病诊治中显现良好的应用前景,进一步推进相关研究有望为感染性疾病的诊治提供新的途径。     

Diversity and conservation of Chinese wild begonias

Begonia, one of the most diverse plant taxa and the fifth or sixth largest angiosperm genus, consists of over 1800 accepted species. The number of species recognized within this genus has greatly increased over the past 20 years, rising from 80 to 200 species in China alone. Based on recent field surveys, the number of begonia species in China is predicted to be between 250 and 300. Given the large number of begonia species that still remain to be described, further taxonomical work is urgently required. This is especially true for Chinese Begonia, in which there is a huge diversity of habitat, habit, plant size, leaf type, flower and fruit morphology, and most species are narrowly distributed in isolated habitats that are subject to negative disturbances from climate change, as well as agricultural and industrial activities. Although the conservation status for the majority of species has been evaluated using the standards of the International Union for Conservation of Nature, the results don't represent the truth in many species, and also about 11.5% of which are data-absent. In addition, illegal collection and over-harvesting of wild begonias for ornamental or medicinal use has increased due to the rapid development of internet commerce. Far more often than predicted, these species should be categorized as rare and endangered and require immediate protection. Ex situ conservation of Chinese begonias started in 1995 and over 60% of the total species have been so far introduced into cultivation by several major botanical gardens in China. However, only few research institutions, limited funds and human resources have been involved in Begonia conservation; moreover, no project has conducted reintroduction. Therefore, more conservation-based work remains to be done. Improved conservation of Chinese begonias in the future depends on further field survey, an improved understanding of population diversity, and integrative approaches, including in situ and ex situ conservation, seed banking, and plant reintroduction. Speciestargeted conservation zones should be established for endangered species excluded from the existing nature reserves. Additionally, laws pertaining to plant protection should be extended to prevent the illegal collection and transaction of wild plants, particularly for those species with unique habitats and small populations.     

FOXO1 promotes wound healing through the up-regulation of TGF-β1 and prevention of oxidative stress

Keratinocyte mobilization is a critical aspect of wound re-epithelialization, but the mechanisms that control its precise regulation remain poorly understood. We set out to test the hypothesis that forkhead box O1 (FOXO1) has a negative effect on healing because of its capacity to inhibit proliferation and promote apoptosis. Contrary to expectations, FOXO1 is required for keratinocyte transition to a wound-healing phenotype that involves increased migration and up-regulation of transforming growth factor β1 (TGF-β1) and its downstream targets, integrin-α3 and -β6 and MMP-3 and -9. Furthermore, we show that FOXO1 functions in keratinocytes to reduce oxidative stress, which is necessary to maintain cell migration and prevent cell death in a TGF-β1–independent manner. Thus, our studies identify a novel function for FOXO1 in coordinating the response of keratinocytes to wounding through up-regulation of TGF-β1 and other factors needed for keratinocyte migration and protection against oxidative stress, which together promote migration and decrease apoptosis.