土壤呼吸对降雨变化和氮沉降交互作用响应的研究进展

土壤呼吸作为陆地生态系统碳循环的关键过程,对大气CO₂浓度变化有直接影响。研究其如何响应降雨变化、氮沉降增加等全球变化因子,成为近年全球变化领域的热点与难点。与土壤呼吸响应降雨变化或氮沉降增加单个因子相比,研究土壤呼吸对这两个因子交互作用的响应更接近真实的自然环境,可更准确地预估未来土壤碳排放的变化趋势。目前,相关研究涉及全球不同的陆地生态系统,从土壤、微生物和植物层面对其响应机理进行揭示。本文从土壤呼吸及其组分、相关的土壤性质、微生物及植物因素方面,较全面地梳理了不同陆地生态系统土壤呼吸响应降雨变化和氮沉降增加交互作用的研究进展,指出了现有研究中的不足及今后需加强的研究方向,以期为进一步揭示土壤呼吸对降雨变化和氮沉降增加交互作用的响应规律及机制提供参考。     

COX-2 is required to mediate crosstalk of ROS-dependent activation of MAPK/NF-κB signaling with pro-inflammatory response and defense-related NO enhancement during challenge of macrophage-like cell line with Giardia duodenalis

Giardia duodenalis, the causative agent of giardiasis, is among the most important causes of waterborne diarrheal diseases around the world. Giardia infection may persist over extended periods with intestinal inflammation, although minimal. Cyclooxygenase (COX)-2 is well known as an important inducer of inflammatory response, while the role it played in noninvasive Giardia infection remains elusive. Here we investigated the regulatory function of COX-2 in Giardia-induced pro-inflammatory response and defense-related nitric oxide (NO) generation in macrophage-like cell line, and identified the potential regulators. We initially found that Giardia challenge induced up-regulation of IL-1β, IL-6, TNF-α, prostaglandin (PG) E2, and COX-2 in macrophages, and pretreatment of the cells with COX-2 inhibitor NS398 reduced expressions of those pro-inflammatory factors. It was also observed that COX-2 inhibition could attenuate the up-regulated NO release and inducible NO synthase (iNOS) expression induced by Giardia. We further confirmed that Giardia-induced COX-2 up-regulation was mediated by the phosphorylation of p38 and ERK1/2 MAPKs and NF-κB. In addition, inhibition of reactive oxygen species (ROS) by NAC was shown to repress Giardia-induced activation of MAPK/NF-κB signaling, up-regulation of COX-2 and iNOS, increased levels of PGE2 and NO release, and up-expressions of IL-1β, IL-6, and TNF-α. Collectively, in this study, we revealed a critical role of COX-2 in modulating pro-inflammatory response and defense-related NO production in Giardia-macrophage interactions, and this process was evident to be controlled by ROS-dependent activation of MAPK/NF-κB signaling. The results can deepen our knowledge of anti-Giardia inflammatory response and host defense mechanisms.     

Microbial nitrogen and phosphorus co-limitation across permafrost region

The status of plant and microbial nutrient limitation have profound impacts on ecosystem carbon cycle in permafrost areas, which store large amounts of carbon and experience pronounced climatic warming. Despite the long-term standing paradigm assumes that cold ecosystems primarily have nitrogen deficiency, large-scale empirical tests of microbial nutrient limitation are lacking. Here we assessed the potential microbial nutrient limitation across the Tibetan alpine permafrost region, using the combination of enzymatic and elemental stoichiometry, genes abundance and fertilization method. In contrast with the traditional view, the four independent approaches congruently detected widespread microbial nitrogen and phosphorus co-limitation in both the surface soil and deep permafrost deposits, with stronger limitation in the topsoil. Further analysis revealed that soil resources stoichiometry and microbial community composition were the two best predictors of the magnitude of microbial nutrient limitation. High ratio of available soil carbon to nutrient and low fungal/bacterial ratio corresponded to strong microbial nutrient limitation. These findings suggest that warming-induced enhancement in soil nutrient availability could stimulate microbial activity, and probably amplify soil carbon losses from permafrost areas.     

Eriodictyol regulated ferroptosis,mitochondrial dysfunction,and cell viability via Nrf2/HO-1/NQO1 signaling pathway in ovarian cancer cells

This study aimed to investigate the antitumor effect and the underlying molecular mechanism of eriodictyol on ovarian cancer cells. CaoV3 and A2780 were exposed to eriodictyol at different concentrations of 0−800 μM. Cell apoptosis and viability were determined by TdT-mediated dUTP Nick-End Labeling (TUNEL) assay and Cell Counting Kit-8 (CCK-8) assay, respectively. Mitochondrial membrane potential was evaluated by flow cytometers with a JC-1 detection kit. Fe²⁺ content was evaluated using an iron assay kit. The section of tumor tissues was observed using hematoxylin-eosin (H&E) staining and nuclear factor erythroid 2-related factor 2 (Nrf2) expression was detected by immunohistochemistry (IHC) staining. Eriodictyol suppressed cell viability and induced cell apoptosis of CaoV3 and A2780 cells. Half maximal inhibitory concentration (IC₅₀) value of CaoV3 at 24 and 48 h was (229.74 ± 5.13) μM and (38.44 ± 4.68) μM, and IC₅₀ value of A2780 at 24 and 48 h was (248.32 ± 2.54) μM and (64.28 ± 3.19) μM. Fe²⁺ content and reactive oxygen species production were increased and protein levels of SLC7A11 and GPX4 were decreased by eriodictyol. Besides, eriodictyol reduced the ratio of JC-1 fluorescence ratio, glutathione and malondialdehyde contents but elevated Cytochrome C level. Nrf2 phosphorylation were obviously downregulated by eriodictyol. Finally, eriodictyol suppressed tumor growth, aggravated mitochondrial dysfunction and downregulated Nrf2 expression in tumor tissue in mice. Eriodictyol regulated ferroptosis, mitochondrial dysfunction and cell viability via Nrf2/HO-1/NQO1 signaling pathway in ovarian cancer.     

Biphenyl Derivatives from the Aerial Parts of Oenanthe javanica and Their COX‐2 Inhibitory Activities

Four new biphenyl derivatives ( 1 – 4 ), along with six known biphenyl derivatives ( 5 – 10 ) were isolated and elucidated by their detailed analyses of spectroscopic data and references from the aerial parts of Oenanthe javanica for the first time. Compounds ( 1 – 10 ) were assayed for their activities about the inhibition of COX‐2 enzyme in vitro for the first time. Compounds 1 , 2 , 4 , and 6 showed inhibitory activities against COX‐2 with IC₅₀ values ranging from 22.18±0.29 to 108.54±0.42 μm .     

Calculation of an Adequate Intake (AI) Value and Safe Range of Selenium (Se) for Chinese Infants 0–3 Months Old Based on Se Concentration in the Milk of Lactating Chinese Women with Optimal Se Intake

Biological Trace Element Research - The required selenium intake for optimal health in Chinese residents was published in 2014. However, the adequate intake (AI) value for Chinese infants...     

高通量流式荧光微球悬液芯片检测乙肝病毒基因分型

目的:建立HBV基因分型高通量液相芯片检测技术,并探讨其应用价值.方法:对GenBank中收录的明确分型的HBV基因序列进行分析,选择preS2-S区设计引物和A、B、C和D型特异性探针.与荧光编码微球偶联的特异型探针与一条引物生物素标记的PCR产物直接杂交反应,然后结合亲和素标记的藻红蛋白,用流式检测仪(Bio-Plex 200)检测荧光信号.检测182份阳性乙肝患者血清DNA,其中35份样品检测结果与测序法比较.用B、C型质粒DNA倍比稀释及混合样品检测灵敏度来评估该方法.结果:建立了HBV基因分型的快速高通量液相芯片检测方法.182份患者血清检测结果为:B型占24.2％ (44/182),C型占71.4％(130/182),D型为6.6 ％(12/182),BC混合型4.4％(8/182).其中35份样本与测序法比较,除3份混合型测序法未检出外,其它32例结果均相同本方法的灵敏度检测下线为1×103 copies/mL.结论:应用悬液芯片技术进行乙肝病毒的基因分型分析,具有较好的特异性和较高的灵敏度,并有简便、灵活和高通量等优势.该检测系统不仅在科研中有广泛的前景,也有望成为临床推广的多重分子诊断和基因分型的新方法.     

Movement herkogamy in Kosteletzkya virginica: Effect on reproductive success and contribution to pollen receipt and reproductive assurance

Herkogamy may act as a mechanism to reduce interference between the reproductive functions of female and male organs, but too great a distance between stigmas and anthers may also decrease the outcross pollen transfer and male and female fitness. Our goal was to quantify the effect of movement herkogamy in Kosteletzkya virginica on reproductive success and its contribution to pollen receipt and reproductive assurance. Field investigations and hand-pollination experiments were performed to test: (1) the relationship between herkogamy before curvature of un-pollinated lobes and reproductive success under pollinator exclusion; (2) the contribution of movement herkogamy to pollen receipt; and (3) the relationship between pollen load and seed set. We noted that variation in herkogamy before curvature of un-pollinated lobes did not affect the outcome of autogamous self-pollination measured by fruit set and mean number of seeds per fruit. Under natural conditions, 39% of pollen grains deposited per flower were from autogamous self-pollination via movement herkogamy resulting in contact between anthers and stigmas. The relationship between the amount of pollen grains and the number of seeds per capsule was highly significant. Flowers producing four or five seeds received more pollen grains than those producing only one seed. Our data provides experimental evidence that movement herkogamy, which decreases the separation between anthers and stigmas and results in delayed self-pollination, contributes to pollen receipt and further enhances seed set when pollinators are scarce or absent.     

Complete Genome Sequence of a Recombinant Nephropathogenic Infectious Bronchitis Virus Strain in China

Recently, nephropathogenic infectious bronchitis virus (IBV) outbreaks have occurred in commercial broiler flocks and have been associated with a high incidence and morbidity in China. The CK/CH/Zhejiang/06/10 strain (IBV-YX10) was isolated from a 12-day-old broiler chicken in a flock of chickens with swollen speckled kidneys and distended ureters filled with uric acid in China in 2010. Here we reported the complete genomic sequence of the IBV-YX10 which was a natural recombinant nephropathogenic infectious bronchitis virus strain. These findings will contribute additional insights into the molecular characteristics of evolving IBV genomes and the need for effective control of IBV in China.     

Early Altered Resting-State Functional Connectivity Predicts the Severity of Post-Traumatic Stress Disorder Symptoms in Acutely Traumatized Subjects

The goal of this study was to investigate the relationship between resting-state functional connectivity and the severity of post-traumatic stress disorder (PTSD) symptoms in 15 people who developed PTSD following recent trauma. Fifteen participants who experienced acute traumatic events underwent a 7.3-min resting functional magnetic resonance imaging scan within 2 days post-event. All the patients were diagnosed with PTSD within 1 to 6 months after trauma. Brain areas in which activity was correlated with that of the posterior cingulate cortex (PCC) were assessed. To assess the relationship between the severity of PTSD symptoms and PCC connectivity, contrast images representing areas positively correlated with the PCC were correlated with the subject’s Clinician-Administered PTSD Scale scores (CAPS) when they were diagnosed. Furthermore, the PCC, medial prefrontal cortex and bilateral amygdala were selected to assess the correlation of the strength of functional connectivity with the CAPS. Resting state connectivity with the PCC was negatively correlated with CAPS scores in the left superior temporal gyrus and right hippocampus/amygdala. Furthermore, the strength of connectivity between the PCC and bilateral amygdala, and even between the bilateral amygdala could predict the severity of PTSD symptoms later. These results suggest that early altered resting-state functional connectivity of the PCC with the left superior temporal gyrus, right hippocampus and amygdala could predict the severity of the disease and may be a major risk factor that predisposes patients to develop PTSD.