乙型肝炎肝硬化腹水合并自发性细菌性腹膜炎患者肠道菌群特征

初步分析乙型肝炎肝硬化腹水合并自发性细菌性腹膜炎（SBP）患者肠道菌群特征,为该类患者的治疗提供参考。

选取我院符合纳入标准的乙型肝炎肝硬化腹水患者45例为研究对象,其中24例合并SBP的患者为SBP组、21例未合并SBP的患者为NSBP组,另选同期20例健康人为HC组。应用16S rDNA测序技术检测患者肠道菌群,并使用生物信息学方法分析各组对象肠道菌群变化。

SBP组、NSBP组及HC组相比,其肠道菌群的物种多样性及丰富度差异均无统计学意义（均P＜0.05）。PCoA分析显示,NSBP组与HC组患者肠道菌群结构相似,SBP组与其他两组相比菌群结构较为不同。与NSBP组相比,SBP组患者肠道菌群中变形菌门（Proteobacteria,5.45% vs 13.50%,U = 161.000,P = 0.038）、软壁菌门（Tenericutes,0.019% vs 0.073%,U = 162.000,P = 0.035）、埃希—志贺菌属（Escherichia-Shigella,0.24% vs 9.53%,U = 103.000,P = 0.001）、柠檬酸杆菌属（Citrobacter,LDA＞2）等丰度均增加;酸杆菌门（Acidobacteria,0.026% vs 0.015%,U = 152.000,P = 0.023）、罗氏菌属（Roseburia,2.55% vs 2.00%,U = 152.000,P = 0.023）、粪球菌属（Coprococcus,LDA＞2）等丰度下降。

乙型肝炎肝硬化腹水的发生发展与肠道菌群密切相关,在SBP患者肠道菌群中发现潜在病原体数量显著增加,并伴随有益细菌数量的减少。

     

北京地区热力景观格局及典型城市景观的热环境效应

城市热环境是城市生态环境中的一个重要指标,将景观生态学理论融入到热环境研究中,尝试探讨北京地区热力景观格局及城市公园、道路景观的热环境效应。地表温度反演是分析热力景观格局及典型城市景观热环境效应的前提,论文以北京地区为例,首先利用两景ASTER影像数据采用TES算法定量反演地表温度。通过半变异函数分析地表温度空间异质性,确定最大采样尺度,然后在景观统计软件Fragstats中,计算不同粒度下的景观格局指数,分析热力景观格局及其尺度效应。通过景观斑块特征分析和缓冲区分析,探讨公园景观斑块、道路景观廊道特征的热环境效应。总体上公园景观对应的平均温度随着公园面积、边界长度的增加而减小,随着公园周长面积比增大而增大;随着距离公园渐远,地表温度升高,且升温趋势变缓。随着道路密度增加,道路平均温度显著升高,标准差显著降低,道路密度等级与道路平均温度的相关系数达到0.8021;随着距离道路中心线距离增加,缓冲区内的平均温度略有下降,但变化微弱。因此,应充分重视公园景观在缓解城市热环境方面的作用,合理布局城市道路。     

LGR5 regulates osteogenic differentiation of human thoracic ligamentum flavum cells by Wnt signalling pathway

Thoracic ossification of the ligamentum flavum (TOLF) is ectopic ossification of the spinal ligaments. Histologically, the development of TOLF can be described as the process of endochondral ossification. However, the underlying aetiology has not been completely clarified. In this investigation, the gene expression profile associated with leucine‐rich repeat‐containing G‐protein‐coupled receptors (LGR) and Wnt signalling pathway in the thoracic ligamentum flavum cells (TLFCs) of different ossification stages was analysed via RNA sequencing. We further confirmed the significant differences in the related gene expression profile by Gene Ontology (GO) enrichment analysis. LGR5 was first identified in primary human TLFCs during osteogenic differentiation. To evaluate the effect of LGR5 on osteogenic differentiation, LGR5 has been knocked down and overexpressed in human TLFCs. We observed that the knockdown of LGR5 inhibited the activity of Wnt signalling and attenuated the potential osteogenic differentiation of TLFCs, while overexpression of LGR5 activated the Wnt signalling pathway and increased osteogenic differentiation. Our results provide important evidence for the potent positive mediatory effects of LGR5 on osteogenesis by enhancing the Wnt signalling pathway in TOLF.     

Distinct basolateral amygdala excitatory inputs mediate the somatosensory and aversive-affective components of pain

Pain is a multidimensional perception that includes unpleasant somatosensory and affective experiences; however, the underlying neural circuits that mediate different components of pain remain elusive. Although hyperactivity of basolateral amygdala glutamatergic (BLA^Glu) neurons is required for the somatosensory and emotional processing of pain, the precise excitatory inputs to BLA^Glu neurons and their roles in mediating different aspects of pain are unclear. Here, we identified two discrete glutamatergic neuronal circuits in male mice: a projection from the insular cortex glutamatergic (IC^Glu) to BLA^Glu neurons, which modulates both the somatosensory and affective components of pain, and a projection from the mediodorsal thalamic nucleus (MD^Glu) to BLA^Glu neurons, which modulates only the aversive-affective component of pain. Using whole-cell recording and fiber photometry, we found that neurons within the IC→BLA and MD→BLA pathways were activated in mice upon inflammatory pain induced by injection of complete Freund’s adjuvant (CFA) into their paws. Optical inhibition of the IC^Glu→BLA pathway increased the nociceptive threshold and induced behavioral place preference in CFA mice. In contrast, optical inhibition of the MD^Glu→BLA pathway did not affect the nociceptive threshold but still induced place preference in CFA mice. In normal mice, optical activation of the IC^Glu→BLA pathway decreased the nociceptive threshold and induced place aversion, while optical activation of the MD^Glu→BLA pathway only evoked aversion. Taken together, our results demonstrate that discrete IC^Glu→BLA and MD^Glu→BLA pathways are involved in modulating different components of pain, provide insights into its circuit basis, and better our understanding of pain perception.     

SARS-CoV-2 envelope protein causes acute respiratory distress syndrome (ARDS)-like pathological damages and constitutes an antiviral target

Cytokine storm and multi-organ failure are the main causes of SARS-CoV-2-related death. However, the origin of excessive damages caused by SARS-CoV-2 remains largely unknown. Here we show that the SARS-CoV-2 envelope (2-E) protein alone is able to cause acute respiratory distress syndrome (ARDS)-like damages in vitro and in vivo. 2-E proteins were found to form a type of pH-sensitive cation channels in bilayer lipid membranes. As observed in SARS-CoV-2-infected cells, heterologous expression of 2-E channels induced rapid cell death in various susceptible cell types and robust secretion of cytokines and chemokines in macrophages. Intravenous administration of purified 2-E protein into mice caused ARDS-like pathological damages in lung and spleen. A dominant negative mutation lowering 2-E channel activity attenuated cell death and SARS-CoV-2 production. Newly identified channel inhibitors exhibited potent anti-SARS-CoV-2 activity and excellent cell protective activity in vitro and these activities were positively correlated with inhibition of 2-E channel. Importantly, prophylactic and therapeutic administration of the channel inhibitor effectively reduced both the viral load and secretion of inflammation cytokines in lungs of SARS-CoV-2-infected transgenic mice expressing human angiotensin-converting enzyme 2 (hACE-2). Our study supports that 2-E is a promising drug target against SARS-CoV-2.Subject terms: Cell death, Molecular biology     

红松阔叶混交林林隙土壤水分分布格局的地统计学分析

以小兴安岭原始红松阔叶混交林林隙为研究对象,采用网格法布点,通过对生长季内林隙各样点土壤含水量的连续观测,利用基本统计学和地统计学的方法分析并揭示了林隙土壤含水量的时空分布格局,旨在为红松阔叶混交林的可持续经营提供基础数据和理论参考。结果表明:林隙土壤含水量不仅存在明显的空间异质性,而且空间异质性的强度、尺度和空间结构组成随时间而改变。浅层土壤水分空间异质性大于深层,林隙0—7.6 cm、0—12 cm和0—20 cm土壤含水量大小顺序均为9月>7月>8月>6月。林隙、郁闭林分和空旷地土壤含水量大小顺序均为0—7.6 cm>0—12 cm>0—20 cm。生长季内6月土壤含水量不同空间样点极差最大,各月变异都属于中等变异程度;基台值和变程大小顺序同样为0—7.6 cm>0—12 cm>0—20 cm;林隙月平均土壤含水量斑块连接度高,形状复杂,0—7.6 cm、0—12 cm和0—20 cm平均土壤含水量最大值均分布在林隙中心及其附近,最小值分布位置不固定;生长季内土壤含水量及其变化程度均为空旷地最大,林隙次之,郁闭林分最小。     

植物核DNA含量在全球尺度上的纬度变异式样及其气候适应意义——以菊科植物为例

核DNA含量是重要的生物学概念,涉及DNA C-值和基因组大小。前人有关植物核DNA含量在纬度梯度上的变异规律存在着矛盾的报道,而且多数将核DNA含量与纬度、海拔、气候等因素之间的关系描述成线性关系。核DNA含量是否具有环境适应上的意义,也还存在争议。先前有关核DNA含量与环境因素间关系的矛盾性报道可能与取样过小、地理范围过窄、研究对象遗传背景差异过大有关。如果对一个遗传背景相近的类群在全球范围内进行取样,核DNA含量会呈现有规律的纬度梯度变化,可能与大的气候因素之间存在非线性关系。菊科(Asteraceae)是被子植物的最大科,是一个广泛认可的自然分类群。为揭示全球空间尺度上植物核DNA含量在纬度梯度上的变异规律,以及这种变异是否具有环境适应意义,以菊科为对象开展了核DNA含量与纬度、生物气候因素关系的统计分析。从"植物DNA C-值数据库"检索到822种菊科植物的核DNA含量数据;在全球范围内,沿经度方向上设立10条样带,每条样带横跨15个经度,每条样带又均分成22个样块,每个样块纵跨7.5个纬度;其次,从"世界气候数据网站"下载1950—2000年时间段14个生物气候因子数据,应用Arc GIS 9.3获得每个样块14个生物气候因子的平均值;根据"全球生物多样性信息网站"记录,计算每个样块菊科植物平均的核DNA含量数据。为避免气候变量之间的多重共线性对数据分析的影响,应用主成分分析对数据进行了降维,发现最冷季度平均温度、最干季度雨量分别是第一、二主成分上荷载最大的因子,去除与它们相关性在-0.7至+0.7之间的其他气候因子后获得了最冷季度平均温度、最干季度雨量和最湿月份雨量三个变量用于进一步数据分析。结果发现,菊科植物在全球10个样带上的核DNA含量与纬度关系密切,与最冷季度平均温度、最干季度雨量和最湿月份雨量呈现极显著的单峰型的非线性关系,可以用二项式进行拟合。因此,全球空间尺度上植物核DNA含量沿着纬度梯度有规律性的非线性变化,这种变化具有很强的气候适应意义。