基于高通量测序的闽楠幼林根际土壤丛枝菌根真菌群落变化

【背景】闽楠是珍贵用材树种。阐明闽楠根际土壤微生物特征,对科学经营闽楠人工林有指导作用。【目的】明确闽楠人工林恢复过程中根际土壤丛枝菌根群落随林龄的变化特征。【方法】采用高通量Illumina MiSeq测序的方法,评估不同林龄闽楠幼林根际土壤丛枝菌根真菌(Arbuscular Mycorrhiza Fungi,AMF)群落的多样性和组成,揭示造林后闽楠根际土壤真菌群落对时间序列中土壤养分变化的响应特征。【结果】从3个林龄闽楠根际土壤中共得到342 555条有效序列,共得到253个AMF-OTU,分属于1门1纲5目9科14属。α多样性指数表明,丛枝菌根真菌群落的Chao1、Shannon指数随着林龄的增加而增加,但不同林龄间差异不显著。β多样性指数表明,在闽楠幼龄阶段,不同林龄间AMF群落组成差异明显。根据Bray-Curtis相异度分析阐明AMF群落组成的相似性与林龄相关。种水平物种丰度与土壤因子的相关性分析表明,影响AMF群落丰度的主要土壤因子是pH、全钾、硝态氮和铵态氮。铵态氮与优势AMF分子虚拟种Glomus-Franke-A1-VTX00076、Glomus-Franke-A1-VTX00269的丰度呈显著正相关。【结论】随着林龄的增加,闽楠幼龄根际土壤丛枝菌根真菌的种类组成发生了显著变化,影响AMF特性的主要土壤因子是pH、全钾、硝态氮和铵态氮。这些发现将有助于揭示闽楠幼林生态系统和土壤微生物多样性的相互关系和机制,为生物多样性-生态系统功能实验提供理论依据。     

Mechanism of p38 MAPK–induced EGFR endocytosis and its crosstalk with ligand-induced pathways

Ligand binding triggers clathrin-mediated and, at high ligand concentrations, clathrin-independent endocytosis of EGFR. Clathrin-mediated endocytosis (CME) of EGFR is also induced by stimuli activating p38 MAPK. Mechanisms of both ligand- and p38-induced endocytosis are not fully understood, and how these pathways intermingle when concurrently activated remains unknown. Here we dissect the mechanisms of p38-induced endocytosis using a pH-sensitive model of endogenous EGFR, which is extracellularly tagged with a fluorogen-activating protein, and propose a unifying model of the crosstalk between multiple EGFR endocytosis pathways. We found that a new locus of p38-dependent phosphorylation in EGFR is essential for the receptor dileucine motif interaction with the σ2 subunit of clathrin adaptor AP2 and concomitant receptor internalization. p38-dependent endocytosis of EGFR induced by cytokines was additive to CME induced by picomolar EGF concentrations but constrained to internalizing ligand-free EGFRs due to Grb2 recruitment by ligand-activated EGFRs. Nanomolar EGF concentrations rerouted EGFR from CME to clathrin-independent endocytosis, primarily by diminishing p38-dependent endocytosis.     

基于网络药理学与分子对接技术的清瘟护肺颗粒防治新型冠状病毒肺炎(COVID-19)的潜在药效物质研究

本文通过网络药理学和分子对接技术探讨清瘟护肺颗粒防治新型冠状病毒肺炎(COVID-19)的潜在药效物质。首先,通过TCMSP数据库,BATMAN-TCM数据库及TCMIP数据库检索清瘟护肺颗粒中十六味药的化学成分及作用靶点,利用GeneCards和OMIM数据库检索COVID-19的相关疾病靶点。然后,通过venny2.1.0获取清瘟护肺颗粒防治COVID-19的潜在靶点,利用R语言对潜在靶点进行GO功能和KEGG通路富集分析,并结合文献对富集所得通路进行分析。最后,利用Cytoscape3.7.1软件构建网络图,采用AutoDock4.2.1软件评价清瘟护肺颗粒中潜在药效成分和新型冠状病毒SARS-CoV-23CL水解酶、血管紧张素转化酶II(ACE2)和RNA依赖的RNA聚合酶(RdRp)的结合作用。网络药理学得到清瘟护肺颗粒防治COVID-19的473个活性成分和123个靶点,KEGG结果及文献分析预测到清瘟护肺颗粒可通过调控MAPK、小细胞肺癌、肺结核、PI3K-AKT等多条信号通路而发挥作用,分子对接结果显示清瘟护肺颗粒中潜在药效成分和SARS-CoV-23CL水解酶、ACE2及RdRp具有良好的亲和性。本研究较为全面揭示了清瘟护肺颗粒治疗COVID-19“多成分、多靶点、多通路”的特点,为深入探讨清瘟护肺颗粒治疗COVID-19的作用机制提供参考依据。     

麻杏石甘汤合玉屏风散对支原体肺炎患儿血清炎症因子、氧化应激及T淋巴细胞亚群的影响

目的:探讨麻杏石甘汤合玉屏风散对支原体肺炎患儿血清炎症因子、氧化应激及T淋巴细胞亚群的影响。方法:选取我院儿科门诊于2016年12月至2018年7月间收治的86例支原体肺炎患儿,按随机数字表法分为观察组(43例)和对照组(43例)。对照组采用常规治疗,观察组在对照组基础上联合使用麻杏石甘汤合玉屏风散治疗,两组均治疗14 d。比较两组患儿疗效及临床症状变化情况,检测并比较两组患儿血清炎症因子、氧化应激指标和T淋巴细胞亚群变化情况,观察两组患儿治疗过程中的不良反应发生情况。结果:观察组总有效率为93.02%(40/43),高于对照组的76.74%(33/43)(P<0.05)。观察组患儿体温恢复时间、啰音消失时间、咳嗽消失时间和X线检查恢复正常时间均明显短于对照组(P<0.05)。治疗14 d后,两组患儿血清白介素-2(IL-2)水平明显升高,而白介素-4(IL-4)、白介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)水平明显降低(P<0.05);且与对照组比较,观察组患儿治疗14 d后的血清IL-2水平明显较高,而IL-4、IL-6和TNF-α水平明显较低(P<0.05)。与治疗前比较,治疗5 d后、治疗14 d后,两组患儿血浆丙二醛(MDA)降低,超氧化物歧化酶(SOD)水平升高(P<0.05);与对照组比较,观察组治疗5 d后的血浆MDA明显较低,而SOD水平明显较高(P<0.05)。治疗14 d后,两组患儿CD3⁺、CD4⁺、CD4⁺/CD8⁺明显升高,且观察组高于对照组,而两组患儿CD8⁺明显降低,且观察组低于对照组(P<0.05)。两组不良反应比较差异无统计学意义(P>0.05)。结论:麻杏石甘汤合玉屏风散治疗支原体肺炎疗效显著,能够缓解临床症状、炎症反应,减轻患儿氧化应激状态,并可提高患儿免疫功能。     

益生菌联合早期肠内营养对合并应激性高血糖的重症脑卒中患者血糖调控及预后的影响

目的探讨益生菌联合早期肠内营养(EEN)对合并应激性高血糖的重症脑卒中患者血糖调控及预后的影响,为此类患者的治疗提供参考。方法选择2017年5月1日至2019年5月1日我院神经内科收治的合并应激性高血糖的重症脑卒中患者64例为研究对象,随机分为对照组和观察组,各32例。对照组患者在入院48 h内给予EEN,观察组患者在对照组基础上给予双歧杆菌乳杆菌三联活菌片鼻饲。比较两组患者治疗后血糖变异性、胰岛素使用强度、低血糖发生率、炎症反应指标水平、应激反应指标水平、胃肠道不良反应,5 d内肠内营养达标率、营养状态指标水平、医院获得性肺炎(HAP)发生率及病死率。结果治疗后,观察组患者血糖变异性较小,胰岛素使用强度降低,低血糖发生率降低,炎症反应指标、应激反应指标水平均低于对照组;胃肠道不良反应中腹泻发生率降低,肠内营养达标率升高,血清白蛋白、前白蛋白水平均高于对照组,医院获得性肺炎发生率降低。两组患者病死率差异无统计学意义(12.50%vs 18.75%;χ~2=0.474,P=0.491)。结论对于合并应激性高血糖的重症脑卒中患者,益生菌联合EEN有助于控制血糖稳定性,降低胰岛素使用强度及低血糖发生率,同时降低炎症及应激反应,提高患者肠内营养耐受性,改善患者营养状态,降低HAP发生率。     

A molecular phylogeny of the lizard genus Phymaturus (Squamata,Liolaemini): Implications for species diversity and historical biogeography of southern South America

The lizard genus Phymaturus is widely distributed in Argentina and along the eastern edge of Chile between 25° and 45° south. We sampled 27 of the 38 currently recognized species plus 22 candidate species using two mitochondrial genes (cytb and 12S), four protein coding nuclear genes and seven anonymous nuclear loci, and present the first comprehensive molecular phylogenetic hypothesis for the clade. We recovered two large clades (the palluma or northern group and patagonicus or southern group) previously recognized on the basis of morphological and mitochondrial sequence evidence, and compared results obtained from concatenated-gene analyses with results of a coalescent-based species-tree approach (BEST). With both methods we identified four main clades within the palluma group (mallimaccii, roigorum, verdugo, and vociferator) and five main clades within the patagonicus group (calcogaster, indistinctus, payuniae, somuncurensis, and spurcus). We found several instances of non-monophyly with cytb and cases of incongruence between mitochondrial vs nuclear data for which we discuss alternative hypotheses. Although with lower support values, combined BEST results are more congruent with concatenated nuclear data than with combined concatenated analyses, suggesting that BEST is less influenced by demographic processes than combined concatenated analyses. We discuss the taxonomic, biogeographic and conservation implications of these results and how the future integration of phylogeographic and morphological approaches will allow the further testing of demographic and biogeographic hypotheses.     

二烯丙基二硫对荷S180肉瘤小鼠的辐射增敏效应

研究大蒜素重要活性成分二烯丙基二硫(Diallyl disulfide,DADS)对荷S180肉瘤小鼠的辐射增敏效应。利用X射线对荷瘤小鼠全身辐照。测量肿瘤体积、重量;检测肿瘤组织中细胞凋亡及Bcl-2、Bax、caspase-3等凋亡因子的表达。同时测定了DADS对S180细胞增殖及细胞内活性氧(reactive oxygen species,ROS)的影响。结果显示:与对照组、单纯药物组及单纯辐照组相比,DADS联合辐照组小鼠的肿瘤体变小、重量减轻(P<0.01);肿瘤组织中TUNEL阳性细胞增多(P<0.01);Bax、caspase-3表达增强,而Bcl-2表达减弱。此外,DADS引起了S180细胞内大量ROS的产生。结果提示DADS对荷S180肉瘤小鼠具有辐射增敏效应,其机制与上调Bax、Caspase-3、下调Bcl-2表达及诱导肿瘤细胞产生ROS有关。     

Volumetric-modulated arc therapy with RapidArc®: An evaluation of treatment delivery efficiency

Aim/background

To evaluate how the use of volumetric-modulated arc therapy (VMAT) with RapidArc^® can improve treatment delivery efficiency based on the analysis of the beam-on times and monitor units (MU) needed to deliver therapy for multiple clinical applications in a large patient population.

Materials and methods

A total of 898 treatment courses were delivered in 745 patients treated from October 2008 to March 2013 using RapidArc® treatment plans generated in Eclipse™ TPS. All patients were treated with curative or palliative intent using different techniques including conventional fractionation (83%) and radiosurgery or SBRT (17%), depending on the clinical indications. Treatment delivery was evaluated based on measured beam-on time and recorded MU values delivered on a Varian Trilogy™ linear accelerator.

Results

For conventional fractionation treatments using RapidArc®, the delivery times ranged from 38 s to 4 min and 40 s (average 2 min and 6 s). For radiosurgical treatments the delivery times ranged from 1 min and 42 s to 9 min and 22 s (average 4 min and 4 s). The average number of MU per Gy was 301 for the entire group, with 285 for the conventional group and 317 for the radiosurgical group.

Conclusions

In this study with a large heterogeneous population, treatments using RapidArc® were delivered with substantially less beam-on time and fewer MUs than conventional fractionation. This was highly advantageous, increasing flexibility of the scheduling allowing treatment of radiosurgery patients during the regular daily work schedule. Additionally, reduction of leakage radiation dose was achieved.