DNA sequence directs placement of histone cores on restriction fragments during nucleosome formation.

Restriction fragments, 203 and 144 base pairs in length, bearing the Escherichia coli lac control region have been reconstituted with the core histones from calf thymus to form nucleosomes. By several criteria the reconstituted nucleosomes are similar to native nucleosomes obtained by micrococcal nuclease digestion of calf thymus nuclei. However, sensitive nuclease digestion studies reveal subtle and important differences between native monosomes and the lac reconstitutes. Each reconstitute consists mainly of nucleosomes containing histone cores placed nonrandomly with respect to the DNA sequence. The shorter reconstitute forms asymmetric nucleosomes as evidenced by the DNase I digestion pattern. Exonuclease III digestion followed by 5'-end analysis of the larger reconstitute suggests that, of the many possible arrangements of histone core with DNA sequence, only two are highly favored.     

Single-cell transcriptomic atlas of primate cardiopulmonary aging

Aging is a major risk factor for many diseases,especially in highly prevalent cardiopulmonary comorbidities and infectious diseases including Coronavirus Diseas...     

植物光信号途径重要新调控因子TZP的研究进展

TZP(TANDEM ZINC-FINGER/PLUS3)是近年来鉴定到的一个光信号转导途径新组分,在光介导的植物生长发育过程中发挥重要调控作用。TZP不仅负调控蓝光信号途径,参与光敏色素B(phyB)介导的开花调控过程,还参与调控phyA在体内的蛋白质磷酸化。对TZP生化活性和作用机制的深入研究,不仅有助于进一步完善光信号调控网络,也可为设计和培育具有耐密理想株型及高光效作物新品种提供理论依据。该文系统总结了TZP在植物光信号途径中发挥的重要调控作用,并提出未来TZP功能研究的重要问题。     

英文教材Prescott's Microbiology的特点及其发展

Mc Graw-Hill Education出版的Prescott’s Microbiology从1990年第1版至今已有近26年,历经了两代作者更替,迄今已出版了10版。该书是在国际上使用较为广泛的微生物学教材,其内容和版本每三年更新一次,力求及时反映学科前沿水平的新知识、新技术。其内容丰富,精深广博;版式编排设计以读者(学生)需求为本;编排合理,结构灵活;图片精美,设计感强;配套教学资源系统完善。对该教材进行深入的研究,了解其体系、知识结构和内容等,对加强我国高校教材建设具有重要借鉴作用。     

东寨港红树林小型底栖动物丰度与Chla、有机质的相关性

于2015年4月(春季)、2015年6月(夏季)、2015年10月(秋季)、2016年1月(冬季),在海南东寨港红树林保护区潮间带进行多次采样,分选小型底栖动物,并测定沉积物中有机质和叶绿素a含量,分析不同季节东寨港红树林小型底栖动物丰度与有机质、Chla的相关性。研究结果,沉积物中小型底栖动物主要包括自由生活线虫、桡足类、涡虫、多毛类、寡毛类,线虫为优势类群;有机质含量为25.22%—93.41%,平均值为46.6%; Chla含量为0.188—6.303μg/g,平均值为1.731μg/g。相关性分析显示,春季小型底栖动物的丰度和Chla含量呈显著正相关(Pearson's r=0.684; P0.05),夏季小型底栖动物的丰度与有机质含量呈显著负相关(Pearson's r=-0.518; P0.05)。     

Caveolin-1 identified as a key mediator of acute lung injury using bioinformatics and functional research

Acute lung injury (ALI) is a potentially life-threatening, devastating disease with an extremely high rate of mortality. The underlying mechanism of ALI is currently unclear. In this study, we aimed to confirm the hub genes associated with ALI and explore their functions and molecular mechanisms using bioinformatics methods. Five microarray datasets available in GEO were used to perform Robust Rank Aggregation (RRA) to identify differentially expressed genes (DEGs) and the key genes were identified via the protein-protein interaction (PPI) network. Lipopolysaccharide intraperitoneal injection was administered to establish an ALI model. Overall, 40 robust DEGs, which are mainly involved in the inflammatory response, protein catabolic process, and NF-κB signaling pathway were identified. Among these DEGs, we identified two genes associated with ALI, of which the CAV-1/NF-κB axis was significantly upregulated in ALI, and was identified as one of the most effective targets for ALI prevention. Subsequently, the expression of CAV-1 was knocked down using AAV-shCAV-1 or CAV-1-siRNA to study its effect on the pathogenesis of ALI in vivo and in vitro. The results of this study indicated that CAV-1/NF-κB axis levels were elevated in vivo and in vitro, accompanied by an increase in lung inflammation and autophagy. The knockdown of CAV-1 may improve ALI. Mechanistically, inflammation was reduced mainly by decreasing the expression levels of CD3 and F4/80, and activating autophagy by inhibiting AKT/mTOR and promoting the AMPK signaling pathway. Taken together, this study provides crucial evidence that CAV-1 knockdown inhibits the occurrence of ALI, suggesting that the CAV-1/NF-κB axis may be a promising therapeutic target for ALI treatment.Subject terms: Cell signalling, Respiratory tract diseases     

森林转换对地表径流可溶性有机碳输出浓度和通量的影响

米槠次生林转换成米槠人工幼林和米槠人工促进天然更新幼林(以下简称"人促幼林")后,以这三种森林类型为研究对象,连续监测每次降雨后地表径流量及径流水中可溶性有机碳(DOC)的含量及通量,比较不同森林类型观测结果的差异,并分析降雨对实验结果的影响。结果表明:米槠人工幼林单次产流量是米槠次生林的1.5—19.0倍,观测期间总径流量为5.9倍;米槠人促幼林单次径流量和总径流量均与米槠次生林无显著差异(P0.05)。观测期间米槠次生林、人工幼林、人促幼林径流水DOC浓度值范围为5.9—18.4 mg/L,4.3—13.5 mg/L和3.2—9.9 mg/L,米槠次生林径流水浓度均值(12.6 mg/L)分别是米槠人促幼林(7.6 mg/L)和米槠人工幼林(5.3 mg/L)的1.6和2.4倍。回归分析表明,径流水中DOC浓度与降雨前土壤含水率呈显著相关;降雨前土壤含水率20.8%是一个临界值,含水率低于20.8%时,径流水DOC浓度与降雨前含水率呈显著正相关(P0.05);高于20.8%时,径流水DOC浓度与降雨前土壤含水率呈显著负相关(P0.05)。米槠人工幼林地表径流DOC输出通量是米槠次生林的0.7—5.4倍,观测期间总输出通量为2.1倍;米槠人促林DOC单次通量和观测期间总通量均与米槠次生林差异不显著(P0.05)。三种森林类型DOC输出通量均与降雨量呈显著相关(P0.05)。可见,米槠次生林转变成米槠人工幼林后DOC输出浓度降低,但径流量显著增加,导致DOC输出通量增加;而转变成米槠人促幼林后DOC输出浓度也降低,但径流量并未增加,因而并未增加DOC输出通量。     

不同农业土地利用方式和管理对土壤有机碳的影响 ——以北京市延庆盆地为例

自20世纪80年代以来,我国农业土地利用方式和农田管理发生了巨大变化,由此引起的土壤有机碳（SOC）含量、密度及其垂直分布发生了相应的变化,研究不同土地利用方式和管理对土壤有机碳的影响对于探讨农田生态系统的固碳作用具有重要的意义.以北京市延怀盆地为典型研究地区,选择6种农业土地利用和管理模式,共计42块样地,在1m深土体内分层采集197个土壤样品.研究结果表明：（1） 不同农业土地利用和管理方式对SOC含量的影响主要发生在0～25 cm土层中,剖面中SOC含量自上向下明显降低.（2） 通过对6种土地利用和管理方式下土壤SOC含量进行比较,结果发现果园和高投入的玉米地土壤在0～100 cm土层中SOC含量均较高,变化范围分别为4.16～10.00 g kg^-1和4.73～9.31 g kg^-1; 菜地土壤在0～40 cm土层中SOC含量较高,变化范围为6.42～9.67 g kg^-1;大豆地、中、低投入玉米地土壤在0～100 cm土层中SOC含量较低,变化范围分别为3.27～7.73 g kg^-1、3.14～8.33 g kg^-1和1.83～7.67 g kg^-1. （3） 不同农业土地利用方式对SOC密度影响的趋势与对SOC含量影响的趋势基本一致,在0～100 cm土壤中,SOC密度的顺序为果园＞菜地＞高投入玉米地＞中投入玉米地＞大豆地＞低投入玉米地,变化范围为4.15～8.22 kg m^-2.