遮阴对石笔木苗木生长和保护酶活性的影响

为探讨石笔木Tutcheria championi苗木对遮阴环境的适应性,以全光照(无遮阴覆盖)为对照,研究遮阴30%、50%和70%对2年生石笔木苗生长和生理特性的影响。结果表明,全光照下石笔木苗木生长较为健壮,其苗高、地径生长优于遮阴处理;全光照下石笔木总生物量、根生物量比以及根冠比显著大于遮阴处理(P<0.05);50%遮阴处理苗木叶片叶绿素含量显著高于全光照和70%遮阴处理(P<0.05),叶绿素a/b值在各处理间无显著差异。丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性在各处理间无显著差异(P>0.05);70%遮阴处理的苗木叶片过氧化氢酶(CAT)活性最高,显著高于全光照和50%遮阴。由此表明,充足的光照环境有利于石笔木苗木生长。     

鼎湖山森林群落演替之研究

鼎湖山森林群落在自然状态下遵循一定的客观规律向更优化的气候顶极群落演变。本文分析其1955年至1989年(35年)来的演替结果,总结出鼎湖山森林群落演替的进程和模式,进一步应用植物群落演替系统的线性模型和非线性模型对演替进程进行定量研究,并做出相应的演替进程的数量预测。     

Blockage of MDM2-mediated p53 ubiquitination by yuanhuacine restrains the carcinogenesis of prostate carcinoma cells by suppressing LncRNA LINC00665

Prostate cancer (PCa) is a challenging issue for men's health worldwide due to its uncontrolled proliferation and high metastatic potential. Increasing evidence has supported plant extracts and natural plant derivatives as promising antitumor therapy with less toxic side effects. Yuanhuacine is an active component isolated from Daphne genkwa and can effectively suppress the tumorigenesis of several cancers. However, its role in PCa remains unclear. In this study, yuanhuacine dose-dependently inhibited the proliferation and induced apoptosis of PCa cells. Moreover, yuanhuacine also restrained the invasion and migration of PCa cells. Mechanically, yuanhuacine decreased the ubiquitination and degradation of p53 protein, and ultimately increased p53 levels, which was regulated by inhibiting the phosphorylation and total protein levels of mouse double minute 2 (MDM2). Moreover, elevation of MDM2 reversed the suppressive efficacy of yuanhuacine in PCa cell viability, invasion, and migration. The network pharmacologic and bioinformatics analysis confirmed that MDM2 might be a common target of D. genkwa and LINC00665. Furthermore, yuanhuacine inhibited LINC00665 expression. Upregulation of LINC00665 reversed yuanhuacine-mediated inhibition in MDM2 protein expression and suppressed p53 levels by enhancing its ubiquitination in yuanhuacine-treated cells. Importantly, the inhibitory effects of yuanhuacine on cell viability and metastatic potential were offset after LINC00665 elevation. Together, the current findings highlight that yuanhuacine may possess tumor-suppressive efficacy by inhibiting LINC00665-mediated MDM2/p53 ubiquitination signaling. Therefore, this study indicates that yuanhuacine may be a promising candidate for the treatment of PCa.     

红细胞抗高血压因子降压作用的进一步研究

我们曾报道原发性高血压患者(EHS)红细胞抗高血压因子(AHF)具有缓慢而持久的降压作用。本工作表明,AHF对卒中易感型自发性高血压大鼠(SHRsp)还具有快速短暂的降压作用,注射AHF后10—30s,SHRsp收缩压从原水平的26.8±1.7kPa降至20.1±1.5kPa(P<0.001)。正常人和大鼠红细胞AHF的降压作用明显强于EHS和高血压大鼠AHF。此外我们还发现EHS血浆中存在升压物质。以上结果提示,AHF缺乏和升压物质含量相对较高可能是原发性高血压发病的一个重要原因。     

南极乔治王岛冰锥洞微生物培养探索

【目的】南极洲具备独特的环境和相对的生物地理隔离,南极洲各类生境中蕴藏了大量尚未培养和难培养的微生物,也是新颖微生物物种的重要来源之一。本研究以南极冰锥洞这类特殊生境为研究对象,通过培养条件的多样化提升南极微生物的培养率和多样性,揭示南极冰锥洞可培养微生物类群多样性,为该环境可培养微生物功能研究奠定基础,也为南极极端环境未培养微生物的培养方法提供借鉴。【方法】通过采用不同培养基添加复苏促进因子(resuscitation promoting factor, Rpf)的方式,提高南极柯林斯冰盖冰锥洞生境中微生物的可培养率,探究该生境中微生物的多样性。采用4种不同营养水平的培养基,平行添加Rpf进行菌株培养,经分离纯化与16S rRNA基因鉴定,分析冰锥洞可培养微生物的多样性及培养条件对多样性的影响。【结果】本研究共分离培养细菌407株,涵盖5个门、18个科、29个属,其中：放线菌门(Actinomycetota)为优势门,占72.73%;微杆菌科(Microbacteriaceae)为优势科,占69.78%;Lacisediminihabitans属为优势属,占45.70%。从培养基效果...     

论二次抽样以矫正多样性统计偏差的经典、发展与应用

稀疏标准化是定量古生物工作中矫正多样性统计偏差的常用方法。相比基于样本大小的传统稀疏化,基于采样充分度的改进能更忠实反映多样性信息。然而一些案例对于稀疏化的适用性不够重视,尤其是改进的方法鲜有国内文献介绍。本文阐述了稀疏化的原理,强调了应用的注意事项和改进方法的优势。稀疏化的原理是从大小不同的样本中二次抽样出彼此“公平”的子样本,以比较其分类单元丰富度。传统方法据样本大小衡量公平,改进的方法据采样充分度评估公平,要求子样本在群落中代表的个体频率总和相等。两种思路均可通过计算机模拟多次重复二次抽样或公式推导来计算,已有PAST和iNext等软件可以实现。采样是否充分代表了古生物群落是有效应用该方法的首要前提。     

基于Golden Gate技术的齐整小核菌转录单元高效组装系统

【目的】为齐整小核菌代谢工程研究建立高效的转录单元组装系统。【方法】通过应用Golden Gate技术,以mobius assembly为基础,分别设计并构建DNA元件标准化接口改造、单转录单元组装、应用质粒(多转录单元)组装等功能的载体,从而形成一套完整的多转录单元组装系统。【结果】构建了2个用于DNA元件标准化接口改造的Level 0载体,4个用于单转录单元组装的Level 1载体,4个用于应用质粒组装的Level 2载体和13个应用质粒组装的辅助质粒。然后应用此系统为齐整小核菌组装了若干经过标准化接口改造的DNA元件质粒、单转录单元质粒和硬葡聚糖相关基因的功能分析质粒。所构建的最终应用质粒可以同时适用于齐整小核菌的根癌农杆菌介导转化法、电穿孔转化法和原生质体转化法。【结论】此质粒系统具有强大的DNA设计、组装和容纳能力,为未来齐整小核菌代谢工程和功能基因组学研究提供了高效的质粒构建技术平台。     

Genomic insights into selection for heterozygous alleles and woody traits in Populus tomentosa

Heterozygous alleles are widespread in outcrossing and clonally propagated woody plants. The variation in heterozygosity that underlies population adaptive evolution and phenotypic variation, however, remains largely unknown. Here, we describe a de novo chromosome-level genome assembly of Populus tomentosa, an economic and ecologically important native tree in northern China. By resequencing 302 natural accessions, we determined that the South subpopulation (Pop_S) encompasses the ancestral strains of P. tomentosa, while the Northwest subpopulation (Pop_NW) and Northeast subpopulation (Pop_NE) experienced different selection pressures during population evolution, resulting in significant population differentiation and a decrease in the extent of heterozygosity. Analysis of heterozygous selective sweep regions (HSSR) suggested that selection for lower heterozygosity contributed to the local adaptation of P. tomentosa by dwindling gene expression and genetic load in the Pop_NW and Pop_NE subpopulations. Genome-wide association studies (GWAS) revealed that 88 single nucleotide polymorphisms (SNPs) within 63 genes are associated with nine wood composition traits. Among them, the selection for the homozygous AA allele in PtoARF8 is associated with reductions in cellulose and hemicellulose contents by attenuating PtoARF8 expression, and the increase in lignin content is attributable to the selection for decreases in exon heterozygosity in PtoLOX3 during adaptive evolution of natural populations. This study provides novel insights into allelic variations in heterozygosity associated with adaptive evolution of P. tomentosa in response to the local environment and identifies a series of key genes for wood component traits, thereby facilitating genomic-based breeding of important traits in perennial woody plants.     

白兰瓜子叶衰老过程中蔗糖酶同工酶的分离及其活性变化

利用DEAE—纤维素柱层析对白兰瓜子叶蔗糖酶同工酶进行了分离。发现细胞质可溶性部分含有4种蔗糖酶同工酶,其中3种为酸性蔗糖酶(Ⅰ、Ⅱ、Ⅲ),其活性最适pH分别为5.40、4.30和4.73;另外一种为碱性蔗糖酶,其最适pH为7.40。细胞壁盐溶性部分仅含1种酸性蔗糖酶,其最适pH亦为4.73。在白兰瓜子叶生长后期(7～11d),定位于细胞质的酸性蔗糖酶Ⅰ、Ⅱ和Ⅲ的活性略有升高;衰老发生后(17～23d)其活性显著下降;衰老后期碱性蔗糖酶活性消失。在子叶生长和衰老期间细胞壁酸性蔗糖酶活性则一直下降。