小黑杨花粉植株H_1株系间变异及其选择利用的研究

小黑杨(Populus xiaohei T.S.Hwang ex C.Wang et Tung)花药离体培养获得单倍体植株,经14年的生长观察,发现花粉植株间表现出明显分离。选出19个株系进行田间比较试验,统计分析,结果发现材积生长差异显著。可从中选出优良株系加以利用,并提出杨树单倍体育种程序。     

MiR-181a-5p promotes neural stem cell proliferation and enhances the learning and memory of aged mice

Hippocampal neural stem cell (NSC) proliferation is known to decline with age, which is closely linked to learning and memory impairments. In the current study, we found that the expression level of miR-181a-5p was decreased in the hippocampal NSCs of aged mice and that exogenous overexpression of miR-181a-5p promoted NSC proliferation without affecting NSC differentiation into neurons and astrocytes. The mechanistic study revealed that phosphatase and tensin homolog (PTEN), a negative regulator of the AKT signaling pathway, was the target of miR-181a-5p and knockdown of PTEN could rescue the impairment of NSC proliferation caused by low miR-181a-5p levels. Moreover, overexpression of miR-181a-5p in the dentate gyrus enhanced the proliferation of NSCs and ameliorated learning and memory impairments in aged mice. Taken together, our findings indicated that miR-181a-5p played a functional role in NSC proliferation and aging-related, hippocampus-dependent learning and memory impairments.     

Silencing of RHEB inhibits cell proliferation and promotes apoptosis in colorectal cancer cells via inhibition of the mTOR signaling pathway

Colorectal cancer (CRC) is commonly known as one of the most prominent reasons for cancer-related death in China. Ras homolog enriched in brain (RHEB) and the mammalian target activity of rapamycin (mTOR) signaling pathway were found correlated with CRC, but their specific interaction in CRC was still to be investigated. Therefore, we explored whether RHEB gene silencing affected the cell proliferation, differentiation, and apoptosis by directly targeting the mTOR signaling pathway in cells previously harvested from CRC patients. A microarray analysis was subsequently conducted to investigate the relationship between RHEB and mTOR. Eighty-three adjacent normal tissues and CRC tissues were selected. Immunohistochemistry was carried out to detect the positive expression rates of RHEB and Ki-67 in the CRC tissues. Cells were then transfected with different siRNAs to investigate the potential effects RHEB would have on CRC progression. The expressions of RHEB, 4EBP1, ribosomal protein S6 kinase (p70S6K), proliferating cell nuclear antigen (PCNA), B cell lymphoma 2 (bcl-2), and bcl-2-associated X protein (bax) were determined and then the cell cycle, cell proliferation, and apoptotic rate were also measured. We identified RHEB and mTOR as upregulated genes in CRC. Cells treated with RHEB silencing showed a decreased extent of mTOR, p70S6K, 4EBP1 phosphorylation and expression of RHEB, Ki-67, mTOR, p70S6K, 4EBP1, bcl-2, and PCNA as well as decreased activity of cell proliferation and differentiation; although, the expression of bax was evidently higher. Collectively, our data propose the idea that RHEB gene silencing might repress cell proliferation and differentiation while accelerating apoptosis via inactivating the mTOR signaling pathway.     

HSCCC分离纯化未成熟罗汉果皂苷类化合物

为建立高速逆流色谱分离未成熟罗汉果中皂苷类化合物的方法,该研究将罗汉果粗提物先经过大孔树脂富集皂苷类化合物,再采用高速逆流色谱分离罗汉果皂苷。结果表明:以氯仿-甲醇-正丁醇-水(5∶6∶1∶4,v/v/v/v)作为两相溶剂系统,上相为固定相,下相为流动相,在主机转速为860 r·min~(-1),流速为2.5 mL·min~(-1),检测波长为203 nm的条件下,一次性制备得到4个化合物,即11-O-罗汉果皂苷Ⅱ(Ⅰ)、罗汉果皂苷ⅡE(Ⅱ)、11-O-罗汉果皂苷Ⅲ(Ⅲ)和罗汉果皂苷Ⅲ(Ⅳ),经高效液相色谱检测纯度分别为95.5%、98.2%、80.1%和97.6%。该方法实现了未成熟罗汉果皂苷快速有效的分离,具有样品回收率高、损失少、避免样品失活等优点,提高了分离效率。该研究结果为更多的罗汉果皂苷化合物的分离纯化奠定了基础,补充与优化了罗汉果皂苷类化合物的分离方法。     

基于转录组的楠木MYB转录因子的挖掘及分析

楠木(Phoebe zhennan)为樟科常绿乔木,是国家二级重点保护树种。楠木生长缓慢,木材形成所需周期较长,其原因有待进一步深入分析。近年来转录因子已成为植物分子生物学研究的热点,高通量测序技术的应用和发展促进了转录因子的挖掘和深入分析。该研究基于我国特有濒危树种楠木的转录组数据,通过与拟南芥基因组MYB转录因子进行对比,对楠木MYB转录因子进行挖掘和生物信息学分析,并结合功能预测和不同组织表达对其进行深入分析。结果表明:从楠木转录组数据中,共挖掘出82个MYB转录因子,这82个MYB转录因子蛋白质所含氨基酸数目为50~1 121个、分子量为5.907~123.64 k Da,整体表现为亲水性不稳定蛋白,以α-螺旋和无规则卷曲为主要二级结构元件。序列比对和进化树分析表明,楠木MYB转录因子的结构域有高度保守性,含有[W]-X(19)-[W]-X(19)结构;82个Pz MYB可分为22类,参与生长发育、次生代谢、逆境响应等过程,与功能预测分析结果相一致。同时,在楠木茎和叶中,差异表达Pz MYB数目为18个,其中上调10个、下调8个。该研究结果不仅对楠木MYB转录因子的挖掘和功能分析以及分子生物学研究奠定了基础,而且还对其遗传改良和分子育种具有参考价值。     

中国特有植物篦子三尖杉的生物学特性及其保护

本文综述了我国特有植物篦子三尖杉（ＣｅｐｈａｌｏｔａｘｕｓｏｌｉｖｅｒｉＭａｓｔ．）的生物学特性,包括其外部形态特征、苗端、幼茎、叶、树皮、木材的内部结构、生殖生物学特性、花粉形态、化学成分、地理分布和分类地位等,最后初步分析了篦子三尖杉的濒危机制,并提出了几项保护措施。     

N6 ‐methyladenosine‐modified circRNA RERE modulates osteoarthritis by regulating β‐catenin ubiquitination and degradation

ObjectivesN⁶‐methyladenosine (m6A) is one of the most abundant internal RNA modifications. We investigated the role of m6A‐modified circRERE in osteoarthritis (OA) and its mechanism.Materials and MethodsCircRERE and IRF2BPL were screened by microarrays. The role of m6A‐modification in circRERE was examined by methylated RNA precipitation and morpholino oligo (MOs) treatment. The axis of circRERE/miR‐195‐5p/IRF2BPL/β‐catenin was determined using flow cytometry, western blotting and immunofluorescence in human chondrocytes (HCs) and corroborated using a mouse model of destabilization of medial meniscus (DMM) with intra‐articular (IA) injection of adeno‐associated viruses (AAV).ResultsCircRERE was decreased in OA cartilage and chondrocytes compared with control. CircRERE downregulation was likely attributed to its increased m6A modification prone to endoribonucleolytic cleavage by YTHDF2‐HRSP12‐RNase P/MRP in OA chondrocytes. MOs transfection targeting HRSP12 binding motifs in circRERE partially reversed decreased circRERE expression and increased apoptosis in HCs treated with IL‐1β for 6 h. CircRERE exerted chondroprotective effects by targeting miR‐195‐5p/IRF2BPL, thus regulating the ubiquitination and degradation of β‐catenin. CircRere (mouse homologue) overexpression by IA‐injection of AAV‐circRere into mice attenuated the severity of DMM‐induced OA, whereas AAV‐miR‐195a‐5p or AAV‐sh‐Irf2bpl reduced the protective effects. The detrimental effects of AAV‐sh‐Irf2bpl on DMM‐induced OA were substantially counteracted by ICG‐001, an inhibitor of β‐catenin.ConclusionsOur study is a proof‐of‐concept demonstration for targeting m6A‐modified circRERE and its target miR‐195‐5p/IRF2BPL/β‐catenin as potential therapeutic strategies for OA treatment.

Liu et al. demonstrate that circRERE expression is downregulated in human osteoarthritis (OA) cartilage and chondrocytes, and circRERE downregulation is likely attributed to its increased m6A modification prone to endoribonucleolytic cleavage by YTHDF2‐HRSP12‐RNase P/MRP. Mechanistically, circRERE downregulation leads to aberrant β‐catenin ubiquitin and degradation by targeting miR‐195‐5p/IRF2BPL during OA pathogenesis.     

铜陵淡水豚国家级自然保护区半自然水域鱼类群落结构研究

2021年5月采用多网目复合刺网和抛网相结合的方法,对铜陵淡水豚国家级自然保护区半自然水域夹江鱼类群落进行了调查。共采集到鱼类30种,隶属于5目7科27属。相对重要性指数显示鲢（Hypophthalmichthys molitrix）、贝氏?（Hemiculter bleekeri）、似鳊（Pseudobrama simoni）、团头鲂（Megalobrama amblycephala）、鳊（Parabramis pekinensis）和翘嘴鲌（Culter alburnus）为群落优势种。与长江江豚（Neophocaena asiaeorientalis）争夺饵料资源的凶猛性鱼类比例达到2.4%,体长分布显示夹江中存在大量长江江豚无法摄食的大个体鱼类（17.5%）。夹江鱼类群落的Shannon-Weiner指数、Simpson指数、Margalef指数和Pielou均匀度指数依次分别为1.955~2.181,0.794~0.820,2.952~3.856和0.705~0.730。空间生态位宽度指数、平均拥挤度和生态位重叠指数表明,夹江优势种鱼类可能存在较为激烈的种间竞争。建议清理鳡（Elopichthys bambusa）、翘嘴鲌、达氏鲌（Culter dabryi）和乌鳢（Channa argus）等凶猛性鱼类及其他与长江江豚争夺饵料的鱼类,及时捕捞全长超过25 cm的鱼类,补充投放鲢、似鳊、银鲴（Xenocypris argentea）等长江江豚偏好摄食鱼类。