钙调蛋白及其突变体与电压门控钠离子通道1.2异亮氨酸-谷氨酰胺基序的结合作用

目的: 探讨在不同钙离子浓度下电压门控钠离子通道（Na_V）1.2与钙调蛋白（CaM）的结合,并分析CaM的钙离子结合位点突变后与Na_V1.2结合能力的变化。方法: 应用PCR技术构建Na_V1.2蛋白片段异亮氨酸-谷胺酰胺（IQ）基序的cDNA,采用QIAGEN点突变技术构建CaM突变体（CaM₁₂、CaM₃₄、CaM₁₂₃₄）,应用牵出（pull-down）试验技术检测有钙（100 nmol/L钙离子浓度）和无钙条件下Na_V1.2 IQ与CaM及其突变体（CaM₁₂、CaM₃₄、CaM₁₂₃₄）的结合情况。结果: CaM与Na_V1.2 IQ在无钙和有钙情况下均可互相结合,而单独重组谷胱甘肽-S-转移酶（GST）不具有与CaM结合的能力。无钙条件下CaM与Na_V1.2 IQ的结合量大于有钙条件下两者的结合量（P < 0.05）;无钙条件下,CaM野生型与Na_V1.2 IQ结合量大于CaM突变体与Na_V1.2 IQ的结合量,其中CaM₁₂₃₄的结合能力在三个突变体中最弱（P < 0.05）。结论: CaM及其突变体对Na_V1.2 IQ的结合具有钙离子依赖性,这一CaM调控Na_V1.2新机制为离子通道疾病研究提供了一定依据。     

Novel coding,translation, and gene expression of a replicating covalently closed circular RNA of 220 nt

The highly structured (64% GC) covalently closed circular (CCC) RNA (220 nt) of the virusoid associated with rice yellow mottle virus codes for a 16-kDa highly basic protein using novel modalities for coding, translation, and gene expression. This CCC RNA is the smallest among all known viroids and virusoids and the only one that codes proteins. Its sequence possesses an internal ribosome entry site and is directly translated through two (or three) completely overlapping ORFs (shifting to a new reading frame at the end of each round). The initiation and termination codons overlap UGAUGA (underline highlights the initiation codon AUG within the combined initiation-termination sequence). Termination codons can be ignored to obtain larger read-through proteins. This circular RNA with no noncoding sequences is a unique natural supercompact “nanogenome.”Viroids and virusoids (viroid-like satellite RNAs) are typically small (220–450 nt) covalently closed circular (CCC) RNAs with no coding capacity (i.e., no genetic information) (1–3) and are the smallest replicating circular RNA pathogens (3, 4). Because of their circular nature, they usually replicate through a rolling circle model to produce larger concatemers (4, 5) which are then processed into monomeric forms with a self-splicing hammerhead ribozyme (virusoids and viroids in the Avsunviroidae family) (6, 7) or by cellular enzymes (8). We have previously reported (9) the characterization and nucleotide sequence of the smallest circular virusoid (220 nt), that of the rice yellow mottle virus (sobemovirus) (RYMV). Like other known virusoids, the small circular satellite of RYMV (scRYMV) depends on a helper virus RYMV for replication and packaging (9, 10).In silico translation of scRYMV revealed the presence of an unusual ORF capable of initiating translation from the AUG in the sequence UGAUGA of the 220-nt circular RNA by internal ribosome binding site (IRBS). As 220 is not an integer multiple of 3, after the first round of translation, the same circular sequence (or possibly the linear head-to-tail concatemers generated in vivo during rolling-circle replication) would be read in a different frame register. After the second round of translation, termination at the same initiation–termination sequence UGAUGA would result in the production of a highly basic 16-kDa protein with the N- and C-terminal halves of the protein encoded by the same 220-nt sequence but read in two distinct, totally overlapping frames. This virusoid could also suppress the leaky tandem termination codons (UGAUGA) to read the same sequence in a third frame and produce a new (18 kDa) read-through protein with an 18-aa C-terminal extension ended by a UAG codon. However, even the latter UAG termination codon may occasionally be ignored to generate longer proteins.In this report, we present evidence demonstrating that the putative ORF(s) deduced from the 220-nt circular RNA sequence as described above are indeed operational.Although this scRYMV RNA is classified as a virusoid, we report here that this virusoid is the only one so far found to encode for a protein. Modalities of initiation of translation (e.g., overlapped initiation and termination codons), the distinct N- and C-terminal halves of the 16-kDa protein translated from the same 220-nt circular sequence and the generation of read-through proteins were examined. We discuss the evolutionary implications of the genetic information and biological functions densely packed into a 220-nt nanogenome.     

Repeat associated small RNAs vary among parents and following hybridization in maize

Small RNAs (sRNAs) are hypothesized to contribute to hybrid vigor because they maintain genome integrity, contribute to genetic diversity, and control gene expression. We used Illumina sequencing to assess how sRNA populations vary between two maize inbred lines (B73 and Mo17) and their hybrid. We sampled sRNAs from the seedling shoot apex and the developing ear, two rapidly growing tissues that program the greater growth of maize hybrids. We found that parental differences in siRNAs primarily originate from repeat regions. Although the maize genome contains greater number and complexity of repeats compared with Arabidopsis or rice, we confirmed that, like these simpler plant genomes, 24-nt siRNAs whose abundance differs between maize parents also show a trend of down-regulation following hybridization. Surprisingly, hybrid vigor is fully maintained when 24-nt siRNAs are globally reduced by mutation of the RNA-dependent RNA polymerase 2 encoded by modifier of paramutation1 (mop1). We also discovered that 21-22-nt siRNAs derived from a number of distinct retrotransposon families differentially accumulate between B73 and Mo17 as well as their hybrid. Thus, maize possesses a unique source of genetic variation for regulating transposons and genes at a genomic scale, which may contribute to its high degree of observed heterosis.     

环状非编码RNA在眼部疾病中表达研究进展

环状非编码RNA（circRNA）是指一类不具有5’末端帽子和3’末端poly（A）尾巴的一类非编码RNA,其通过共价键形成环形结构,它们可以通过几种不同的机制调节蛋白质的编码。越来越多的研究发现,circRNA在细胞增殖、分化、凋亡、血管生成、免疫调节等多种细胞功能中发挥一定的作用,从而导致多种疾病（如恶性肿瘤、炎症性疾病、神经系统疾病等）的发生。本文综述了circRNA在眼科疾病中的潜在作用和可能机制,以期能够为相关眼科疾病的早期诊断和不同阶段的治疗提供新的思路。     

The long-non-coding RNA NEAT1 is a novel target for Alzheimer’s disease progression via miR-124/BACE1 axis

ABSTRACT

Objectives: Long-non-coding RNAs (lncRNAs) have been involved in central nervous system recently. A number of studies have reported that lncRNA NEAT1 exerts critical roles in neurodegenerative disorder. Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) has been reported to exert function in the accumulation of amyloid-β (Aβ). Moreover, BACE1 acts as a target of miR-124 in the progression of AD. So far, the biological role and underlying mechanisms of NEAT1 and miR-124 in AD remains elusive.

Methods: The relative NEAT1 and miR-124 expression was examined by qRT-PCR in the tissues and cells line of AD. Cell apoptosis was examined by FACS. Luciferase reporter assay was performed to verify that miR-124 is a direct target of NEAT1, and BACE1 is a downstream target of miR-124. qRT-PCR and western blot analysis were also performed to determinate the BACE1 and the phosphorylation of tau protein.

Results: NEAT1 was notably up-regulated and miR-124 was remarkably down-regulated in AD mouse model. Knockdown of NEAT1 or overexpression of miR-124 showed the protective effects on cellular AD model induced by Aβ. Moreover, miR-124 expression could be up- and down-regulated by suppression or overexpression of NEAT1, respectively. In addition, the expression of BACE1 was the potential functional target of miR-124. These findings suggested that NEAT1 might play a vital role in the development of AD by regulating miR-124/BACE1 axis.

Discussion: The present study showed that NEAT1 worked as a regulating factor to promote the development of AD via modulating miR-124/BACE1 axis, which might be considered as a novel target in AD treatment.     

长链非编码RNA 在胰腺癌中的研究进展

长链非编码RNA(lncRNAs)是一类转录本长度超过200nt、不具备蛋白编码功能的RNA分子。LncRNAs能够在表观遗传、基因转录水平以及转录后水平等不同层面发挥作用。此外,新近发现的微小RNA、环状RNA等可与lnc RNAs交互作用,参与恶性肿瘤的发生与发展过程。近年来,研究发现大量的lncRNAs异常表达于胰腺癌组织和细胞中,在胰腺癌的发生发展中也起着重要作用。因此,笔者就多种异常表达的lncRNAs在胰腺癌中的作用及机制进行综述。     

Nano in nano: Biosynthesized gold and iron nanoclusters cargo neoplastic exosomes for cancer status biomarking

Timely detection is crucial for successful treatment of cancer. The current study describes a new approach that involves utilization of the tumor cell environment for bioimaging with in-situ biosynthesized nanoscale gold and iron probes and subsequent dissemination of Au-Fe nanoclusters from cargo exosomes within the circulatory system. We have isolated the Au-Fe cargo exosomes from the blood of the treated murine models after in situ biosyntheses from their respective pre-ionic solutions (HAuCl₄, FeCl₂), whereas Na₂SeO₃ supplementation added into Au lethal effect. The microarray data of various differentially expressed genes revealed the up-regulated tumor ablation and metal binding genes in SGC-7901 cell lines after treatment with Au-Fe-Se triplet ionic solution. The isolation of Au-Fe nanoclusters cargo exosomes (nano in nano) after secretion from deeply seated tumors may help in early diagnosis and reveal the tumor ablation status during and after the relevant treatment like radio-chemo therapies et al.     

T形钩预劈核联合囊膜精细处理技术在高度近视合并白内障术中的应用

目的:探讨T形钩预劈核联合囊膜精细处理技术治疗高度近视合并白内障的临床疗效。方法:选取2016-03/2019-02期间在河北省眼科医院就诊的合并高度近视的白内障患者56例80眼,随机进行分组,A组患者40眼行白内障超声乳化联合T形钩预劈核及囊膜精细处理手术。B组患者40眼行单纯白内障超声乳化术。比较两组患者术中超声累积释放能量,术后随访6mo以上,观察最佳矫正视力(BCVA)、前囊口收缩变化量、后囊膜混浊程度、人工晶状体居中性及手术并发症情况。结果:A组患者术中超声累积释放能量少于B组(12.23±3.61 vs 20.46±4.61,P<0.01)。术后6mo,A组患者BCVA优于B组(Z=5.328,P=0.002),前囊口收缩变化量、人工晶状体偏中心量(0.18±0.14、0.02±0.007mm)小于B组(0.82±0.23、0.65±0.240mm)(均P<0.05),且A组患者均可见后囊膜中央3mm大小圆孔,视轴区保持透明,而B组患者中13眼(32%)出现后囊膜中央区混浊。A组患者未出现术中后囊膜意外破裂及术后视网膜脱离情况,B组患者术中发生后囊膜意外破裂2眼(5%),术后视网膜脱离1眼(2%)。结论:采用T形钩预劈核联合囊膜精细处理技术治疗合并高度近视的白内障可减少术中超声能量的使用,降低后囊膜破裂的风险,有效避免后发性白内障的发生,可以取得满意的临床疗效。     

二氢菲类化合物赫尔西酚的手性异构体研究

目的研究中华石仙桃(Pholidota chinensis Lindl)全草中分离得到的二氢菲类化合物赫尔西酚(hircinol)的立体结构并进行手性异构体的分离。方法采用多种柱色谱法进行分离纯化,并根据比旋光度和圆二色谱数据进行构型确定。利用手性色谱柱对分离得到的赫尔西酚进行手性异构体的拆分。结果与结论得到赫尔西酚A、赫尔西酚B两种手性异构体,两种异构体比例为78.9∶22.1,两种异构体的比旋光度分别为+25.4°和-25.4°。本文首次报道赫尔西酚是具有旋光性的对映体,经圆二色谱(CD)测定和解析证明赫尔西酚A为S构型、赫尔西酚B为R构型。     

Recycled Fibers for Sustainable Hybrid Fiber Cement Based Material: A Review

Reinforcing fibers have been widely used to improve physical and mechanical properties of cement-based materials. Most fiber reinforced composites (FRC) involve the use of a single type of fiber to improve cement properties, such as strength or ductility. To additionally improve other parameters, hybridization is required. Another key challenge, in the construction industry, is the implementation of green and sustainable strategies based on reducing raw materials consumption, designing novel structures with enhanced properties and low weight, and developing low environmental impact processes. Different recycled fibers have been used as raw materials to promote circular economy processes and new business opportunities in the cement-based sector. The valuable use of recycled fibers in hybrid FRC has already been proven and they improve both product quality and sustainability, but the generated knowledge is fragmented. This is the first review analyzing the use of recycled fibers in hybrid FRC and the hybridization effect on mechanical properties and workability of FRC. The paper compiles the best results and the optimal combinations of recycled fibers for hybrid FRC to identify key insights and gaps that may define future research to open new application fields for recycled hybrid FRC.