Hepato-specific microRNA-122 facilitates accumulation of newly synthesized miRNA through regulating PRKRA

microRNAs (miRNAs) are a versatile class of non-coding RNAs involved in regulation of various biological processes. miRNA-122 (miR-122) is specifically and abundantly expressed in human liver. In this study, we employed 3'-end biotinylated synthetic miR-122 to identify its targets based on affinity purification. Quantitative RT-PCR analysis of the affinity purified RNAs demonstrated a specific enrichment of several known miR-122 targets such as CAT-1 (also called SLC7A1), ADAM17 and BCL-w. Using microarray analysis of affinity purified RNAs, we also discovered many candidate target genes of miR-122. Among these candidates, we confirmed that protein kinase, interferon-inducible double-stranded RNA-dependent activator (PRKRA), a Dicer-interacting protein, is a direct target gene of miR-122. miRNA quantitative-RT-PCR results indicated that miR-122 and small interfering RNA against PRKRA may facilitate the accumulation of newly synthesized miRNAs but did not detectably affect endogenous miRNAs levels. Our findings will lead to further understanding of multiple functions of this hepato-specific miRNA. We conclude that miR-122 could repress PRKRA expression and facilitate accumulation of newly synthesized miRNAs.     

Inhibition of Monoamine Oxidase by 7-Chloro-4-Nitrobenzofurazan

7-Chloro-4-nitrobenzofurazan (NBD-Cl) is a potent inhibitor of both types of monoamine oxidase (MAO). NBD-Cl competitively inhibited the oxidative deamination of kynuramine catalyzed by human placenta MAO-A, the oxidative deamination of benzylamine catalyzed by bovine liver MAO-B, the oxidative deamination of serotonin catalyzed by rat brain MAO-A, and the oxidative deamination of phenylethylamine catalyzed by rat brain MAO-B. In addition, a time-dependent inactivation of MAOs by NBD-Cl has been demonstrated upon incubation of the enzyme preparations with NBD-Cl at pH 9, but not at pH 7.5. The time-dependent inhibition of MAO by NBD-Cl could be prevented by the addition of 4-nitrophenyl azide, an active site-directed label of MAO, during incubation of the enzyme with NBD-Cl. On the basis of these findings, it is suggested that at pH 9, NBD-Cl modifies one (or more) essential lysine residue(s) in the active sites of the two types of MAO.     

nit-2, the major nitrogen regulatory gene of Neurospora crassa, encodes a protein with a putative zinc finger DNA-binding domain.

The nitrogen regulatory circuit of Neurospora crassa consists of a set of unlinked structural genes which specify various nitrogen catabolic enzymes plus control genes and metabolic effectors which regulate their expression. The positive-acting nit-2 regulatory gene is required to turn on the expression of the nitrogen catabolic enzymes during conditions of nitrogen limitation. The complete nucleotide sequence of the nit-2 gene was determined. The nit-2 mRNA is 4.3 kilobases long and has a long nontranslated sequence at both its 5' and 3' ends. The nit-2 gene nucleotide sequence can be translated to yield a protein containing 1,036 amino acid residues with a molecular weight of approximately 110,000. Deletion analyses demonstrated that approximately 21% of the NIT2 protein at its carboxy terminus can be removed without loss of function. The nit-2 protein contains a single putative Cys2/Cys2 zinc finger domain which appears to function in DNA binding and which has striking homology to a mammalian trans-acting factor, GF-1.     

抗阿特拉津转基因大豆植株后代的遗传分析

本试验用阿特拉津溶液涂抹、荧光诱导动力学检测、分子杂交等方法对抗阿特拉津转基因大豆植株的后代进行了鉴定,在第二代及第三代中检测到了抗性基因的存在,表明从龙葵中得到的此抗阿特拉津 psbA 基因不仅能导人大豆叶绿体基因组中获得表达,而且可以遗传到后代。     

Fasting up‐regulates ferroportin 1 expression via a Ghrelin/GHSR/MAPK signaling pathway

The significant positive correlation between ghrelin and iron and hepcidin levels in the plasma of children with iron deficiency anemia prompted us to hypothesize that ghrelin may affect iron metabolism. Here, we investigated the effects of fasting or ghrelin on the expression of hepcidin, ferroportin 1 (Fpn1), transferrin receptor 1 (TfR1), ferritin light chain (Ft‐L) proteins, and ghrelin, and also hormone secretagogue receptor 1 alpha (GHSR1α) and ghrelin O‐acyltransferase (GOAT) mRNAs in the spleen and/or macrophage. We demonstrated that fasting induces a significant increase in the expression of ghrelin, GHSR1α, GOAT, and hepcidin mRNAs, as well as Ft‐L and Fpn1 but not TfR1 proteins in the spleens of mice in vivo. Similar to the effects of fasting on the spleen, ghrelin induced a significant increase in the expression of Ft‐L and Fpn1 but not TfR1 proteins in macrophages in vitro. In addition, ghrelin was found to induce a significant enhancement in phosphorylation of ERK as well as translocation of pERK from the cytosol to nuclei. Furthermore, the increased pERK and Fpn1 induced by ghrelin was demonstrated to be preventable by pre‐treatment with either GHSR1α antagonist or pERK inhibitor. Our findings support the hypothesis that fasting upregulates Fpn1 expression, probably via a ghrelin/GHSR/MAPK signaling pathway.     

Analysis of Evolutionarily Independent Protein-RNA Complexes Yields a Criterion to Evaluate the Relevance of Prebiotic Scenarios

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Quantitative analysis of mitral valve morphology in atrial functional mitral regurgitation using real-time 3-dimensional echocardiography atrial functional mitral regurgitation

Background

Atrial fibrillation (AF) can result in atrial functional mitral regurgitation (MR), but the mechanism remains controversial. Few data about the relationship between the 3-dimensional morphology of the MV and the degree of MR in AF exist.

Methods

Real-time 3-dimensional transesophageal echocardiography (3D-TEE) of the MV was acquired in 168 patients with AF (57.7% persistent AF), including 25 (14.9%) patients with moderate to severe MR (the MR+ group) and 25 patients without AF as controls. The 3-dimensional geometry of the MV apparatus was acquired using dedicated quantification software.

Results

Compared with the group of patients with no or mild MR (the MR- group) and the controls, the MR+ group had a larger left atrium (LA), a more dilated mitral annulus (MA), a reduced annular height to commissural width ratio (AHCWR), indicating flattening of the annular saddle shape, and greater leaflet surfaces and tethering. MR severity was correlated with the MA area (r²?=?0.43, P?<?0.01) and the annulus circumference (r²?=?0.38, P?<?0.01). A logistic regression analysis indicated that the MA area (OR: 1.02, 95% CI: 1.01–1.03, P?<?0.01), AHCWR (OR: 0.24, 95% CI: 0.14–0.35, P?=?0.04) and MV tenting volume (OR: 3.24, 95% CI: 1.16–9.08, P?=?0.03) were independent predictors of MR severity in AF patients.

Conclusions

The mechanisms of “atrial functional MR” are complex and include dilation of the MA, flattening of the annular saddle shape and greater leaflet tethering.

     

剂量率等因素对聚乙烯辐照交联的影响

本文研究了聚乙烯塑料在＾６０Ｃｏ－γ射线辐照下,剂量率等因素对交联度的影响,实验结果表明：交联度随辐照强度提高而增加,当交联度相同时,不同的材料需不同的辐照剂量,在相同的辐照条件下,当制备样品的方法不同时,交联度也不同。     

沈阳西部污灌水中有机污染物的分析

沈阳西部污灌水中有机污染物的分析刘海玲,张丽珊,姚家彪,于殿臣,朱岩,可夫,姜萍（中国科学院沈阳应用生态研究所,１１００１５）ＡｎａｌｙｓｉｓｏｆＯｒｇａｎｉｃＰｏｌｌｕｔａｎｔｓｉｎＩｒｒｉｇａｔｅｄｓｅｗａｇｅＩｎＷｅｓｔｅｒｎＳｈｅｎｙａｎｇ．...     

对氨基苯甲酸酯同系物形成细胞色素P_（450）代谢中间体络合物的定量结构与活性关系

细胞色素Ｐ４５０（Ｐ４５０,Ｅｃ１．１４．１４．１）是一种十分重要的催化氧化反应的酶。本文测定了１２个对氨基苯甲酸酯同系物与Ｐ４５０相互作用而形成Ｐ４５０代谢中间体络合物的活性,用半经验分子轨道法ＭＮＤＯ－ＰＭ３计算得到了这些同系物的分子轨道指数,并用逐步多元回归分析法导出了活性与分子轨道指数及正辛醇／水分配系数的对数值（ＬｏｇＰ）之间的定量结构与活性关系（ＱＳＡＲ）。结果表明：对氨基苯甲酸脂同系物形成Ｐ４５０代谢中间体络合物的活性与原子净电荷的绝对值之和（∑Ｑ）和ＬｏｇＰ均具有很好的抛物线型相务性,同时,ＬｏｇＰ与∑Ｑ之间也存在相当好的相关性。