Structure–function relationship and evolutionary history of the human selenoprotein M (SelM) found over-expressed in hepatocellular carcinoma

In humans we know 25 selenoproteins that play important roles in redox regulation, detoxification, immune-system protection and viral suppression. In particular, selenoprotein M (SelM) may function as thiol disulfide oxidoreductase that participates in the formation of disulfide bonds, and can be implicated in calcium responses. However, it presents a redox motif (CXXU), where U is a selenocysteine, and may also function as redox regulator because its decreased or increased expression regulated by dietary selenium alters redox homeostasis. No data are reported in literature about its involvement in cancer but only in neurodegenerative diseases. In this paper we evaluated the SelM expression in two hepatoma cell lines, HepG2 and Huh7, compared to normal hepatocytes. The results suggested its involvement in hepatocellular carcinoma (HCC) as well as its possible use to follow the progression of this cancer as putative marker. The aim of this study has been to analyze the structure–function relationships of SelM. Hence, firstly we studied the evolutionary history of this protein by phylogenetic analysis and GC content of genes from various species. So, we modeled the three-dimensional structure of the human SelM evaluating its energetic stability by molecular dynamics simulations. Moreover, we modeled some of its mutants to obtain structural information helpful for structure-based drug design.     

淫羊藿属十二个种的核型

用细胞压片法对12个淫羊藿属(Epimedium)植物的根尖有丝分裂进行了观察,并对其核型进行了比较研究。结果表明:这12种淫羊藿在核型上基本相似,都有1对中间随体染色体,而且都为对称核型。粗毛淫羊藿(E.acuminatum)、印江淫羊藿(E.yinjiangense)、单叶淫羊藿(E.simplicifloum)、巫山淫羊藿(E.wushanense)、光叶淫羊藿(E.myrianthum)、宝兴淫羊藿(E.davidi)、罗甸淫羊藿(E.luodianense)、木鱼坪淫羊藿(E.franchetii)、箭叶淫羊藿(E.sagittatum)、E.pubigerum、高山淫羊藿(E.alpinum)等11个种的核型公式均为2n=2x=6m(2SAT) 6sm,而黔岭淫羊藿(E.leptorrhizum)的核型公式为2n=2x=8m(2SAT) 4sm。结果显示12种淫羊藿的体细胞染色体数目均为2n=12,基数X=6;都属于对称核型、都有1对中间随体;染色体均为m、sm两种类型。     

The Hypothesis of a Genetic Protolanguage: an Epistemological Investigation

Progress in molecular biology has revealed profound relations between linguistic and genomic sciences, mainly through advances in bioinformatics. The structural symmetries between biochemical and verbal syntaxes raise the question of their origins: did they emerge independently, or did one arise from the other? Does the genetic code contain the traces of a protolanguage, a universal grammar whose gradual evolution and successive mutations progressively led to the polymorphism of natural languages? To explore this question, we review the isomorphism of the genetic code and verbal codes from lexical, syntactic, semantic and pragmatic standpoints. We discuss the limits of these symmetries and their anthropomorphic connotations. We observe the gradual evolution of species and languages according to parallel mechanisms, and the genetic roots of the physiology of language. In conclusion, we hypothesize that human observers may not be projecting linguistic frameworks onto genomic structures. Rather, it could be their linguistic faculties that reflect the grammatical structure of genetic code.     

Mathematical Modelling of a Class of Paleontological Evolution Processes

The time-dependent behaviour of number of genera in taxa replacing one another phylogenetically is studied with the help of a simple differential equation model with time-dependent or state-dependent coefficients.     

捕食线虫真菌rDNA ITS区间RFLPs分析

利用PCR-RFLP方法对捕食线虫真菌进行了系统发育研究。以ITS1和ITS4为引物对3属14种16个菌株的核糖体DNA转录间区（ITS）进行了PCR扩增,4种内切酶（AluI、HaeIII、HpaII、TaqI）酶切,结果表明不同属的ITS区长度没有明显差异,其长度范围在585～695之间。酶切图谱种间差别明显,种内基本一致,同属菌株图谱没有特异性,暗示传统的分属可能过细,某些属的成立还有待商榷,PCR-RFLP对确定疑难种的地位有重要意义,但不适用于种下水平的系统学研究。     

羧酸还原酶的研究进展

羧酸还原酶(carboxylic acid reductases,CARs)可以催化羧酸还原为相应的醛,反应条件温和、拥有广阔的底物范围且副反应较少。本文旨在综述近年来羧酸还原酶系统发育、结构与催化机理、蛋白质工程和固定化工程等方面的研究成果,揭示其作为重要工具酶在生物转化及合成生物学中的应用前景。     

Characterization of the Influence of Unsaturated Free Fatty Acids on Brain GABA/Benzodiazepine Receptor Binding In Vitro

Abstract: We have investigated the effect of unsaturated free fatty acids (FFAs) on the brain GABA/benzodiazepine receptor chloride channel complex from mammalian, avian, amphibian, and fish species in vitro. Unsaturated FFAs with a carbon chain length between 16 and 22 carbon atoms enhanced [³H]diazepam binding in rat brain membrane preparations, whereas the saturated analogues had no effect. The enhancement of [³H]diazepam binding by oleic acid was independent of the incubation temperature (0-30°C) of the binding assay and not additive to the enhancement by high concentrations of C1. In rat brain preparations, the stimulation of [³H]diazepam binding by oleic acid (10^?4M) was independent of the ontogenetic development. Phylogenetically, large differences were found in the effect of unsaturated FFAs on [³H]diazepam and [³H]muscimol binding: In mammals and amphibians, unsaturated FFAs enhanced both [³H]-muscimol and [³H]diazepam binding to 150-250% of control binding. In 17 fish species studied, oleic acid (10^?4M) stimulation of [³H]diazepam binding was weak (11 species), absent (four species), or reversed to inhibition (two species), whereas stimulation of [³H]muscimol binding was of the same magnitude as in mammals and amphibians. In 10 bird species studied, only weak enhancement of [³H]muscimol binding (110–130% of control) by oleic acid (10^?4M) was found, whereas [³H]diazepam binding enhancement was similar to values in mammal species. Radiation inactivation of the receptor complex in situ from frozen rat cortex showed that the functional target size for oleic acid to stimulate [³H]flunitrazepam binding has a molecular mass of ～200,000 daltons. Our data show that unsaturated FFAs have distinct effects on membranebound GABA/benzodiazepine receptors in vitro.