Observations complémentaires sur l'ichthyofaune des marnes messiniennes des environs d'Alba (Piémont,Italie)

The study of the fossil fishes gathered in themessinian marls outcropping in the neighbourhood of Alba (Piedmont, Italy), between Santa-Vittoria d'Alba and Costigliole d'Asti, leads one to complete the faunal list of these localities in which eight species are presently known. Five of them are euryhaline and characterize a variable salt-content environment. The three other species are, on the contrary, stenohaline. Their occurrence gives undoubtedly evidence of the immediate proximity of the sea during the deposition of the marls overlying the primary gypsum bed.     

Structure of Thermoplasma volcanium Ard1 belongs to N-acetyltransferase family member suggesting multiple ligand binding modes with acetyl coenzyme A and coenzyme A

Acetylation and deacetylation reactions result in biologically important modifications that are involved in normal cell function and cancer development. These reactions, carried out by protein acetyltransferase enzymes, act by transferring an acetyl group from acetyl-coenzymeA (Ac-CoA) to various substrate proteins. Such protein acetylation remains poorly understood in Archaea, and has been only partially described. Information processing in Archaea has been reported to be similar to that in eukaryotes and distinct from the equivalent bacterial processes. The human N-acetyltransferase Ard1 (hArd1) is one of the acetyltransferases that has been found to be overexpressed in various cancer cells and tissues, and knockout of the hArd1 gene significantly reduces growth rate of the cancer cell lines. In the present study, we determined the crystal structure of Thermoplasma volcanium Ard1 (Tv Ard1), which shows both ligand-free and multiple ligand-bound forms, i.e.,Ac-CoA- and coenzyme A (CoA)-bound forms. The difference between ligand-free and ligand-bound chains in the crystal structure was used to search for the interacting residues. The re-orientation and position of the loop between β4 and α3 including the phosphate-binding loop (P-loop) were observed, which are important for the ligand interaction. In addition, a biochemical assay to determine the N-acetyltransferase activity of Tv Ard1 was performed using the T.volcanium substrate protein Alba (Tv Alba). Taken together, the findings of this study elucidate ligand-free form of Tv Ard1 for the first time and suggest multiple modes of binding with Ac-CoA and CoA.     

牡丹试管苗玻璃化的研究

以MS为基本培养基,研究品种、琼脂、6-BA、大量元素、蔗糖、光照等因素对牡丹试管苗玻璃化的影响。结果显示：不同品种的牡丹试管苗在组织培养的过程中,出现不同程度的玻璃化,增加培养基中琼脂浓度、降低细胞分裂素6-BA的浓度、降低大量元素的浓度和增加光照强度或采用自然光照均可以有效地降低试管苗玻璃化。     

Gen‐morph species concept—A new and integrative species concept for outbreeding organisms

The present article briefly reviewed the prevailing species concepts, especially biological, genetic, evolutionary, phylogenetic, ecological, and several taxonomic species concepts. The former five reflect the properties of species from diverse aspects and in different degrees, while taxonomic species concepts all contain more or less subjective elements, except for Hedberg's taxonomic method (not species concept). So far, there is no species concept that is both theoretically rational and practically operable. The present article outlined recent studies on the genus Paeonia L. (Paeoniaceae) in biology, particularly in morphology, biogeography, molecular phylogeny, and reproductive behavior, which provided insight into the relationship between variation of morphological characteristics and phylogeny. Taking the study on Paeonia L. as a case, referring to studies on some other plant groups, and incorporating the merits of the prevailing species concepts into our consideration, “gen‐morph species concept” is proposed here formally as new for outbreeding organisms. The new species concept has three special features: (i) a bridge linking morphological aspect with genetic and other aspects of species; (ii) proposal of a concrete morphological criterion for species definition, and (iii) considering quantitative and qualitative characteristics as equally valuable for species definition and introducing statistics into the concept to handle such characteristics. Therefore, the gen‐morph species concept is an integrative species concept, both theoretically objective and practically operable.     

Crystal structure of human RPP20-RPP25 proteins in complex with the P3 domain of lncRNA RMRP

Human RNase MRP ribonucleoprotein complex is an essential endoribonuclease involved in the processing of ribosomal RNAs, mitochondrial RNAs and certain messenger RNAs. Its RNA subunit RMRP catalyzes the cleavage of substrate RNAs, and the protein components of RNase MRP are required for activity. RMRP mutations are associated with several types of inherited developmental disorders, but the pathogenic mechanism is largely unknown. Recent structural studies shed lights on the catalytic mechanism of yeast RNase MRP and the closely related RNase P; however, the structural and catalytic mechanism of RMRP in human RNase MRP complex remains unclear. Here we report the crystal structure of the P3 domain of RMRP in complex with the RPP20 and RPP25 proteins of human RNase MRP, which shows that the P3 RNA binds to a conserved positively-charged surface of the RPP20-RPP25 heterodimer through its distal stem and internal loop regions. The disease-related mutations of RMRP^P3 are mostly located at the protein-RNA interface and are likely to weaken the binding of P3 to RPP20-RPP25. Moreover, the structure reveals a homodimeric organization of the entire RPP20-RPP25-RMRP^P3 complex, which might mediate the dimerization of human RNase MRP complex in cells. These findings provide structural clues to the assembly and pathogenesis of human RNase MRP complex and also reveal a tetrameric feature of RPP20-RPP25 evolutionarily conserved with that of the archaeal Alba proteins.     

Antioxidative Activity of Resveratrol and Its Derivatives Isolated from Seeds of Paeonia lactiflora

Seven stilbenes, a new cis-ε-viniferin and the six known stilbenes, trans-resveratrol, trans-resveratrol-4′-O-β-D-glucopyranoside, trans-ε-viniferin, gnetin H, and suffruticosol A and B, were isolated and identified from seeds of Paeonia lactiflora. The antioxidative activity of these stilbene derivatives was evaluated against the 2-deoxyribose degradation and rat liver microsomal lipid peroxidation induced by the hydroxyl radical generated via a Fenton-type reaction. Among these stilbenes, trans-ε-viniferin and gnetin H significantly inhibited 2-deoxyribose degradation and lipid peroxidation in rat liver microsomes. In addition, cis-ε-viniferin, and suffruticosol A and B also exhibited moderate antioxidative activity. These results suggest that resveratrol dimers and trimers, together with resveratrol from seeds of Paeonia lactiflora may be useful as potential sources of natural antioxidants.     

Paeonia rotundiloba (D.Y.Hong) D.Y.Hong: A new status in tree peonies (Paeoniaceae)

Paeonia decomposita Hand.-Mazz.subsp,rotundiloba D.Y.Hong is here raised to the specific rank,P.rotundiloba (D.Y.Hong) D.Y.Hong,based on its distinctiveness of four diagnostic characters:number of carpels;height of disk; number of leaflets of the lower leaves,and shape of the terminal leaflets; and unpublished molecular data.Paeonia rotundiloba differs distinctly from P.decomposita in having carpels mostly 3,less often 2 or 4,very rarely 5 (vs.almost always 5,very occasionally 4 or 3),disk 8-15 mm high (vs.4-9.6 mm),leaflets mostly 19-39(vs.29-63) in number,and ratio of length to width of the terminal leaflets 1.09-1.93 (vs.1.81-2.99).     

大花黄牡丹内生菌的分离鉴定及其抗菌活性菌株的筛选

采用研磨法从健康大花黄牡丹的根、茎、叶柄、叶和种子中进行菌种分离,依据其形态、培养特征及其他生物学特性对菌株进行初步鉴定;采用平板对峙法对分离的内生菌进行拮抗试验研究,并对强活性菌株进行16S rD-NA序列鉴定,以明确大花黄牡丹内生菌的种类,筛选对农作物病害有抑制作用的菌株.结果表明:(1)获得内生真菌188株,鉴定为10个属,以短蠕孢属(50％)、青霉孢属(18.6％)和曲霉孢属(12.3％)为优势种群.获得内生放线菌145株,以链霉菌属(98.6％)为优势种群.表明大花黄牡丹内生菌在数量和种类上存在极丰富的多样性,同时在不同组织存在一定的差异性.(2)抑菌试验结果显示,21.6％真菌对指示菌有抑菌作用,抑菌圈直径最大为10mm;27.8％放线菌对指示菌有抑菌作用,其中菌株PND31的抑菌活性较强,抑菌谱较广.(3)16S rDNA序列鉴定显示,菌株PND31与链霉菌属聚在一起,初步归为链霉菌属一个种.     

滇牡丹花色类群性状变异分析

对滇牡丹（Paeonia delavayi）10个花色类群的13个数量性状和5个质量性状进行了调查及统计分析,结果表明：（1）未发现所有花部性状均为同色的花色类群;（2）从花色与其它质量性状的连锁看,绿色类群均具绿色柱头,且是唯一存在直立花朵、绿色花丝、绿色花药的类群;（3）10个花色类群13个数量性状的平均变异系数范围为32．80％～50．56％,说明不同类群内个体问的性状稳定性差异较大;（4）10个花色类群平均表型分化系数为42．25％,表明滇牡丹10个花色类群表型变异主要来源于类群内,类群间的表型变异也很突出;（5）据花色演化趋势,初步推断云南省迪庆州中甸、德钦一带可能为滇牡丹的起源中心。