Testing relative evolutionary rates and estimating divergence times among six genera of Rhizophoraceae using cpDNA and nrDNA sequences

The molecular phylogenetic trees of 10 species representing 6 genera of the family Rhizophoraceae have been constructed using the sequences of chloroplast genesmatK andrbcL as well as the ITS regions of nuclear ribosomal DNA. Relative-rate tests between lineages in these phylogenetic trees have been performed. On the basis of the results of the relative-rate tests and related molecular evolutionary rate data, the divergence times between the lineages are estimated as follows: (i) the first divergence time in these genera is 132.25 million years ago (mya); (ii) the average divergence time between two tribes, i.e. inland Legnotideae (exceptCarallia brachiata) and mangrove Rhizophoreae, is 64.13 mya; and (iii) the average divergence time between two inland species,C. garciniaefolia andC. pectinifolia, is 19.92 mya.     

Cloning,sequencing and structural analysis of a pea cDNA encoding EF-1α

A cDNA library with the capacity of 2.0 × 10⁶ was constructed using mRNA extracted, from gibberellic acid (GA)-treated G2 pea seedlings and a 1.6 kb cDNA with 100 nucleotides of 5′ non-coding region and 223 nucleotides of 3′ non-coding region was obtained by random screening. The DNA fragment contains an open reading frame of 1 344 nucleotides and encodes 447 amino acids. Sequence analysis of DNA and deduced polypeptide demonstrated that it encoded for a pea elongation factor 1-alpha (EF-1α). The functional domains of EF-1α is well conserved and EF-1α can be a good candidate for studying molecular evolution.     

Phylogenetic relationships and divergence times of the family Araucariaceae based on the DNA sequences of eight genes

Araucariaceae is one of the most primitive families of the living conifers, and its phylogenetic relationships and divergence times are critically important issues. The DNA sequences of 8 genes, i.e., nuclear ribosomal 18S and 26S rRNA, chloroplast 16S rRNA, rbcL, matK and rps4, and mitochondrial coxl and atpl, obtained from this study and GenBank were used for constructing the molecular phylogenetic trees of Araucariaceae, indicating that the phyiogenetic relationships among the three genera of this family should be （（Wollemia, Agathis）, Araucaria）. On the basis of the fossil calibrations of Wollemia and the two tribes Araucaria and Eutacta of the genus Araucaria, the divergence time of Araucariaceae was estimated to be （308± 53） million years ago, that is, the origin of the family was in the Late Carboniferous rather than Triassic as a traditional view. With the same gene combination, the diver- gence times of the genera Araucaria and Agathis were （246 ± 47） and （61 ±15） Ma, respectively. Statis- tical analyses on the phylogenetic trees generated by using different genes and comparisons of the divergence times estimated by using those genes suggested that the chloroplast matK and rps4 genes are most suitable for investigating the phylogenetic relationships and divergence times of the family Araucariaceae.     

The complete mitochondrial DNA sequence and the phylogenetic position of Achalinus meiguensis (Reptilia: Squamata)

The mitochondrial genome complete sequence of Achalinus meiguensis was reported for the first time in the present study. The complete mitochondrial genome of A. meiguensis is 17239 bp in length and contains 13 protein-coding genes, 22 tRNA, 2 rRNA, and 2 non-coding regions (Control regions). On the basis of comparison with the other complete mitochondrial sequences reported, we explored the characteristic of structure and evolution. For example, duplication control regions independently occurred in the evolutionary history of reptiles; the pseudo-tRNA of snakes occurred in the Caenophidia; snake is shorter than other vertebrates in the length of tRNA because of the truncations of TψC arm (less than 5 bp) and “DHU“ arm. The phylogenic analysis by MP and BI analysis showed that the phylogenetic position of A. meiguensis was placed in Caenophidia as a sister group to other advanced snakes with the exclusion of Acrochordus granulatus which was rooted in the Caenophidia. Therefore we suggested that the subfamily Xenodermatinae, which contains A. meiguensis, should be raised to a family rank or higher rank. At the same time, based on the phylogenic statistic test, the tree of Bayesian was used for estimating the divergence time. The results showed that the divergence time between Henophidia and Caenophidia was 109.50 Mya; 106.18 Mya for divergence between Acrochordus granulatus and the other snakes of the Caenophidia; the divergence time of A. meiguensis was 103 Mya, and Viperidae diverged from the unilateral of Elapidae and Colubridae was 96.06 Mya.     

A new definition of restricted Lie superalgebras

A new definition of restricted Lie superalgebras has been given; some important results on the representation theory of restricted Lie superalgebra have been obtained.     

Asian origin for Polystichum （Dryopteridaceae） based on rbcL sequences

Chloroplast rbcL sequences of 60 species of Polystichum sensu lato (s.l.), including 23 new sequences from southwest China, were used to assess the phylogenetic relationships within the genus. On the basis of estimated evolution rate of rbcL gene and the genetic distance data that passed relative-rate tests, we further estimated the divergence times between some clades of the genus. The phylogenetic relationships were inferred using the neighbor-joining and maximum-parsimony methods, both methods producing trees with completely congruent topology. These trees reveal that all species of Polystichum s.l. in this study (including Cyrtomium and Cyrtomidictyum) form a monophyletic group. The basal split in Polystichum s.l. separates a clade with all Asian members from a clade containing other species from all over the world. The phylogenetic and divergence time estimation results lead us to suggest that Polystichum s.l. originated in Asia in the late Late Cretacous (≈76 Ma) and migrated into other places in the world in early Eocene(≈46 Ma).     

Synthesis of nanoporous silica with interior composite cells with synthetic block copolypeptide as template

IN NATURE,PROTEIN AND POLYSACCHARIDE ARE INVOLVED IN THE FORMATION OF A REMARKABLE DIVERSITY OF EXQUISITE NANOSTRUCTURED SILICATES IN BIOLOGICAL SYSTEMS SUCH AS DIATOMS AND SPONGES.THE SILAFFIN[1]AND SILICATEIN[2]ISOLATED FROM MARINE DIATOMS AND SPONGES C…     

Overexpression of phospholipase <Emphasis Type="Italic">D</Emphasis>α gene enhances drought and salt tolerance of <Emphasis Type="Italic">Populus tomentosa</Emphasis>

The cDNA of AtPLDa （Arabidopsis thaliana Phospholipase Da） gene was introduced into P. tomentosa （Populus tomentosa） under the control of the Cauliflower mosaic virus 35S promoter. Southern and Northern blot analyses suggested that the AtPLDa gene has been transferred into the P. tomentosa genome. No obvious morphological or developmental difference was observed between the transgenic and wild-type （WT） plants. Drought and salt tolerance and gene expression of seedlings of several transgenic lines and WT plants （control） were studied. The results showed that the rhizogenesis rate and the average root-length of transgenic lines were significantly higher than WT plants after mannitol and NaCI treatment under the same growth conditions. Northern blot analysis indicated that the higher the PLDa expression in the transgenic plants, the more tolerant the transgenic plants are to drought and salt treatment. Meanwhile, another group of these transgenic lines and WT plants （control） were treated with PEG6000 and NaCI separately. The contents of chlorophylls and the activities of some anti- oxidant enzymes （superoxide dismutase, guaiacol peroxidase and catalase） as well as malondialdehyde and relative electrical conductivity were analyzed. Altogether, our results demonstrated that overexpression of the PLDa gene can enhance the drought and salt tolerance in transgenic P. tomentosa plants.     

α-LTX and α-LTXN4C induce [Ca2+]i elevation through different mechanisms in pancreatic β cells

α-latrotoxin (α-LTX) is the only neurotoxin from black-widow spider which has secretagogue effects in the vertebrates. It causes massive neurotransmitter and hormone release via two instinct mechanisms after binding with its high-affinity membrane recep…     

Synthesis and micellization behavior of stimuli-responsive polypeptide hybrid triblock copolymer

Polypeptide hybrid triblock copolymer, poly（L-glutamic acid）-b-poly（propylene oxide）-b-poly （L-glutamic acid） （PLGA-b-PPO-b-PLGA）, was synthesized by the ring-opening polymerization of benzyI-L- glutamic N-carboxyanhydride （BLG-NCA） using poly（propylene glycol） bis（2-aminopropyl ether） as initiator, followed by the subsequent deprotection step. The obtained double hydrophilic triblock co- polymer exhibits ＂schizophrenic＂ micellization behavior in aqueous solution upon dually playing with solution pH and temperature. The multi-responsive micellization behavior of this polypeptide hybrid triblock copolymer has been thoroughly investigated by 1H NMR, laser light scattering （LLS）, tempera- ture-dependent optical transmittance, and circular dichroism spectroscopy （CD）.     

Preparation of MCM-41-supported chiral Salen Mn （Ⅲ） catalysts and their catalytic properties in the asymmetric epoxidation of olefins

A secondary amino-modified mesoporous molecular sieve MCM-41 was obtained by reaction of bis(3-(triethoxysilyl)propyl)amine with MCM-41. The chiral Salen-Mn (III) complex was anchored onto the modified MCM-41 by a multi-step grafting method and two heterogenized catalysts with different Mn contents were obtained. The catalysts were characterized by XRD, N2 adsorption, ICP, FT-IR and DR UV-Vis. Their catalysis on asymmetric epoxidation of several olefins was studied with NaClO and m-CPBA as oxidants respectively. It was found that both the activity and enantioselectivity of the cata- lysts decreased after the homogeneous catalyst was heterogenized. The reasons resulting in the de- crease of catalytic performance were discussed.     

Synthesis of novel organophosphorus C60 dimers

DUE TO THEIR OUTSTANDING PHYSICAL AND CHEMICALPROPERTIES,FULLERENE DIMERS HAVE PROVEN TO BE ATTRACTIVENANO-SCALE ORGANIC COMPOUNDS IN VARIOUS FIELDS SUCH ASNONLINEAR OPTICS,ORGANIC MATERIALS,BIOLOGY AND MEDI-CINE[1].AMONG THE FULLERENE DIMERS THAT HAVE BE…     

Investigation on chain structure of LLDPE obtained by ethylene in-situ copolymerization with DSC and XRD

Thermal segregations of LLDPE were treated with successive self-nucleation/annealing (SSA) on dif-ferential scanning calorimetry (DSC). Information on molecular heterogeneity of LLDPE was obtained. After SSA was treated, the multiple endothermic peaks were observed in the DSC thermograms during heating experiment. It is obtained that the thickness of different lamellas formed by segments of vari-ous lengths was 4―10 nm. X-ray diffraction (XRD) results showed that the crystallites dimensions of various reflections were about several dozens of nanometers. The ethylene/α-olefin copolymers and the copolymer via in-situ copolymerization were similar to each other for molecular heterogeneity and XRD characteristics, which revealed that it was possible to use the ethylene/α-olefin copolymers to simulate the copolymer via in-situ copolymerization of ethylene to simplify the complexity of the structure of the ethylene in-situ copolymer.     

Surface Dissociation Properties of Short Chain Carboxyl Mercaptan Self-Assembled Monolayers by Impedance Titration

Impedance titration was used to determine the surface dissociation characteristics of short-chain carboxyl mercaptan self-assembled monolayers （SAMs）. Based on the change of the cyclic voltammetric peak current and the charge-transfer resistance, which was related to pH value of the solution, the surface pKa of mercaptoacetic acid（MA）, 3-mercaptopropionic acid（MPA） and ω-mercaptohexanic acid（MHA） self-assembled membranes, with ionic strength being 0.1 mol/L, were determined to be 5.20, 4.80, 7.40, respectively. In addition, factors such as time needed for assembling, structure of monolayers and ionic strength, which effected the surface pKa, were studied as well. Such surface pKa shifts were sufficiently explained by interactions between interfacial molecules and hydrophobicity.     

杂交松组织培养中外植体的灭菌方法

在实验室内对来自广西大学林学院苗圃、东门林场苗圃、广西林业局种苗基地的杂交松 (Pinus elliottii× P.caribaea)外植体进行 75 %酒精 10 s+0 .1%升汞 4～ 6 min灭菌试验。其中 ,东门林场苗圃的外植体进一步采用 75 %酒精 10 s+0 .1% Hg Cl2 6 m in结合添加入培养基中的 1.2 %大蒜液的灭菌方法进行试验。结果表明 :广西大学林学苗圃的杂交松外植体 ,采用 75 %酒精 10 s+0 .1%升汞 5～ 6 m in的灭菌方法效果较好。东门林场苗圃以及广西林业局种苗基地的杂交松外植体用 75 %酒精 +0 .1%升汞的灭菌方法效果不理想。东门林场苗圃的枝条用 75 %酒精 10 s+0 .1% Hg Cl2 6 min结合添加入培养基中的 1.2 %大蒜液的灭菌方法效果较好。     

Interaction between integrin αIIbβ3 and synthesized cyclic hexapeptide containing RGD

The RGD sequence generally exists in the extracellular matrix proteins and can be recognized by many integrin proteins. The binding ability of immobilized biotinylated cyclic hexapeptide [cyclo(-Arg-Gly-Asp-D-Phe-Lys-Gly-)] containing RGD to integrin α_αbβ₃ was tested by the methods of ELISA and SPR. Results showed that a spacer of 1.48–2.2 nm between the peptide and the biotin residue was long enough to send the RGD sequence into the binding center embccedded within α_IIbβ₃, and the equilibrium dissociation constant was 1.1 μm. The work provides an ideal model system for the research of cell adhesion on solid surfaces.