Protein architecture chronology deduced from structures of amino acid synthases

Inferring the protein architecture chronology is one of central topics in origin of life study and has been given much attention. Based on an amino acid evolutionary model that late amino acids were bio-synthesized prior to early counterparts, we addressed the issue by examining the structures of amino acid synthases. Despite the limited structural information on amino acid synthases, our deduction revealed that alpha/beta was the oldest protein class, which is in good agreement with the prior fold-usage-based conclusion.     

Population-genetic structure of Chuvashia (from data on eight DNA loci in the nuclear genome)

Population-genetic study of indigenous populations representing three ethnic Chuvash group: highland (Cheboksarsk and Morgaush district), lowland (Kanash district) and mid-lowland (Marposad district). Eight polymorphic DNA loci of the nuclear genome (VNTR/PAH, STR/PAH, VNTR/ApoB, VNTR/DAT1, APF, VNTR/eNOS, IVS6aGATT, and KM.19/PstI) were examined in the population of each district. For each of the four population, we estimated the allele and genotype frequency distributions at each polymorphic system, heterozygosities HS and between-population differences FST. In the combined Chuvash sample, HS = 0.464 and FST = 0.006. Loci VNTR(DAT) and VNTR(ApoB) showed highest between-population differentiation (0.009 < or = FST < or = 0.012), and loci IVS6aGATT, APF, VNTR/eNOS, and D7S23 (KM.19), lowest differentiation (0.001 < or = FST < or = 0.003). Analysis of genetic distances revealed somewhat higher genetic similarity between the Cheboksarsk and Morgaush populations belonging to the highland Chuvash group, whereas the highland Chuvash population from the Marposad district, which belong to the mid-lowland group, was more distant from the former populations.     

呼吸机呼气滤器的研制及防护效果评价

为防止呼吸机呼气管道中的含菌气体扩散污染病房空气,引发交叉感染。利用HEPA材料、活性炭、特殊的缓释杀菌滤材,研制成一套呼吸机呼气除菌过滤装置。经参照有关标准用物理模拟气溶胶颗粒(0.28-0.34um)及微生物气溶胶测试,过滤效率>99.995％,微生物气溶胶滤除率达100％。气流阻力<230Pa,完全能满足临床呼气机的过滤除菌使用条件。     

Cloning, expression, purification, and characterization of AmphiTip30, a member of short-chain dehydrogenases/reductases family from the amphioxus Branchiostoma belcheri tsingtauense

In this paper we describe the cloning, expression and identification study of the TIP30 gene from amphioxus (Branchiostoma belcheri). The amphioxus TIP30 cDNA is comprised of 1499 bp and is translated in one open-reading frame to give a protein of 237 amino acids, with a predicted 23 amino acids signal peptide, a 147 bp 5'-UTR and a 638 bp 3'-UTR. A multiple alignment of TIP30 from amphioxus with other known TIP30 sequences shows the conservation of most amino acid residues involved in the peculiar structural domains found within TIP30's. Phylogenetic analysis places AmphiTIP30 at the base of the phylogenetic tree, suggesting that AmphiTIP30 is the archetype of the vertebrate TIP30 genes. We express the amphioxus TIP30 gene in Escherichia coli. driven by T7 promoter. The recombinant amphioxus TIP30 protein was purified by HisTrap affinity column. Subsequently, the binding constant and enzyme activity was mensurated. Western blot and immunohistochemistry analysis confirmed that amphioxus has a native molecular mass of approximately 26 kDa, and TIP30 was strongly expressed in ovary. Finally, the initial function of TIP30 is discussed.     

High level soluble expression and one-step purification of IBDV VP2 protein in <Emphasis Type="Italic">Escherichia coli</Emphasis>

Objectives

To improve the expression of soluble IBDV VP2 protein by using different tagged vectors in Escherichia coli.

Results

Fusion tags, Grifin, MBP, SUMO, thioredoxin, γ-crystallin, ArsC and PpiB, enhanced the expression and solubility of VP2 protein. The fusion proteins were purified by Ni–NTA chromatography, MBP-VP2 showed the highest purity about 90 %. After removing the MBP tag, VP2 self-assembled into virus-like particles, ~25 nm diam. Results from AGP suggested the recombinant IBDV VP2 protein identified by reference serum like IBDV.

Conclusion

All the seven tags enhanced the expression and solubility of IBDV VP2 protein. The recombinant protein self-assembly into virus like particles and possess antigenicity as reference IBDV.

     

From Mesolithic hunters to Iron Age herders: a unique record of woodland use from eastern central Europe (Czech Republic)

Vegetation History and Archaeobotany - In a continuous, perfectly stratified sedimentary sequence which was discovered under a large sandstone overhang in northern Bohemia, Czech Republic, we...     

Expression of chemokine-like factor 1 is upregulated during T lymphocyte activation

Chemokine-like factor 1 (CKLF1) is a cytokine with chemotactic effects on leukocytes and a functional ligand of CCR4. This cytokine is widely expressed and the level of expression is reported to be upregulated in asthma and rheumatoid arthritis (RA), disease conditions in which T lymphocytes are over-activated. In order to determine the expression profile of CKLF1 in activated T lymphocytes, we first employed a PCR-based method on human blood fractions cDNA panels and found that CKLF1 was upregulated in activated CD4+ and CD8+ cells, with no obvious changes in CD19+ cells. We further performed kinetic analyses of CKLF1 expression in phytohemagglutinin (PHA)-stimulated human peripheral blood lymphocytes (PBL) at both the mRNA and protein levels. In resting PBL, the constitutive expression of CKLF1 was low at mRNA level and barely detectable at the protein level; however, both were remarkably upregulated by PHA, appearing at 8h after PHA-stimulation and persisting up to 72h. These results suggest that CKLF1 may be involved in T lymphocyte activation and further study of CKLF1 function will prove valuable.     

Pressure-induced metallization of condensed phase β-HMX under shock loadings via molecular dynamics simulations in conjunction with multi-scale shock technique

Thanks to the advances in grid technologies, we are able to propose here an evolution of our molecular simulator that, when moving to larger systems, instead of reducing the granularity of the dynamical treatment (as is often done in molecular dynamics studies of such systems) exploits the extra power of the grid approach to the end of preserving the detailed nature of theatomistic formulation of the interaction. Key steps of such evolution are: (1) the assemblage of the interaction based on a composition of the ab initio intramolecular data and a portable parameterization of the intermolecular potential linking ab initio evaluation of intramolecular potentials and the partitioning of molecular polarizability; (2) the exploitation of an efficient coordinated porting and running of molecular dynamics codes on the European grid distributed computing infrastructure. As a prototype case study, the N-methylacetamide dimer in vacuo has been considered and the formation of possible conformers is analyzed.