Mammalian Target of Rapamycin (mTor) Mediates Tau Protein Dyshomeostasis: IMPLICATION FOR ALZHEIMER DISEASE*

Previous evidence from post-mortem Alzheimer disease (AD) brains and drug (especially rapamycin)-oriented in vitro and in vivo models implicated an aberrant accumulation of the mammalian target of rapamycin (mTor) in tangle-bearing neurons in AD brains and its role in the formation of abnormally hyperphosphorylated tau. Compelling evidence indicated that the sequential molecular events such as the synthesis and phosphorylation of tau can be regulated through p70 S6 kinase, the well characterized immediate downstream target of mTor. In the present study, we further identified that the active form of mTor per se accumulates in tangle-bearing neurons, particularly those at early stages in AD brains. By using mass spectrometry and Western blotting, we identified three phosphoepitopes of tau directly phosphorylated by mTor. We have developed a variety of stable cell lines with genetic modification of mTor activity using SH-SY5Y neuroblastoma cells as background. In these cellular systems, we not only confirmed the tau phosphorylation sites found in vitro but also found that mTor mediates the synthesis and aggregation of tau, resulting in compromised microtubule stability. Changes of mTor activity cause fluctuation of the level of a battery of tau kinases such as protein kinase A, v-Akt murine thymoma viral oncogene homolog-1, glycogen synthase kinase 3β, cyclin-dependent kinase 5, and tau protein phosphatase 2A. These results implicate mTor in promoting an imbalance of tau homeostasis, a condition required for neurons to maintain physiological function.     

Survival of Escherichia coli O157:H7 in Soils from Vegetable Fields with Different Cultivation Patterns

Escherichia coli O157:H7 survived longer in soils from plastic-greenhouse cultivation than soils from the open field. Soil pH, organic carbon levels, and the ratio of bacterial phospholipid fatty acids (PLFAs) to fungal PLFAs played the significant roles in survival of O157:H7. Greater attention should be paid to the control of pathogen contamination under conditions of plastic-greenhouse cultivation.     

Microbiological Identification and Analysis of Swine Lungs Collected from Carcasses in Swine Farms, China

The primary objective of this 3 years study was to determine the prevalence of porcine pathogens of the lungs of swine in swine farms in southern China. A total of 5,420 samples were collected from 200 swine farms. The bacterium that was most commonly isolated was Streptococcus suis, with 10.24 % of the samples being positive, 114 lungs (2.1 %) were positive for pseudorabies virus and 263 (4.85 %) were positive for classical swine fever virus; much lower than positive for PRRSV (15.1 %, p = 0.023) and PCV2 (13.8 %, p = 0.038). lungs that were positive for PRRSV and/or PCV-2 have significantly increased odds of being positive for any of the S. suis (9.79 vs. 0.44 %, p = 0.003).     

PEGylated human catalase elicits potent therapeutic effects on H1N1 influenza-induced pneumonia in mice

Therapeutic recombinant human catalase (rhCAT) can quench infection-induced reactive oxygen species (ROS), thereby alleviating the associated tissue damage. Although the intranasal route is efficient to deliver native rhCAT to the lung, the therapeutic effect is limited by rapid elimination from the blood. In this study, we modified rhCAT with the active polymer, polyethylene glycol monomethyl ether (PEG)-5000, and analyzed the pharmacokinetics of PEGylated rhCAT in mice. The high tetra-PEGylation ratio was about 60 %, and PEGylation prolonged the half-life of rhCAT in serum (75 vs. 13.5 min for native rhCAT). The protective effects of PEG-rhCAT were investigated in a mouse model of influenza virus A (H1N1)-associated pneumonia. PEG-rhCAT was more effectively delivered than native rhCAT and was associated with higher survival ratio, less extensive lung injuries, reduced ROS levels, and lower viral replication. Collectively, these findings indicate that PEGylation can enhance the therapeutic efficacy of native rhCAT and suggest that PEGylated rhCAT may represent a novel complement therapy for H1N1 influenza-induced pneumonia.     

Vibrio zhuhaiensis sp. nov., isolated from a Japanese prawn (Marsupenaeus japonicus)

A Gram-negative, oxidase-positive, facultatively anaerobic bacterium, designated strain E20121, was isolated from the digestive tract of a Japanese prawn (Marsupenaeus japonicus) collected from the coastal sea water area of Zhuhai, Guangdong province, China. The new isolate was determined to be closely related to Vibrio ponticus DSM 16217^T, having 97.6 % 16S rRNA gene sequence similarity. Phylogenetic analysis based on recA, pyrH and rpoA also showed low levels of sequence similarities (72.6–96.6 %) with all species of the genus Vibrio. A multigene phylogenetic tree using concatenated sequences of the four genes (16S rRNA, rpoA, recA and pyrH) clearly showed that the new isolate is different from the currently known Vibrio species. DNA–DNA hybridization experiments revealed similarity values below 70 % with the closest related species V. ponticus DSM 16217^T. Several phenotypic traits enabled the differentiation of strain E20121 from the closest phylogenetic neighbours. The DNA G+C content of strain E20121 was determined to be 47.6 mol % and the major fatty acid components identified were C_16:1ω7c and/or C_16:1ω6c (39.8 %), C_18:1ω7c (13.6 %) and C_16:0 (9.6 %). Based on genotypic, phenotypic, chemotaxonomic, phylogenetic and DNA–DNA hybridization analyses, strain E20121 is proposed to represent a novel species of the genus Vibrio for which the name Vibrio zhuhaiensis sp. nov. is proposed. The type strain is E20121^T(=DSM 25602^T = CCTCC AB 2011174^T).     

Structure-based design and synthesis of potent benzothiazole inhibitors of interleukin-2 inducible T cell kinase (ITK)

Inhibition of the non-receptor tyrosine kinase ITK, a component of the T-cell receptor signalling cascade, may represent a novel treatment for allergic asthma. Here we report the structure-based optimization of a series of benzothiazole amides that demonstrate sub-nanomolar inhibitory potency against ITK with good cellular activity and kinase selectivity. We also elucidate the binding mode of these inhibitors by solving the X-ray crystal structures of several inhibitor-ITK complexes.     

Phylogeography of Sophora davidii (Leguminosae) across the ‘Tanaka‐Kaiyong Line’, an important phytogeographic boundary in Southwest China

The ‘Tanaka‐Kaiyong Line’ (TKL) is a major phytogeographic boundary in Southwest China, separating East Asia's Sino‐Himalayan and Sino‐Japanese Floras. However, little is known about the importance of this boundary in promoting intraspecific phylogeographic subdivision and divergence. Using chloroplast (cpDNA) and nuclear‐intron (nDNA) sequence data, we reconstructed the population history of Sophora davidii, a drought‐tolerant riparian shrub widely distributed on either side of the TKL. Specifically, we aimed at testing two long‐standing explanations for possible vicariant events across the TKL: (i) Late Pliocene (c. 3 Ma) geological uplift of the eastern Qinghai‐Tibetan Plateau (QTP) or (ii) a sharp environmental gradient associated with the establishment of different monsoon regimes on either side of the TKL during the (Late) Pleistocene. Our genealogical analyses detected a major west–east split in cpDNA, geographically largely consistent with the TKL, and dated to c. 1.28 Ma (95% HPD: 0.21–2.96 Ma), hence postdating the latest phase of eastern QTP uplift. Furthermore, integrating cpDNA phylogeographic patterns with mismatch analyses, we found multiple refugial isolation and long‐term demographic stability of populations in the west (Hengduan Mountain Range) compared with extensive range expansions in the east, possibly during the last glacial period(s) and followed by differentiation into regional sublineages (southeast: Yunnan‐Guizhou Plateau vs. northeast: Qinling Mts./Loess Plateau). Although nuclear differentiation was less marked, the geographical pattern of nDNA haplotypes provided some further indication of the species' eastward expansion, possibly from source populations located just east of the TKL (lower Jinshajiang region). Overall, the present data reject the geological (tectonic) explanation for the TKL and, instead, provide supportive evidence for its role as a climatically driven barrier to present‐day plant dispersal. In addition, our study highlights changing temperatures and vegetation types during the last glacial period(s), along with aspects of regional topography, to be important determinants of the glacial eastward expansion of S. davidii. In consequence, our study lends support to a ‘glacial out‐of‐Hengduan Mts’. hypothesis for the xerophytic‐riparian flora of Southwest China, which in turn is inconsistent with the traditional view of the TKL as a ‘classical’ vicariant‐biogeographic boundary.     

Open-Channel Structures of the Human Glycine Receptor α1 Full-Length Transmembrane Domain

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Hexokinase from grape berries: its prokaryotic expression, polyclonal antibody preparation and biochemical property analyses

Two full-length hexokinase (HXK, EC 2.7.1.1) cDNAs, VvHXK1 with 1,413 bp and VvHXK2 with 1,458 bp were cloned from grape berries (Vitis vinifera L. Cabernet Sauvignon). VvHXK1 and VvHXK2 genes sequence from grape berries were deposited in GenBank under the accession number JN118544 and JN118545, respectively. The homology of the amino acid of VvHXK1 or VvHXK2 was very similar to ‘Pinot Noir’ grape HXK sequence, their similarties were 99.36 % and 98.97 %, respectively. More intuitive phylogenetic tree showed that the homology of amino acid sequence VvHXK1 with melon CmHXK1 was 86 %, and VvHXK2 homology with rice OsHXK3 was 83 %. The HXK proteins were successfully expressed in plasmid pET-30a (+) vectors in Escherichia coli BL21 (DE3) pLysS. The expressed proteins were purified using Ni-NTA agarose column and used to produce HXK1 antibody and conducted HXK protein blotting analysis. The results,suggested that one polypeptide band of about 51 kDa HXK protein can be detected in grape berries, HXK protein level was the highest during early grape berry development, but the lowest from 50d to 60d during development. Biochemical analysis of two hexokinase isozymes indicated that glucose was the optimal substrate of HXK, The isoelectric points of the two isozymes were 5.8 and 5.6, respectively. And the optimum pH was about 8.0. These results provide a substantial basis for the further studies of functions of grape HXKs to manipulate sugar content of grape berries.