Acceleration of alpha-synuclein aggregation by homologous peptides.

alpha-Synuclein (alpha-Syn), amyloid beta-protein and prion protein are among the amyloidogenic proteins that are associated with the neurodegenerative diseases. These three proteins share a homologous region with a consensus sequence mainly consisting of glycine, alanine and valine residues (accordingly named as the GAV motif), which was proposed to be the critical core for the fibrillization and cytotoxicity. To understand the role of the GAV motif in protein amyloidogenesis, we studied the effects of the homologous peptides corresponding to the sequence of GAV motif region (residues 66-74) on alpha-Syn aggregation. The result shows that these peptides can promote fibrillization of wild-type alpha-Syn and induce that of the charge-incorporated mutants but not the GAV-deficient alpha-Syn mutant. The acceleration of alpha-Syn aggregation by the homologous peptides is under a sequence-specific manner. The interplay between the GAV peptide and the core regions in alpha-Syn may accelerate the aggregation process and stabilize the fibrils. This finding provides clues for developing peptide mimics that could promote transforming the toxic oligomers or protofibrils into the inert mature fibrils.

[An improved solid phase synthesis of human proinsulin C-peptide].

Human proinsulin C-peptide with C-terminal glutamine amide could be prepared through solid phase method by combining the gamma-carboxyl group of glutamic acid with the amino group of MBHA resin. The protecting groups were cleaved by HF. MBHA resin is relatively inexpensive. The new method is another way for the preparation of human proinsulin C-peptide. The preparation human proinsulin C-peptide of analogue using of PAM resin was also reported.

B22 Glu des-B30 insulin: a novel monomeric insulin.

Studies on monomeric insulin with reduced self-association are important in the development of insulin pharmaceutical preparations with rapid hypoglycemic action on patients with diabetes. Here we report a novel monomeric insulin, B22 Glu des-B30 insulin, prepared from a single chain insulin precursor with B22 Arg mutated to Glu, which was expressed in Pichia pastoris and converted to B22 Glu des-B30 insulin by tryptic digestion. It still retains 50% of the in vivo biological activity of porcine insulin and does not form a dimer even at a concentration of 10 mg/ml, showing that B22 Glu plays a key role in reducing the self-association of the insulin molecule without greatly reducing its biological activity. This novel monomeric insulin might have potential applications in the clinic.

Mice with genetically altered GABA transporter subtype I (GAT1) expression show altered behavioral responses to ethanol.

It is widely accepted that the GABAergic system plays an important role in the action of ethanol in vivo. GABA transporter subtype 1 (GAT1) constructs high affinity reuptake sites in the CNS and regulates GABAergic transmissions. In this study, mice lacking the GAT1 were developed by homologous recombination. Both hetero- and homozygous GAT1 mutant mice were tested for ethanol, saccharin or quinine consumption, ethanol-conditioned place preference, ethanol-conditioned taste aversion, ethanol-simulated motor activity, and ethanol-induced sedation/hypnosis. The GAT1(-/-) mice showed decreased ethanol aversion and ethanol reward, and insensitivity to both the sedative/hypnotic and the motor stimulant effects of ethanol, along with increased avoidance of quinine preference and consumption. GAT1(+/-) mice showed significantly increased consumption of ethanol and saccharin, however, enhanced the rewarding and preference effect of ethanol, increased avoidance of quinine, and higher sensitivity to the motor stimulant effect of ethanol. These results demonstrate that GAT1, perhaps in a bi-directional way, modulates some behavioral effects of ethanol. The GAT1 mutant mice provided us a very useful model to investigate the mechanisms of ethanol action in vivo.

The quantitative classification and survey of sanitation of urban secondary water supply in Haidian district of Beijing / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the sanitary status of urban secondary water supply facilities in Haidian district of Beijing.</p><p><b>METHODS</b>Adopting the quantitative classification table drafted by the Bureau for Sanitation Inspection and Supervision of Haidian district, we carried quantitative classification (A, B, C grade) on all 1725 secondary water supply facilities in Haidian district for two times. At the same time, we collected 20 residential areas with stratified random sampling method. As the public points in the first quantitative classification, the effect of level publicity on changing the sanitary grade of the secondary water supply facilities were observed.</p><p><b>RESULTS</b>In the first two times of quantitative classification, A-level and B-level secondary water supply facilities took up 81.04% (1398/1725) and 89.04% (1536/1725) of all secondary water supply facilities respectively; the ratio of effective sanitary permits achieved 86.14% (1486/1725) and 92.35% (1593/1725) respectively; and the ratio of effective water quality test reports achieved 86.60% (1494/1725) and 97.10% (1675/1725) respectively. There were 52 secondary water supply facilities in 20 collected areas, including 8 A-level, 27 B-level and 17 C-level secondary water supply facilities before level publicity, and 19, 29 and 4 after level publicity. The impact of level publicity on changing the sanitary grade of the secondary water supply facilities was statistically significant (χ(2) = 12.60, P = 0.002).</p><p><b>CONCLUSION</b>The city secondary water supply facilities in Haidian district are overall in good sanitary conditions. Quantitative classification and level publicity can effectively improve the sanitary status of secondary water supply facilities.</p>