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ABSTRACT: Amyloid β protein (Aβ) is closely involved in the pathogenesis of Alzheimer's disease (AD), and one of the main strategies for AD treatment is antagonizing the neurotoxicity of Aβ or even clearing the Aβ deposited in the brain. The present study was aimed to observe the effects of intrahippocampal injection of Aβ(31-35) on the spatial learning and memory of rats by using Morris water maze technique, and explore the neuroprotective effects and possible mechanism of [Gly14]-humanin (HNG) against Aβ-induced deficits in learning behavior. The results showed that bilateral intrahippocampal injection of 2.0 nmol Aβ(31-35) significantly increased the mean traveled distance of rats in searching for the hidden underwater platform and decreased the distance percentage in the target quadrant in probe test after withdrawal of platform, whereas pretreatment with HNG (0.2 nmol and 2.0 nmol) suppressed Aβ(31-35)-induced increase in the traveled distance and decrease in swimming distance percentage. Application of Genistein (40 nmol), a specific tyrosine kinase inhibitor, almost completely blocked the antagonistic effects of HNG against Aβ(31-35). These results indicate that HNG can dose-dependently prevent against Aβ(31-35)-induced impairment in spatial learning and memory of rats, and the neuroprotective effects of HNG might involve the activation of endogenous tyrosine kinase pathway, suggesting that up-regulation of the tyrosine kinase signaling by using HNG might be of great significance for the improvement of cognitive function in AD.
Sheng li xue bao: [Acta physiologica Sinica] 12/2012; 64(6):625-32.
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ABSTRACT: The high density of senile plaques with amyloid beta protein (Aβ) and the loss of cholinergic neurons in the brain are the dominated pathological characteristics of Alzheimer's disease (AD). However, the active center of Aβ, especially the cholinergic mechanism underlying the Aβ neurotoxicity, is mostly unknown. This study examined the effects of different Aβ fragments on hippocampal long-term potentiation (LTP) and investigated its probable α7 nicotinic acetylcholine receptors (nAChRs) mechanism. The results show that: (1) intracerebroventicular injection of Aβ25-35 or Aβ31-35 significantly and similarly suppressed hippocampal LTP in CA1 region in rats; (2) choline, a selective α7 nAChR agonist, did not affect the LTP induction but enhanced LTP suppression induced by Aβ31-35; and (3) methyllycaconitine, a specific α7 nAChR antagonist, slightly suppressed hippocamal LTP but effectively prevented against Aβ31-35-induced LTP depression in the presence of Aβ31-35. These results indicate that: (1) the amino acid sequence 31-35 of the Aβ peptide might be a shorter active sequence in the full length molecule; (2) α7 nAChRs are required for the Aβ-induced suppression of hippocampal LTP. Thus, this study not only provides a new insight into the mechanism by which Aβ impairs synaptic plasticity but also strongly suggests that sequence 31-35 in Aβ molecule and α7 nAChRs in the brain might be potential therapeutic targets for the treatment of AD.
Synapse 05/2011; 65(11):1136-43. · 2.94 Impact Factor
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ABSTRACT: Effect of dosing powder activated carbon (PAC) on the characteristics of the sludge mixed liquor in membrane bioreactor (MBR) was investigated by parallel tests. And the reason that PAC mitigated membrane fouling was also explored. The results showed that PAC could decrease mixture viscosity and increase sludge particle size, which led to less trans-membrane pressure developing. Extracellular polymer substances (EPS) content, sludge specific resistance and cake layer resistance (R(c)) had a good correlation. Adding PAC could decrease EPS concentration, sludge specific resistance and then slow down the increase of R(c), which mitigated membrane fouling. Membrane pore blocking resistance (R(p)) increased exponentially with increasing of the soluble microbial products (SMP) concentration in the supernatant. Dosing PAC reduced the SMP concentration and slowed down the growth rate of R(p), which was helpful to mitigating membrane fouling. R(c) and R(p) increased along with the operation of MBRs and R(c)/R(f) (26.32% -63.16%) was always greater than R(p)/R(f) (7.89% -35.32%) which suggested the R(c) was the main factor in membrane fouling. Moreover, it was also found that controlling of dosing PAC on R(c) was better than it on R(p).
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 02/2011; 32(2):508-14.
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ABSTRACT: The two-chamber microbial fuel cells (MFCs) were constructed with excess sludge as the anodic substrate and CuSO4 solution as the catholyte. The start up method, degradation of the anodic sludge, removal of the Cu2+ and products on cathode were investigated in the study. The results of batch experiments showed that Cu2+ can be used as cathodic electron acceptors, e. g. a stable voltage output of 0.478 V and a maximum power density of 536 mW/m3 were obtained at external resistance of 1 000 omega and Cu2+ concentration of 6 400 mg/L. The Cu2+ contained in wastewater could be removed effectively by the MFC process, e. g. 97.8% of Cu2+ was removed in a MFC reactor at the end of 288 h with initial Cu2+ concentration of 1 000 mg/L and external resistance of 0 omega. The cathodic products depended on cathodic reducibility, most of Cu2+ was deposited as Cu2O and a small part as Cu4 (OH), 6SO4 with lower cathodic reducibility, metal copper deposited on the cathode with higher cathodic reducibility. Using excess sludge as anodic substrate could support the MFCs for long-term operation. The acclimation stage of the exoelectrogenic bacteria on the anode had an impact on MFC performance and cathodic reduction of Cu2+, and the stability of exoelectrogenic biofilm on anode could be determined by monitoring the anode potential. The MFC with excess sludge as anodic substrate can degrade organic matter in sludge and accomplish Cu(2+) -containing wastewater treatment and copper recovery simultaneously.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 01/2011; 32(1):179-85.
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ABSTRACT: In order to study the effect of O3 inactivating Giardia in water, different factors (CT value, pH, temperature, turbidity, organic content and inorganic ions) which might influence the inactivation were investigated by using fluorescence staining method. The results indicated that the whole process of O3 inactivating Giardia could be divided into two periods, the inactivated rate in log phase was significantly faster than it in the slow phase [k1 = (5.64 +/- 0.023) x 10(-1) mg x min, k2 = (2.72 +/- 0.002) x 10(-2) mg x min, k1 > k2]. When the turbidity was 0.1 to 20. 0NTU, temperature was 5 to 35 degrees C, pH was 6.0 to 9.0, HA content was 0.5 to 10.0 mg/L, the turbidity was lower, the higher inactivating ratio could be received. With the increasing of temperature, the inactivating effect was decreased. The ability of O3 inactivating Giardia was stronger under acidic condition than it was in alkali circumstance. When the reaction system contained higher concentration of organics, the competition reaction might take place between Giardia and organics with O3, which might reduce inactivation ratio. The sequence of affecting disinfectant ability of O3 was NO3- > None > SO4(2-) > HCO3-, while inorganic cations (Ca2+, Mg2+ and Cu2+) promoted the inactive reaction to a certain extent. If the CT value of O3 was more than 15.0 min x mg/L, the ratio of inactivation could exceed 99.0% during disinfecting drinking water.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 06/2010; 31(6):1459-63.
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ABSTRACT: The endocrine disrupter Atrazine was oxidized by O3/H2O2 system and the products were analyzed to assess the degradation efficiency of Atrazine. When it's initial content was 2 mg/L and O3 dosage was 7.5 mg/L, Atrazine was removed about 27.2% after 5 minutes. Under the same condition, H2O2/O3 molar ratio was 0.75, Atrazine maximum removal rate reached 96.5%, which suggested that Atrazine could be degraded by O3/H2O2 system effectively. Ion Chromatography (IC) analysis showed that concentrations of chloride and nitrate ions were increasing along with the Atrazine content decreasing. Gas Chromatography-Mass spectrometry (GC-MS) and Liquid Chromatography-Mass spectrometry chromatograms (LC-MS) analyzing illuminated the existence of de-ethyl-atrazine, de-isopropyl-atrazine and de-chloro-atrazine, which indicated the Atrazine could not be destroyed completely by O3/H2O2 system. Consequently, it should be combined with GAC (Granular Activated Carbon) or other techniques while used as primary treatment unit or emergency measure.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 06/2009; 30(5):1425-9.
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ABSTRACT: The endocrine disrupter simazine was oxidized by O3/H2O2 and the reactive productions was analyzed by chromatography to assess the degradation efficiency of Simazine. The initial content of Simazine 2 mg/L was removed about 87.1% by O3H2O2 system when the O3 was dosed as 10.0 mg/L, the H2O2/O3 molar ratio was 0.70, the temperature was 26 degrees C and pH 7-8, which indicated Simazine could be conveniently removed by O3/H2O2 system in ordinary reactive condition. The simazine removal ratio in tap water was 10% more than it in purified water up to 86.9%. The removal of simazine was decreased when the content of humic acid (HA) was high, whereas it was increased while low content HA in water. Also, the removal efficiency was inhabited by hydrogen carbonate fairly. The deethyl-simazine (DES) was trapped by Gas Chromatography Mass Spectrum(GC-MS) which was also certificated by analyzing the Liquid Chromatography Mass Spectrum (LC-MS) of the products. The Ion Chromatography spectrum showed the existing of de-chloro-procedure and breakage of triazine ring. Which indicated the oxidizability of O3/H2O2 system was fairly strong.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 08/2008; 29(7):1914-8.
