[Chronic sleep deprivation exacerbates cognitive and pathological impairments in APP/PS1/tau triple transgenic Alzheimer's disease model mice].

Sleep exerts important functions in the regulation of cognition and emotion. Recent studies have found that sleep disorder is one of the important risk factors for Alzheimer's disease (AD), but the effects of chronic sleep deprivation on the cognitive functions of AD model mice and its possible mechanism are still unclear. In the present study, 8-month-old male APP/PS1/tau triple transgenic AD model (3xTg-AD) mice and wild type (WT) mice (n = 8 for each group) were subjected to chronic sleep deprivation by using the modified multiple platform method, with 20 h of sleep deprivation each day for 21 days. Then, open field test, elevated plus maze test, sugar water preference test, object recognition test, Y maze test and conditioned fear memory test were performed to evaluate anxiety- and depression-like behaviors, and multiple cognitive functions. In addition, the immunohistochemistry technique was used to observe pathological characteristics in the hippocampus of mice. The results showed that: (1) Chronic sleep deprivation did not affect anxiety- (P = 0.539) and depression-like behaviors (P = 0.874) in 3xTg-AD mice; (2) Chronic sleep deprivation exacerbated the impairments of object recognition memory (P < 0.001), working memory (P = 0.002) and the conditioned fear memory (P = 0.039) in 3xTg-AD mice; (3) Chronic sleep deprivation increased amyloid ß (Aß) deposition (P < 0.001) and microglial activation (P < 0.001) in the hippocampus of 3xTg-AD mice, without inducing abnormal tau phosphorylation and neurofibrillary tangles. These results indicate that chronic sleep deprivation exacerbates the impairments of recognition memory, working memory and conditioned fear memory in 3xTg-AD mice by aggravating Aß deposition and the excessive activation of microglia in the hippocampus.

[Evaluation for heavy metal pollution of soil and herb from main producing area of Phellodendron amurense in China].

In order to evaluate the heavy metal potential pollution of soil and medicinal materials in main producing area of Phellodendron amurense, we collected 32 soil samples and 32 herb samples from northeast and north of China covering four provinces. In this study, the detection of heavy metal contents was conducted by ICP emission spectroscopy and atomic fluorescence spectrometry. The results showed that the soil from all areas of Ph amurense generally reached the national standard. As, Hg, Cr, Cd, Pb and Cu content of herb samples met the requirtment of the national standard except Hg content exceeding standard slight in a few samples. The reason of excessive Hg was the ability of Hg accumulation in Ph. amurense and atmospheric environment was polluted. So, national standard and Good Agricultural Practice (GAP) must be carried out severely in Ph. amurense resources production.

Selective orexin 1 receptor antagonist SB-334867 aggravated cognitive dysfunction in 3xTg-AD mice.

Cognitive dysfunction is the main clinical manifestation of Alzheimer's disease (AD). Previous research found that elevated orexin level in the cerebrospinal fluid was closely related to the course of AD, and orexin-A treatment could increase amyloid ß protein (Aß) deposition and aggravate spatial memory impairment in APP/PS1 mice. Furthermore, recent research found that dual orexin receptor (OXR) antagonist might affect Aß level and cognitive dysfunction in AD, but the effects of OX1R or OX2R alone is unreported until now. Considering that OX1R is highly expressed in the hippocampus and plays important roles in learning and memory, the effects of OX1R in AD cognitive dysfunction and its possible mechanism should be investigated. In the present study, selective OX1R antagonist SB-334867 was used to block OX1R. Then, different behavioral tests were performed to observe the effects of OX1R blockade on cognitive function of 3xTg-AD mice exhibited both Aß and tau pathology, in vivo electrophysiological recording and western blot were used to investigate the potential mechanism. The results showed that chronic OX1R blockade aggravated the impairments of short-term working memory, long-term spatial memory and synaptic plasticity in 9-month-old female 3xTg-AD mice, increased levels of soluble Aß oligomers and p-tau, and decreased PSD-95 expression in the hippocampus of 3xTg-AD mice. These results indicate that the detrimental effects of SB-334867 on cognitive behaviors in 3xTg-AD mice are closely related to the decrease of PSD-95 and depression of in vivo long-term potentiation (LTP) caused by increased Aß oligomers and p-tau.

Chronic sleep deprivation exacerbates cognitive and synaptic plasticity impairments in APP/PS1 transgenic mice.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive deficits. Sleep deprivation (SD) could lead to memory deficits, and it was a candidate risk factor for AD. However, the effects of chronic SD on the cognitive functions of AD model mice and its possible mechanism are still unclear. In the present study, 8-month-old male APP/PS1 transgenic mice and wild type (WT) littermates were subjected to chronic SD by using the modified multiple platform method (MMPM), with 20 h of SD each day for 21 days. Then, the effects of chronic SD on cognitive functions in APP/PS1 mice were tested by using behavioral tests, the potential mechanisms were investigated by in vivo electrophysiological recording, western blot and immunochemistry. The results showed that chronic SD obviously aggravated the cognitive impairments, exacerbated in vivo hippocampal long-term potentiation (LTP) suppression, reduced the expression level of PSD95, increased amyloid-ß (Aß) protein deposition and overactivated microglia in the hippocampus of APP/PS1 mice. These results indicate that chronic SD exacerbates the cognitive deficits in APP/PS1 mice by accelerating the development of AD pathologies, reducing the expression of PSD95 and aggravating the LTP suppression in hippocampus. At the same time, chronic SD also impaired cognitive functions and synaptic plasticity in WT mice through down-regulating the level of PSD95 and activating microglia. These findings further clarify the electrophysiological and molecular mechanisms of exacerbated cognitive deficits in AD caused by chronic SD.

Overexpression of the ChVDE gene, encoding a violaxanthin de-epoxidase, improves tolerance to drought and salt stress in transgenic Arabidopsis.

To investigate the protective mechanism of violaxanthin de-epoxidase (VDE) zeaxanthin in Cerasus humilis under drought and salt-stress conditions, we cloned the entire cDNA sequence of ChVDE from C. humilis and generated ChVDE-overexpression (OE) and ChVDE-complementation (CE) Arabidopsis plants. The open reading frame of ChVDE contained 1,446 bp nucleotides and encoded 481 amino acids. The ChVDE showed the highest similarity with those of Camellia sinensis and Citrus sinensis. Subcellular localization analysis showed that ChVDE was located in the chloroplasts. OE plants showed stronger root growth and higher levels of total chlorophyll as compared to WT and VDE mutant (npq1-2) plants. Moreover, the relative de-epoxidation state of the xanthophyll cycle pigments (A + Z)/(V + A+Z) was higher in OE plants than in the controls. OE plants had enhanced photosynthetic rates, respiration rates, and transpiration rates compared with the WT or npq1-2 plants after drought or salt treatment. Collectively, our results demonstrate that ChVDE plays a positive role in both drought and salt tolerance.

Comparative analysis of ESTs in response to drought stress in chickpea (C. arietinum L.).

Chickpea (Cicer arietinum L.) is an important pulse crop grown mainly in the arid and semi-arid regions. To identify the water-stress-induced genes, two non-normalized cDNA libraries were constructed from the seedling leaves of a drought-tolerant chickpea cultivar under PEG-treated and -nontreated conditions. About 2500 clones from each library were selected randomly for sequencing analysis. Based on IDEG6 online software analysis, 92 genes were differentially expressed, and these genes were involved in diverse biological progresses, such as metabolism, transcription, signal transduction, protein synthesis and others. Most of the up-regulated genes were related to drought tolerance, and the down-regulated genes were mainly involved in photosynthesis. The differential expression patterns of five functional unigenes were confirmed by quantitative real-time PCR (qPCR). The results will help in understanding the molecular basis of drought tolerance in chickpea.

A NAC transcription factor gene of Chickpea (Cicer arietinum), CarNAC3, is involved in drought stress response and various developmental processes.

NAC transcription factors have been found to play important roles in plant development and responses to environmental stresses. Based on two cDNA libraries constructed from the PEG-treated and -nontreated seedling leaves of chickpea, a NAC gene, CarNAC3, was isolated and characterized. The results indicated that CarNAC3 contained 285 amino acids and had a conserved NAC domain. It was localized in the nucleus and possessed trans-activation activity in the C-terminus. Phylogenetic analysis showed that CarNAC3 belonged to the NAP (NAC-like, activated by APETALA3/PISTILLATA) subgroup of the NAC protein family. CarNAC3 exhibited organ-specific expression and its induction was strongly dependent on leaf age. CarNAC3 showed differential expression patterns during seed development and germination, and could be significantly induced by drought stress, abscisic acid (ABA), ethephon (Et) and indole-3-acetic acid (IAA), but was inhibited by N-6-benzyl-adenine (6-BA). Our data suggest that CarNAC3 may be a transcriptional activator involved in drought stress response and various developmental processes.