Influence of chronic intermittent hypoxia on growth associated protein 43 expression in the hippocampus of young rats

This study aimed to explore the pathological change to hippocampal neurons and the expression of growth associated protein 43 in 21-day-old young rats following chronic intermittent hypoxia.Hematoxylin-eosin staining results showed varying degrees of degeneration and necrosis in hippocampal neurons depending on the modeling time.Immunohistochemistry revealed that growth associated protein 43 expression in young rats following chronic intermittent hypoxia decreased,but that levels were still higher than those of normal rats at each time point,especially 4 weeks after modeling.During 1-5 weeks after modeling,a slow growth in rat weight was observed.Experimental findings indicate that chronic intermittent hypoxia may induce growth dysfunction and necrosis of hippocampal neurons,as well as increase the expression of growth associated protein 43 in young rats.

Changes in plant species composition and diversity of alpine Kobresia (Kobresia pygmaea) steppe meadow at different stages of desertification in the North Tibetan plateau

The impacts of desertification on the vegetation composition, structure, and species diversity of alpine Kobresia steppe meadow were evaluated in an area of severe desertification in Anduo County, Tibet Autonomous Region, northern China. We investigated and analyzed the floristic features of communities at four different stages of desertification (slight desertification [SLD], moderate desertification [MD], severe desertification [SD], and very severe desertification [VSD]). The composition and structure of the alpine Kobresia steppe meadow at the SLD site differed significantly from that at the MD, SD, and VSD sites. Species that were more drought resistant and inedible by livestock were the dominant species at the SD site. No plants were found in the shifting dunes of the VSD site. Species diversity also decreased with increasing desertification. The SLD site had the largest mean number of species and individuals and the largest richness index; the MD grassland had the largest Shannon-Wiener index and evenness index, but the smallest Simpson's index. The vegetation cover declined from 91.8% to 34.8% as desertification increased from SLD to SD, and reached 0% in VSD areas with shifting dunes.

Impairment of cognitive function and reduced hippocampal cholinergic activity in a rat model of chronic intermittent hypoxia

The present study established a rat model of chronic intermittent hypoxia (CIH) to simulate obstructive sleep apnea syndrome.CIH rats were evaluated for cognitive function using the Morris water maze,and neuronal pathology in the hippocampus was observed using hematoxylin-eosin staining.In addition,hippocampal choline acetyl transferase (ChAT) and nicotinic acetylcholine receptor (nAChR) expression was determined by immunohistochemistry.Our results revealed necrotic hippocampal neurons,decreased ChAT and nAChR expression,as well as cognitive impairment in CIH rats.These results suggest that hippocampal neuronal necrosis and decreased cholinergic activity may be involved in CIH-induced cognitive impairment in rats.

Effect of Ginsenoside Rbl on Expressive Proteome of Rat Neurons

[Objective] This study aimed to explore the effect of ginsenoside Rbl on expressive proteome of rat neurons by technologies of proteomics, bioinformatics and MS peptide fingerprinting. [Method] Rat neurons were cultured conventionally and randomly separated into two groups. The experimental group was treated with 5 μg/ml Rbl for 20 min, while control group was added with the same amount of medium. After cell lysis, the whole-cell protein was extracted. Two-dimensional electrophoresis (2-DE) was used to separate the extracts. Differential expression of proteome between the two groups was analyzed by using ImageMaster 2D Platinum v5.0 software and the two protein spots expressed differently were selected for differential identification with MALDI-TOF-MS. [Result] Based on the matching and comparative analysis of the protein spots, 418 protein spots were detected in experimental group, including 226 protein spots with differently expressive levels; according to the mass spectrometry, the two ginsenoside Rbl-related and differentially-expressed protein spots were identified as cytochrome P-450 and phosducin-like protein, and both of them were phosphorylated proteins. [Conclusion] This study showed that the functions of those identified proteins were involved in signal transduction, suggesting that the effect of ginsenoside Rbl on expressive proteome of rat neurons might be related to the corresponding signal transduction networks.

miR164c and miR168a regulate seed vigor in rice^∞

Micro RNAs(miRNAs)are key regulators of gene expression in many important biological processes of plants.However,few miRNAs have been shown to regulate seed vigor.Here,we conducted microarray assays to analyze miRNA expression levels in seeds of the rice(Oryza sativa L.)cultivar ZR02.Results showed significant differences in the expression of 11 miRNAs between artificially aged and untreated control seeds.Among these,osa-miR164c was transcriptionally upregulated,while osamiR168 a was downregulated in artificially aged seeds;this was verified by quantitative real-time PCR analysis.Under the same aging condition,osa-miR164c overexpression in OE164c transgenic seeds and osa-miR168a silencing in MIM168a transgenic seeds of the rice cultivar Kasalath led to lower germination rates,whereas osa-miR164c silencing Rin MIM164c and osa-miR168a overexpression in OE168a resulted in higher seed germination rates compared with wild-type seeds.Meanwhile,changes in cytomembrane permeability of seeds and in the expression level of osa-miR164c target genes(OsPM27 and OsPSK5)and osamiR168a target genes(OsAGO1 and OsPTR2)under aging conditions coincided with changes in seed vigor induced by osa-miR164c and osa-miR168 a.Thus,genetic manipulation of miRNAs has important implications in the development of crop cultivars with high vigor and extended life span of seeds.

The trajectory parameters analysis of saltating sand grains driven by wind

The study of trajectory parameters of saltating sand grains is of great importance to forming the kinematic theory of wind-sand current. By establishing the simplified theoretical pattern and probing into the relationship between lift-off angle (α) and landing angle (β), relationship between the ratio of saltation length ( L) to maximum height (H) and lift-off angle as

The varying fetch effect of aeolian sand transport above a gobi surface and its implication for gobi development process

The Gobi deserts are important landscapes and major sandstorm source areas in arid northwestern China.Unsaturated sand flow and decreasing sand supply capacity is well known as the basic characteristics of gobi surface,but relatively little attention has been paid to the fetch effect of sand transport which is closely related to sand supply and indicative of wind erosion process in gobi.Using a field experiment,we investigated the spatial and temporal variations on a manually disturbed gobi surface downwind a sand-blocking belt and a sand-fixing belt by measuring the sand transport rate and the height profile of flux density at different fetch lengths during a sequence of wind erosion events.Results showed that the sand supply capacity determined the critical fetch length(Lc)for the sand transport rate so that the fetch effect varied with wind erosion proceeding due to depletion of erodible material.The height profile of flux density above the surface followed two distributions:an exponential decrease with increasing height,which commonly occurred above the newly treated gobi surface during the early wind erosion events;or a Lorentzian distribution with a peak flux at a certain height,which often happened in the later wind erosion events.The varying fetch effect,decreasing sand transport rates,and the nonerodible area expanded downwind are an epitome of the gobi development and expansion process from the perspective of wind erosion.