不同生态型芦苇种群对盐胁迫的生长和光合特性

土壤盐渍化是影响我国土壤利用效率的主要因素之一,芦苇是改良土壤盐渍化的良好实验材料,但芦苇有着多种的生态型,比较各生态型芦苇的耐盐差异成为亟待解决的问题。通过设置淡水(0.00%)与加盐(质量浓度2.00%)处理控制实验,测量芦苇的生长指标和光合指标,比较河口型芦苇与内陆型芦苇耐盐性,寻找合适生态型的芦苇作为改良土壤盐渍化的生物材料。在实验中,与淡水条件相比,加盐(2.00%)处理条件下,河口型芦苇和内陆型芦苇的株高(height)、蒸腾速率(E)均显著性下降,但是两种生态型的芦苇的水分利用效率(WUE)明显提高;河口型的芦苇相对生长速率(RGR)和气孔导度(Gs)都明显高于内陆型芦苇。在淡水环境中,河口型芦苇的相对生长速率(RGR)和净光合速率(A)都显著性地高于内陆型芦苇。结果表明两种生态型的芦苇在进化过程中存在一定程度上的分化,盐胁迫会抑制两种芦苇的生长,两种生态型芦苇的相对生长速率和气孔导度在盐胁迫下出现明显地差异,表明两种生态型的芦苇对盐度的响应机制有所差异。相比于内陆型芦苇,河口型芦苇有着更强的耐盐性,内陆型及河口型芦苇的表型性状差异主要是由于其原生境的差异所决定的。     

Polyhydroxylated fullerene C60(OH)44 suppresses intracellular lipid accumulation together with repression of intracellular superoxide anion radicals and subsequent PPARγ2 expression during spontaneous differentiation of OP9 preadipocytes into adipocytes

Reactive oxygen species has been suggested to be one of the key factors associated with the development of obesity. During spontaneous differentiation of mouse stromal preadipocytes OP9 into adipocytes, intracellular superoxide anion radicals (O (2) (-.) ) level markedly increases and is accompanied by a significant elevation of intracellular lipid accumulation. This differentiation-dependent increase in intracellular O (2) (-.) level positively correlated with the intracellular augmentation of the lipid level. Super-highly hydroxylated fullerene (SHH-F; C(60)(OH)(44)), a novel polyhydroxylated fullerene derivative, quenched intracellular O (2) (-.) , and lipid accumulation to 38.7 and 42.7 % of that in the control, respectively. By thin-layer chromatographic analysis of extracted cellular lipid components, SHH-F clearly decreased the triglycerides ratio in the whole lipid droplet fraction, but scarcely influenced other lipids components. PPARγ2 expression, which plays a key role in regulating adipogenic differentiation, was significantly suppressed by SHH-F at the late stage of differentiation, with unaltered PPARγ1 expression. The intracellular superoxide anion radical augmentation preceded expression of PPARγ2, strongly suggesting that the primary O (2) (-.) generation was closely associated with lipid accumulation and subsequent PPARγ2 induction. These results indicate that SHH-F suppresses intracellular lipid accumulation, particularly in lipid droplets, and decreases O (2) (-.) level and subsequent PPARγ2 upregulation during spontaneous differentiation of OP9 preadipocytes into adipocytes.     

Abundance, marker development and genetic mapping of microsatellites from unigenes in Brassica napus

Rapeseed (Brassica napus) is the second most important oil crop in the world after soybean. The repertoire of simple sequence repeat (SSR) markers for rapeseed is limited and warrants a search for a larger number of polymorphic SSRs for germplasm characterization and breeding applications. In this study, a total of 5,310 SSR-containing unigenes were identified from a set of 46,038 B. napus unigenes with an average density of one SSR every 5.75?kb. A set of 1,000 expressed sequence tag (EST)-SSR markers with repeat length ??18?bp were developed and tested for their ability to detect polymorphism among a panel of six rapeseed varieties. Of these SSR markers, 776 markers detected clear amplification products, and 511 displayed polymorphisms among the six varieties. Of these polymorphic markers, 195 EST-SSR markers, corresponding to 233 loci, were integrated into an existing B. napus linkage map. These EST-SSRs were randomly distributed on the 19 linkage groups of B. napus. Of the mapped loci, 166 showed significant homology to Arabidopsis genes. Based on the homology, 44 conserved syntenic blocks were identified between B. napus and Arabidopsis genomes. Most of the syntenic blocks were consistent with the duplication and rearrangement events identified previously. In addition, we also identified three previously unreported blocks in B. napus. A subset of 40 SSRs was used to assess genetic diversity in a collection of 192 rapeseed accessions. The polymorphism information content of these markers ranged from 0.0357 to 0.6753 with an average value of 0.3373. These results indicated that the EST-SSR markers developed in this study are useful for genetic mapping, molecular marker-assisted selection and comparative genomics.     

Analysis of the neutral polysaccharide fraction of MCP and its inhibitory activity on galectin-3

The pH-modified citrus pectin (MCP) has been demonstrated to inhibit galectin-3 in cancer progression. The components and structures of MCP related to this inhibition remained unknown. In this paper, we fractionated MCP on DEAE-cellulose column into a homogenous neutral fraction MCP-N (about 20?kDa) and a pectin mixture fraction MCP-A (wide molecular distribution on Sepharose CL-6B chromatography). Both MCP-N and MCP-A inhibited hemagglutination mediated by galectin-3 with minimum inhibition concentration (MIC) 625 and 0.5?μg/ml, respectively. MCP-N was identified to be a type I arabinogalactan (AG-I) with a main chain of β-1→4-galactan. MCP-N was digested by α-L-arabinofuranosidase to give its main chain structure fraction (M-galactan, around 18?kDa), which was more active than the original molecule, MIC 50?μg/ml. The acidic degradation of M-galactan increased the inhibitory activity, MIC about 5 times lower than M-galactan. These results above showed that the functional motif of the β-1→4-galactan fragment might lie in the terminal residues rather than in the internal region of the chain. Therefore, MCP-N and its degraded products might be developed to new potential galectin-3 inhibitors. This is the first report concerning the fractionation of MCP and its components on galectin-3 inhibition. The information provided in this paper is valuable for screening more active galectin-3 inhibitors from natural polysaccharides.     

基于解释结构模型的煤电一体化开发生态环境累积效应识别

为了对煤电一体化开发的生态环境累积效应进行识别与分析,从煤电一体化开发的主要开采建设活动、土壤环境、水资源、大气环境、生物、景观、生态7方面共筛选出29个生态环境因子,综合文献调查、专家调查问卷与访谈等方法,分析了各生态环境因子之间的相互作用关系.运用解释结构模型(ISM)分析了各因子间的关联关系与层次结构,揭示了不同开发建设活动产生累积效应的途径.结合具体的评价与管理需求,提出了煤电一体化开发生态环境累积效应研究与评估整体框架.研究结果可以为煤电一体化开发的规划与管理提供一定的理论基础与技术手段.     

Automatic non-proliferative diabetic retinopathy screening system based on color fundus image

Background

Non-proliferative diabetic retinopathy is the early stage of diabetic retinopathy. Automatic detection of non-proliferative diabetic retinopathy is significant for clinical diagnosis, early screening and course progression of patients.

Methods

This paper introduces the design and implementation of an automatic system for screening non-proliferative diabetic retinopathy based on color fundus images. Firstly, the fundus structures, including blood vessels, optic disc and macula, are extracted and located, respectively. In particular, a new optic disc localization method using parabolic fitting is proposed based on the physiological structure characteristics of optic disc and blood vessels. Then, early lesions, such as microaneurysms, hemorrhages and hard exudates, are detected based on their respective characteristics. An equivalent optical model simulating human eyes is designed based on the anatomical structure of retina. Main structures and early lesions are reconstructed in the 3D space for better visualization. Finally, the severity of each image is evaluated based on the international criteria of diabetic retinopathy.

Results

The system has been tested on public databases and images from hospitals. Experimental results demonstrate that the proposed system achieves high accuracy for main structures and early lesions detection. The results of severity classification for non-proliferative diabetic retinopathy are also accurate and suitable.

Conclusions

Our system can assist ophthalmologists for clinical diagnosis, automatic screening and course progression of patients.

     

Structure,composition and mechanical properties of the silk fibres of the egg case of the Joro spider, <Emphasis Type="Italic">Nephila clavata</Emphasis> (Araneae,Nephilidae)

The silk egg case and orb web of spiders are elaborate structures that are assembled from a number of components. We analysed the structure, the amino acid and fibre compositions, and the tensile properties of the silk fibres of the egg case of Nephila clavata. SEM shows that the outer and inner covers of the egg case consist of thick, medium and thin silk fibres. The silk fibres of the outer cover of the egg case are probably produced by the major and minor ampullate glands. The silk fibres of the inner cover of the egg case from cylindrical glands appears to be distinct from the silk fibres of the major ampullate glands based on their micro-morphology, mole percent amino acid composition and types, and tensile behaviour and properties. Collectively, our investigations show that N. clavata uses silk fibres from relatively few glands in varying combinations to achieve different physical and chemical properties (e.g., color, diameter, morphology and amino acid composition) and functional and mechanical properties in the different layers of the egg case.