香蕉TGA转录因子家族的鉴定及枯萎病菌胁迫下的表达分析

尖孢镰刀菌（Fusarium oxysporum f. sp. Cubense, Foc）引起的香蕉枯萎病是我国香蕉的主要病害之一,严重影响香蕉的产量和品质。TGA防御反应基因在香蕉应对尖孢镰刀菌胁迫的应答转录调控过程中至关重要。本研究以拟南芥TGA转录因子家族成员蛋白为查询序列,在香蕉基因组数据库中Blast筛选出TGA转录因子家族成员,并对该家族成员进行生物信息学分析。共鉴定得到9个香蕉TGA家族成员,分别命名为MaTGA1~MaTGA9;香蕉TGA家族蛋白富含酸性氨基酸,大部分蛋白以α螺旋为主;亚细胞定位主要在细胞核内。进化树分析表明,香蕉MaTGA转录因子家族的9个成员可分为Class Ⅰ和Class Ⅱ两类,基因结构及功能结构域的分布情况也呈现出高度一致。进一步通过RT-qPCR分析发现,MaTGA2、MaTGA3和MaTGA8在香蕉枯萎病菌侵染后的‘威廉斯’（易感病）及‘南天黄’（抗病）中均显著下调表达,MaTGA1、MaTGA6、MaTGA7和MaTGA9均呈现先下降后上升的趋势;然而MaTGA4和MaTGA5仅在‘威廉斯’中上调表达,以上结果表明MaTGA2、MaTGA3和MaTGA8在香蕉抗枯萎病中发挥重要的生物学功能。本研究结果为香蕉TGA转录因子功能挖掘奠定理论基础。     

基于时间序列分析并预测三峡库区局地环境温度的变化

利用湖北秭归三峡库首典型区的气象监测资料,采用时间序列分析和自回归积分滑动平均模型（ARIAM）方法,对三峡库区2001-2015年局地环境温度变化进行趋势和预测分析,以探讨三峡工程蓄水对库区局地气候环境变化的影响。结果表明,研究区域局地气温和地温的时间序列为季节性非平稳时间序列,年际月平均气温峰值在7月（29.0℃）,低谷在1月（6.0℃）;研究期内局地平均气温在2003年降至17.8℃,2007年稳定升至18.3℃;2011年持续降至的17.1℃,之后稳定升至2013年的17.9℃。平均地温在2005年升至21.2℃,2008年持续降至19.4℃,后期在2013年稳定升至20.1℃。分析结果显示,在2003年蓄水前后三峡库首典型区局地环境温度呈现一定程度年际波动,但不存在显著单一的变化趋势,说明在研究期15a内三峡工程蓄水对研究区域的局地环境温度未产生显著影响。用ARIMA模型获得了气温和地温的最佳预测模型,2015年预测值与监测值的符合程度良好,可进一步利用该地区长期监测数据对模型进行优化和应用。     

微胶囊红磷膨胀型阻燃剂对环氧树脂的阻燃研究

研究了微胶囊红磷膨胀型阻燃剂的组成、含量对环氧树脂阻燃和力学性能的影响规律.试验结果表明:当膨胀型阻燃剂3组份(微胶囊红磷、季戊四醇和三聚氰胺)的质量比为1.46:0.34: 3.15,添加量为30%时,阻燃环氧树脂可以获得较好的阻燃性能并对力学性能影响较小.热重分析表明膨胀型阻燃剂可以显著提高环氧树脂的高温残炭量.残炭的数码照片和扫描电镜照片表明,膨胀型阻燃剂可以在环氧树脂的表面生成致密的膨胀炭层而对内部基材起到隔热、隔氧,从而提高了环氧树脂的阻燃效果.     

RT-PCR法克隆广谱抗病基因TGA2及其蛋白表达载体构建

本试验采用Trizol Reagent提取拟南芥总RNA,设计相关引物,采用反转录PCR方法克隆TGA2转录因子;利用酶切连接方法,将该基因正向导入蛋白表达载体.经过相关检验,TGA2转录因子连接到pMXB10载体内含肽(Intein)的N端,成功构建包含TGA2转录因子的pMXB10-TGA2蛋白表达载体.     

Effects of storage on the physico-chemical properties of corn tortillas prepared with glycerol and salt

Corn tortillas have a short shelf life due to increased firmness and microbial spoilage. Commercial corn tortillas use carboxymethyl cellulose (CMC) to delay staling; however this gum is expensive when compared to the rest of the tortilla ingredients. Glycerol has been added to bread and wheat tortillas to increase pliability and salt has been shown to mask the flavor of glycerol in corn tortillas. The possibility to reduce staling in corn tortillas by adding glycerol/salt as an alternative to CMC was investigated by monitoring changes in physico-chemical properties during 2 weeks of storage at 25 °C. Molecular and macroscopic changes were followed using thermal and mechanical analysis. During storage an increase in amylopectin recrystallization was observed in all samples. The “freezable” water content of all tortillas decreased over the first 3–5 days of storage with an increase after 7 days, while moisture content and water activity remained constant. Glycerol/salt tortillas exhibited a sharper transition region in the DMA temperature scan suggesting a more homogenous sample. CMC tortillas were significantly stiffer than glycerol tortillas after 14 days of storage. Glycerol/salt combinations may offer at least a partial replacement for CMC since it helped control the stiffness, water homogeneity and distribution during storage.     

Effect of curdlan on the quality of frozen-cooked noodles during frozen storage

Frozen-cooked noodles (FCN) and its components undergo quality changes during frozen storage, such as reduced textural and cooking qualities, weakened gluten network, and damaged starch properties; thus, storage condition is a critical factor affecting the final quality of FCN. In this study, in view of the thermoirreversible high-strength gel property (at ≥ 80 °C) of curdlan, strong hydrophilicity, and freeze-thawed stability of high-strength gel prepared from curdlan powder, the effect of curdlan on the quality of FCN during frozen storage was first evaluated. The results showed that curdlan was effective in reducing cooking loss, enhancing water absorption, and improving textural properties of FCN; the improving effect presented a trend of first increasing and then decreasing with the amount of increasing curdlan (0.1%–0.9%); and the addition of 0.5% curdlan was most effective in improving the quality of FCN. Thermal gravimetric analysis indicated that curdlan enhanced thermal stability of FCN, implying curdlan could strengthen the gluten network. Meanwhile, structural observations revealed that, during frozen storage, FCN with added curdlan exhibited a more continuous and compact gluten network accompanied with more uniform and smaller ice crystals. Thus, curdlan is desirable to be used as a novel gum in FCN to provide specific functionality and minimize the negative effect of frozen storage. This study provides new insights into the quality improvement of FCN and further expands the application potential of curdlan in food industry.     

生物质醇解重质油燃烧动力学研究

在热重分析仪上研究马尾松、桉木和麦秸秆的醇解重质油的燃烧过程及其动力学特性。结果发现,这3种重质油燃烧过程均可分为3个阶段:1)室温到300℃,为小分子有机物挥发阶段;2)300～480℃,为挥发分析出与燃烧阶段;3)480℃以上,为固定碳燃烧与燃尽阶段。动力学计算结果表明,这3个阶段都符合一级反应过程。同时,麦秸秆醇解重质油快速燃烧阶段(300～480℃)活化能最低,对应的失重速率最大,为0.188%/min,且着火温度最低,为405℃,因而其最易于燃烧。     

Influence of wheat streak mosaic virus infection on phenylpropanoid metabolism and the accumulation of phenolics and lignin in wheat

Wheat plants infected with wheat streak mosaic virus were studied for their physiological response to infection. Previous histological data suggest that wheat streak mosaic virus-induced deposits of phenolic nature are present along the bundle sheath and mesophyll cell walls. In this study, we examined this phenomenon further by analysis of phenolic compounds and enzymes involved in their synthesis. In infected plants, the amounts of free and wall-bound phenolic compounds increased slightly, and chromatography showed that the type of free phenolic compounds present had changed. The amount of lignin did not change due to infection. Enzyme assays showed that while phenylalanine ammonia lyase and tyrosine ammonia lyase activities decreased as they do in healthy plants, cinnamyl alcohol dehydrogenase activity stayed high throughout infection. In addition, peroxidase activities in infected plants decreased around the time that the leaves ceased to expand. These results suggest that the general phenylpropanoid pathway is stimulated upon infection, but that lignification is not.     

Preliminary Notes on Equine Tissue Transglutaminase Serology and A Case of Equine Gluten-Sensitive Enteropathy and Dermatitis in an 11-Year-Old Dutch Warmblood Horse

It has been suggested that gluten may play a role in equine inflammatory small bowel disease (ISBD). Previous work showed an association between equine gluten-sensitive enteropathy and IgA antibodies to tissue transglutaminase (TGA) in serum. The purpose of this study is to investigate the prevalence of IgA antibodies to TGA in a group of healthy non–gluten-free sport ponies and to present a case of tentative gluten-sensitive enteropathy and dermatitis in a horse. Blood samples were obtained from 40 healthy jumping ponies. The ponies comprised 12 mares, 8 stallions, and 20 geldings with an average age of 9.0 ± 3.8 years (±SD; range 3–19 years). Sera were tested for IgA antibodies against human recombinant TGA. Significance (P < .05) of the correlation between TGA titer and age in these ponies was assessed using Pearson test (two tailed). In addition, to further illustrate tentative equine gluten-sensitive enteropathy and dermatitis, the clinical course in an 11-year-old Dutch Warmblood sport horse gelding has been described. The average TGA titer was 21.4 ± 13.6 AU/mL (range 2–65 AU/mL). There was a significant (P = .013) correlation (r = 0.389) between age and TGA titer in ponies. One of the 40 ponies (2.5%) showed an elevated TGA titer. An elevated TGA titer decreased after a gluten-free ration for 3 months in an 11-year-old Warmblood gelding with a tentative diagnosis of ISBD associated with full remission of the generalized skin reaction. To our best knowledge, this is the first study assessing TGA antibodies in sera from healthy non–gluten-free ponies and showing a correlation with age. The presented case could be the first one of a horse with a tentative diagnosis of gluten-sensitive enteropathy combined with dermatitis. Given the reported findings, this study warrants further investigations into gluten-sensitive enteropathy and dermatitis in individual horses affected with ISBD.