Integrin-alphavbeta6, a putative receptor for foot-and-mouth disease virus, is constitutively expressed in ruminant airways.

Evolved functions of integrin-alpha(v)beta(6) include roles in epithelial cell-extracellular matrix protein interactions and in the binding and activation of latent TGF-beta(1). Integrin-alpha(v)beta(6) is also exploited as a receptor by foot-and-mouth disease virus (FMDV) and may play a significant role in its transmission and pathogenesis. The ovine beta(6) integrin subunit was cloned and sequenced (EMBL accession no. AJ439062). Screening of normal ovine tissues by RT-PCR and immunocytochemistry confirmed that integrin-alphavbeta6 is restricted to sheep epithelial cells. Integrin-alphavbeta6 expression was detected in epithelia of the airways, oral cavity, gastrointestinal tract, kidney, sweat glands, hair follicle sheaths, and the epidermis of pedal coronary band (PB) but not of normal skin. Consistent with FMDV tropism, integrin-alphavbeta6 was detected within the basal layers of the stratified squamous epithelium of the oral mucosa and PB. In addition, integrin-alphavbeta6 appears to be constitutively expressed in the normal airways of both cattle and sheep. The latter finding suggests that ruminant airway epithelium presents a highly accessible target for initiation of infection with FMDV by inhalation.     

湖南鱼类新记录4种

2004年8月～2005年7月,在湖南安化进行鱼类资源调查期间,发现湖南鱼类新记录4种：漓江副沙鳅、盎堂拟鲿、越南鲇和司氏（鱼央）.     

A comprehensive analysis of root morphological changes and nitrogen allocation in maize in response to low nitrogen stress

The plasticity of root architecture is crucial for plants to acclimate to unfavourable environments including low nitrogen (LN) stress. How maize roots coordinate the growth of axile roots and lateral roots (LRs), as well as longitudinal and radial cell behaviours in response to LN stress, remains unclear. Maize plants were cultivated hydroponically under control (4 mm nitrate) and LN (40 μm ) conditions. Temporal and spatial samples were taken to analyse changes in the morphology, anatomical structure and carbon/nitrogen (C/N) ratio in the axile root and LRs. LN stress increased axile root elongation, reduced the number of crown roots and decreased LR density and length. LN stress extended cell elongation zones and increased the mature cell length in the roots. LN stress reduced the cell diameter and total area of vessels and increased the amount of aerenchyma, but the number of cell layers in the crown root cortex was unchanged. The C/N ratio was higher in the axile roots than in the LRs. Maize roots acclimate to LN stress by optimizing the anatomical structure and N allocation. As a result, axile root elongation is favoured to efficiently find available N in the soil.     

大鼠胰岛分离、培养条件的优化及miR-126表达的检测方法比较

目的:优化SD大鼠胰岛细胞的分离、纯化和培养方法与条件,为研究miR-126在Ⅱ型糖尿病中的作用机制提供活性与功能良好的胰岛细胞及miR-126表达的检测方法。方法:水合氯醛腹腔注射麻醉SD大鼠,采用8 mL胶原酶Ⅴ(含DNaseⅠ100 U)逆行注射、原位消化后Hitopaque-1077梯度离心分离纯化SD大鼠胰岛细胞,从培养后的胰岛细胞中提取总RNA,分别用加尾法和茎环法进行miR-126的反转录,实时定量PCR(qPCR)检测miR-126的表达量。结果:用该方法可从每只SD大鼠中分离、纯化得到胰岛细胞372±45个,胰岛细胞纯度90%,胰岛细胞存活率95%;用加尾法和茎环法qPCR检测miR-126的Cp值分别为34.56±2.56和32.47±2.01。结论:胶原酶Ⅴ(含DNaseⅠ100 U)逆行注射、原位消化可有效避免因消化时胶状物质的产生而导致的胰岛细胞分离失败,Hitopque-1077梯度离心分离方法具有操作简单、便捷、成功率高等特点,可得到活性与功能较好的胰岛细胞;与加尾法相比,茎环法能够更灵敏地检测胰岛细胞miR-126的表达量。     

基于叶片尺度观测数据的气孔导度模型评价

气孔导度(g)是控制冠层与大气之间能量和水分交换的重要因素。空气湿度是控制植物叶片气孔导度的一个关键环境因子。在过去的十几年中,普遍得到应用的是Ball-Woodrow-Berry(BWB)模型和Leuning模型中气孔导度与湿度的关系。本研究使用一个诊断变量f(H),基于农田叶片水平的光合-气孔导度观测数据,对BWB模型、Leuning模型以及新发展的power-h模型和power-D模型进行了气孔导度模拟效果的比较和评价。结果表明:BWB模型描述的是g和相对湿度(hs)之间的一种线性关系,当空气较为湿润时,模拟结果存在较大的低估;Leuning模型中反映的是g与饱和水汽压差(Ds)的非线性函数,降低了模拟结果的误差,但仍然不能很好地描述g在较湿状况下的显著升高;相比之下,两个新的模型,即Ds的指数函数和(1-hs)的指数函数形式模型能提高模拟结果的精度。这个研究结果也表明基于Ds的模型模拟效果要好于基于hs的模型。     

Recombinant protein purification from pea

To assess the suitability of transgenic peas as a host for protein production from the perspective of ease of recovery, a strain containing recombinant beta-glucuronidase with poly(histidine) tail (GUSH6) was evaluated for solubility of the target protein in relation to native components (proteins, carbohydrates, and phenolics). Recovery of the recombinant GUSH6 from aqueous extracts by immobilized metal affinity chromatography with coupled Co(2+) yielded a nearly pure product with IDA (enrichment factor (EF) = 260) or NTA (EF = 200) resin. Single-step recoveries were also possible by isoelectric precipitation (EF = 4), polyelectrolyte precipitation (EF = 1.5), and anion-exchange chromatography (EF = 3.1), but enrichment factors were low.     

动物组织中磺胺二甲嘧啶残留ELISA试剂盒研制

采用重氮化法和戊二醛法,将磺胺二甲嘧啶分别与牛血清白蛋白和辣根过氧化物酶偶联制备了免疫原和酶标半抗原,免疫兔获得了特异性抗体,成功建立了相关动物产品中磺胺二甲嘧啶残留ELISA定量检测方法及商品化试剂盒,并对试剂盒的灵敏度、准确度、精密度和稳定性进行了研究。试剂盒检测线性范围为62.5~0.54 ng/mL。在待测样品中各添加500、200、100、50 ng/g SMZ,测试的回收率平均为89.0%~134.8%;试剂盒测定结果与色谱的平均符合率99.8%~126.0%;对比定性测试15份色谱检测为阴性的样品,均未出现假阳性。试剂盒存放在37℃10 d和2~8℃5个月,质量稳定。     

The beta-agonist isoproterenol attenuates EGF-stimulated wound closure in human airway epithelial cells

Asthma is a disease characterized by reversible airway obstruction. An additional hallmark of chronic asthma is altered wound healing that leads to airway remodeling. Although beta-agonists are effective in treating the bronchospasm associated with asthma, their effects on airway wound healing, which are related to airway remodeling, are unknown. It has been demonstrated that beta-agonists can alter the signaling of epidermal growth factor (EGF) receptors, which are important in timely wound healing. Therefore, we hypothesized that the beta-agonist isoproterenol would affect wound healing. Using an in vitro scrape wound assay, we demonstrated that isoproterenol attenuates EGF-stimulated wound healing in 16HBE airway epithelial cell cultures. Through experiments with forskolin and cells overexpressing beta2-adrenergic receptor-yellow fluorescent protein, we show that attenuation is due to the accumulation of cAMP and the involvement of at least one additional pathway. Furthermore, attenuation is not due to a direct effect on the EGF receptor or to an alteration of the ERK/MAPK signaling cascade. Based on these results, we propose that isoproterenol may exert its effects through other MAPK signaling pathways (JNK and/or p38) or through parallel mechanisms. These results also demonstrate a problem of potential therapeutic relevance in which a commonly prescribed medication may alter wound healing and contribute to the remodeling of asthmatic airways.     

The role of chloroplast NAD(P)H dehydrogenase in protection of tobacco plant against heat stress

The environmental temperature is one of the mainfactors affecting plant growth and development. Insummer, plants are frequently influenced by hightemperature. In recent years, global temperature wasremarkably elevated accompanied with the climaticchanges,…     

超声激活血卟啉对S180 肿瘤细胞表面EGFR 表达量的影响

目的：探讨超声激活血卟啉处理S180肿瘤细胞后膜表面EGFR表达量的变化。方法：将腹水瘤细胞随机分为四组,U组和UH组细胞分别于频率1．8MHz、2．0W／cm^2的超声装置中照射3min,并分别在1h3h5h后取材,应用免疫组化方法在光镜下观察EGFR的表达情况。结果：1h、3h取材,U组和UH组平均光密度值明显低于Cr组和H组,UH组最低。而5h取材时,UH组平均光密度值显著下降,其它组基本无变化。结论：提示在高频低强度处理下,随着时间的延长,超声激活HpD对EGFR的抑制作用增加,显示可能是基因调控使EGFR表达下调,从而使肿瘤细胞增殖减慢。