神经生长因子介导的促神经生长化合物筛选系统的建立

为了合理评价化合物的促神经再生活性.用溴化四唑蓝(MTT)、分化计数、图象处理等方法，借助FK506、GPI1046阳性化合物，建立了一个基于PC12细胞存活和分化的化合物筛选系统.结果表明，无论在细胞存活实验还是在分化实验中，FK506、GPI1046都可以明显增强神经生长因子(NGF)的效应，即有促神经再生的作用.也就是说，这一系统将有助于从组合化学方法合成的化合物文库中，筛选出具有促神经再生活性的化合物.     

The use of image analysis to monitor the germination of seeds of broccoli (Brassica oleracea) and radish (Raphanus sativus)

To study broccoli and radish seed germination under different temperature regimes the germination test has been used to assess final germination percentage, start and rate. This method has been integrated with a computer‐aided image analysis test which is more accurate in monitoring the extent of imbibition phases through the assessment of seed area increase and timing of radicle emergence detected on single seeds. In addition, seed area increase has been used also to establish a close relationship with radicle elongation rate in the time range when ‘visible germination’ is scored by a classical germination test. The results suggest that this image analysis parameter may be considered as a reliable seed imbibition marker to integrate the germination parameters obtained by a germination test.     

Using vegetation indices derived from conventional digital cameras as selection criteria for wheat breeding in water-limited environments

The ability to assess green biomass is of particular interest in a number of wheat breeding environments. However, the measurement of this and similar traits is either tedious and time-consuming or requires the use of expensive, sophisticated equipment, such as field-based spectroradiometers to measure vegetation indices (VIs). Here, conventional digital cameras are proposed as affordable and easy-to-use tools for gathering field data in wheat breeding programmes. Using appropriate software, a large set of images can be automatically processed to calculate a number of VIs, based on the performance of simple colour operations on each picture. The purpose of this study was to identify a set of picture-derived vegetation indices (picVIs) and to evaluate their performance in durum wheat trials growing under rainfed and supplementary irrigation conditions. Here, zenithal pictures of each plot were obtained roughly 2 weeks after anthesis, and the picVIs that were calculated were compared with the normalised difference vegetation index (NDVI), an index derived from spectroradiometrical measurements, and with the grain yield (GY) from the same plots. The picVIs that performed best were the Hue, CIE-Lab a* and CIE-Luv u* components of the average colour of each picture, the relative green area (GA) and the 'greener area', similar to GA but excluding the more yellowish-green pixels. Our results showed a high correlation between all these picVIs and the NDVI. Moreover, in rainfed conditions, each picVI provided an estimation of GY similar to or slightly better than that provided by the NDVI. However, in irrigated conditions during anthesis, neither these picVIs nor the NDVI provided a good estimation of GY, apparently because of the saturation of the VI response in conditions of complete soil cover and high plant density.     

Ultraviolet inactivation and excision-repair in Bacillus subtilis. II. Differential inactivation and differential repair of transforming markers

Ultraviolet inactivation of transforming Bacillus subtilis markers was studied with the aid of an eightfold auxotrophic recipient and its excision-repair-deficient derivative. The results allow the following conclusions. (i) Wild-type B. subtilis cells are able to repair approx. 80% of the UV-induced lesions causing inactivation of transforming activity in UV-sensitive recipients; (ii) Saturating amounts of donor DNA increase the apparent marker sensitivities. This phenomenon is most pronounced in transformation of UV-sensitive recipients; (iii) various markers are inactivated to different degrees, both when assayed on the wild-type as well as on the UV-sensitive strain; (iv) Various markers are repaired to different degrees in the wild-type recipient.     

The α-galactosidase from Escherichia coli K12

Growth of Escherichia coli on melibiose requires the induced synthesis of α-galactoside permease and α-galactosidase. Hydrolysis of the chromogenic substrate p-nitrophenyl-σ-galactoside by whole bacteria is dependent on intact oxidative metabolism. The α-galactosidase from E. coli was isolated for the first time as a soluble enzyme. In cell-free extracts p-nitrophenyl-α-galactoside hydrolisis was observed only at high protein concentrations and the activity decreased exponentially with the square of the dilution. The reason for this behaviour was shown to be that, unlike other known α-galactosidases, the enzyme of E. coli requires NAD. For optimal activity the enzyme also requires Mn²⁺, a high concentration of 2-mercaptoethanol, and a pH of 8.1. The approximate molecular weight of the active from of α-galactosidase as determined by sedimentation in a sucrose gradient is 200 000. Due to the instability of the enzyme, its purification has not been achieved.     

Using unmanned aerial vehicle (UAV) surveys and image analysis in the study of large surface‐associated marine species: a case study on reef sharks Carcharhinus melanopterus shoaling behaviour

A novel image analysis‐based technique applied to unmanned aerial vehicle (UAV) survey data is described to detect and locate individual free‐ranging sharks within aggregations. The method allows rapid collection of data and quantification of fine‐scale swimming and collective patterns of sharks. We demonstrate the usefulness of this technique in a small‐scale case study exploring the shoaling tendencies of blacktip reef sharks Carcharhinus melanopterus in a large lagoon within Moorea, French Polynesia. Using our approach, we found that C. melanopterus displayed increased alignment with shoal companions when distributed over a sandflat where they are regularly fed for ecotourism purposes as compared with when they shoaled in a deeper adjacent channel. Our case study highlights the potential of a relatively low‐cost method that combines UAV survey data and image analysis to detect differences in shoaling patterns of free‐ranging sharks in shallow habitats. This approach offers an alternative to current techniques commonly used in controlled settings that require time‐consuming post‐processing effort.     

The impact of mechanical compression on cortical microtubules in Arabidopsis: a quantitative pipeline

Exogenous mechanical perturbations on living tissues are commonly used to investigate whether cell effectors can respond to mechanical cues. However, in most of these experiments, the applied mechanical stress and/or the biological response are described only qualitatively. We developed a quantitative pipeline based on microindentation and image analysis to investigate the impact of a controlled and prolonged compression on microtubule behaviour in the Arabidopsis shoot apical meristem, using microtubule fluorescent marker lines. We found that a compressive stress, in the order of magnitude of turgor pressure, induced apparent microtubule bundling. Importantly, that response could be reversed several hours after the release of compression. Next, we tested the contribution of microtubule severing to compression‐induced bundling: microtubule bundling seemed less pronounced in the katanin mutant, in which microtubule severing is dramatically reduced. Conversely, some microtubule bundles could still be observed 16 h after the release of compression in the spiral2 mutant, in which severing rate is instead increased. To quantify the impact of mechanical stress on anisotropy and orientation of microtubule arrays, we used the nematic tensor based FibrilTool ImageJ/Fiji plugin. To assess the degree of apparent bundling of the network, we developed several methods, some of which were borrowed from geostatistics. The final microtubule bundling response could notably be related to tissue growth velocity that was recorded by the indenter during compression. Because both input and output are quantified, this pipeline is an initial step towards correlating more precisely the cytoskeleton response to mechanical stress in living tissues.     

椎体后凸成形术治疗老年骨质疏松脊柱压缩骨折的临床分析

目的分析老年骨质疏松脊柱压缩骨折行椎体后凸成形术的治疗方法及临床效果,为临床提供依据。方法回顾性分析我院2014年10月~2015年10月收治的老年骨质疏松脊柱压缩骨折患者40例的临床资料,全部患者均为椎体后壁完整疼痛性骨质疏松脊柱压缩骨折,均接受椎体后凸成形术治疗,经双侧椎弓根、椎弓根旁置入可扩张球囊,将骨折塌陷椎体进行复位,采取骨水泥填充球囊扩张产生的椎体内空腔,术后观察患者症状改善和骨折复位情况。结果 40例患者手术均顺利完成,术后48h内患者疼痛显著缓解,骨折椎体前缘以及中部高度丢失,从手术前的(12.5±2.2)mm、(9.1±1.3)mm减少到手术后的(4.6±1.4)mm、(3.3±1.0)mm;后凸畸形Cobb角从手术前的(22.2±5.1)°矫正到手术后的(9.1±4.6)°,其中1例患者术后出现少量骨水泥渗漏,1例患者手术过程中一侧穿刺管中出现脑脊液,即停止该侧手术。结论老年骨质疏松脊柱压缩骨折行椎体后凸成形术治疗效果显著,可以快速缓解患者的疼痛,使患者脊柱序列得到恢复,值得临床推广使用。