应用激光扫描共聚焦显微镜FRAP技术研究兔早期胚胎发育中细胞间隙连接介导通讯

本研究应用激光扫描共聚焦显微镜的光漂白恢复技术(FRAP)分析兔早期胚胎卵裂球之间通过间隙连接介导的细胞通讯(GJIC)。研究结果发现,用强激光分别将4-细胞期胚胎、异裂胚胎和8-细胞期胚胎的一个卵裂球荧光光漂白后,经过15分钟的荧光恢复,4-细胞期胚胎的光漂白恢复率为17.8％,异裂胚胎的光漂白恢复率为23.7％,二者之间没有明显的差异;8-细胞期胚胎的光漂白恢复率为78.2％,与前二者之间存在明显的差异。推测兔早期胚胎卵裂球细胞间隙连接建立的时间在8-细胞阶段,胚胎卵裂球间隙连接通讯可能是兔胚胎正常发育的重要条件。     

激光辐照洋葱种子的生物学效应初探

采用Ｈｅ－Ｎｅ激光和ＣＯ２激光辐照洋葱两个品种的湿种子,采用随机区组设计,重复３次,利用生物统计学的方法,从个体水平上初步考查诱变Ｌ１代的生物学效应。结果表明：在出苗率、苗高、叶数、须根长、须根数、苗重、须根重等性状表现出不同处理所引起的生物学效应差异,激光种类不同,引起须根长的变异达到５％的显著差异,激光剂量不同引起须根数变异显著,苗高和苗重的变异达到极显著。     

激光扫描共聚焦显微镜系统及其在细胞生物学中的应用

激光扫描共聚焦显微镜是近十年发展起来的医学图象分析仪器,现已广泛应用于荧光定量测量、共焦图象分析、三维图象重建、活细胞动力学参数监测和胞间通讯研究等方面。其性能为普通光学显微镜质的飞跃,是电子显微镜的一个补充。本文以美国Ｍｅｒｉｄｉａｎ公司的ＡＣＡＳＵＬＴＩＭＡ３１２为例简要介绍了激光扫描共聚焦显微镜系统的结构、功能和生物学应用前景。     

不同微生物的单光束激光陷阱操纵

本文报导了分别采用Ｈｅ－Ｎｅ和Ａｒ＾＋激光器与光不显微镜构成的单光束激光陷阱操纵酵母菌、青霉等不同微生物的实验观察结果,讨论了操纵条件。研究表明：用单光束高会聚激光产生的梯度力操纵微生物体,其有效作用力的大小不仅与激光功率、波长、束腰半径和光束会聚角有关,还与微生物的大小、吸收系数、菌龄及培养方法等因素有关。     

CT增强对比剂的不同浓度和流速对肾脏增强图像质量的影响

目的：探讨128排螺旋CT扫描增强对比剂的不同浓度和流速对肾脏增强图像质量的影响。方法：回顾性分析2011年7月~2013年5月间于我院影像科行腹部增强CT扫描检查的患者136例,对采用不同浓度（300 mgI/mL、350 mgI/mL）和不同流速（3 mL/s、5 mL/s）的图像质量,选取选取左肾动脉开口处腹主动脉（D）、左/右肾脏动脉（E）、左/右肾脏静脉（F）、左/右肾皮质（G）、左/右肾实质（H）作为感兴区进行分析,评估碘海醇浓度及流速增强剂对图像质量的影响。结果：不同浓度相同流速增强剂对图像质量的影响比较：左肾动脉开口处腹主动脉、肾脏动脉、肾脏静脉血管显影质量比较差异无统计学意义,P〉0.05;肾皮质、肾实质差异有统计学意义,P〈0.05;相同浓度不同流速增强剂对图像质量的影响差异各部位均有统计学意义,均P〈0.05。结论：较高碘海醇使用浓度和较快的注射流速对肾脏血流显影有帮助,因此,在安全剂量范围内,适当增加碘海醇使用浓度及增加对比剂的注射速度会提高肾脏增强扫描的图像质量。     

Determination of key residues in tospoviral NSm required for Sw-5b recognition,their potential ability to overcome resistance,and the effective resistance provided by improved Sw-5b mutants

Sw-5b is an effective resistance gene used widely in tomato to control tomato spotted wilt virus (TSWV), which causes severe losses in crops worldwide. Sw-5b confers resistance by recognizing a 21-amino-acid peptide region of the viral movement protein NSm (NSm21, amino acids 115–135). However, C118Y or T120N mutation within this peptide region of NSm has given rise to field resistance-breaking (RB) TSWV isolates. To investigate the potential ability of TSWV to break Sw-5b-mediated resistance, we mutagenized each amino acid on NSm21 and determined which amino acid mutations would evade Sw-5b recognition. Among all alanine-scan mutants, NSm^P119A, NSm^W121A, NSm^D122A, NSm^R124A, and NSm^Q126A failed to induce a hypersensitive response (HR) when coexpressed with Sw-5b in Nicotiana benthamiana leaves. TSWV with the NSm^P119A, NSm^W121A, or NSm^Q126A mutation was defective in viral cell-to-cell movement and systemic infection, while TSWV carrying the NSm^D122A or NSm^R124A mutation was not only able to infect wild-type N. benthamiana plants systemically but also able to break Sw-5b-mediated resistance and establish systemic infection on Sw-5b-transgenic N. benthamiana plants. Two improved mutants, Sw-5b^{L33P/K319E/R927A} and Sw-5b^{L33P/K319E/R927Q}, which we recently engineered and which provide effective resistance against field RB isolates carrying NSm^C118Y or NSm^T120N mutations, recognized all NSm21 alanine-substitution mutants and conferred effective resistance against new experimental RB TSWV with the NSm^D122A or NSm^R124A mutation. Collectively, we determined the key residues of NSm for Sw-5b recognition, investigated their potential RB ability, and demonstrated that the improved Sw-5b mutants could provide effective resistance to both field and potential RB TSWV isolates.     

Analysis of major elements in pigmented melanocytic chicken skin using laser‐induced breakdown spectroscopy

The concentration difference of major elements in melanocytic skin with respect to pigmentation level is analysed by laser‐induced breakdown spectroscopy (LIBS) to investigate the applicability of LIBS as an in situ feedback tool for selective and complete laser removal of melanocytic skin tissue like nevus. The skin of black silkie chicken which had a characteristic darkly pigmented perifollicular skin surrounded by lightly pigmented extrafollicular skin was used as the sample. The results showed higher LIBS signal intensities of Ca²⁺ and Mg²⁺ but lower intensities of Na⁺, Cl^– and K⁺ in the perifollicular skin than in the extrafollicular skin, which demonstrated the feasibility to use LIBS as a reliable method to distinguish skin tissues with difference in pigmentation level.

Plasma emission of biochemical elements generated with a laser irradiation on melanocytic skin lesion.     

Navigated laser capture microdissection as an alternative to direct histological staining for proteomic analysis of brain samples

Proteomic analysis of the brain is complicated by the need to obtain cells from specific anatomical regions, or nuclei. Laser capture microdissection (LCM) is a technique that is precise enough to dissect single cells within a tissue section, and thus could be useful for isolating specific brain nuclei for analysis. However, we and others have previously demonstrated that histological staining protocols used to guide LCM have detrimental effects on protein separation by two-dimensional electrophoresis (2-DE). Here we describe a new LCM method called navigated LCM. This microdissection method uses fixed but unstained tissue as starting material and thus enables us to avoid artifacts induced by tissue staining. By comparing 2-DE results obtained from fixed, unstained LCM brain tissue samples to those obtained from manually dissected samples, we demonstrated that this microdissection process gave similar protein recovery rates and similar resolution of protein spots on 2-DE gels. Moreover, matrix-assisted laser desorption/ionization-time of flight mass spectrometry analysis of selected spots from gels derived from control and fixed, LCM samples revealed that the fixation-LCM process had no effect on protein identification. Navigated LCM of tissue sections is therefore a practical and powerful method for performing proteomic studies in specifically defined brain regions.     

The population genomic signature of environmental association and gene flow in an ecologically divergent tree species Metrosideros polymorpha (Myrtaceae)

Genomewide markers enable us to study genetic differentiation within a species and the factors underlying it at a much higher resolution than before, which advances our understanding of adaptation in organisms. We investigated genomic divergence in Metrosideros polymorpha, a woody species that occupies a wide range of ecological habitats across the Hawaiian Islands and shows remarkable phenotypic variation. Using 1659 single nucleotide polymorphism (SNP) markers annotated with the genome assembly, we examined the population genetic structure and demographic history of nine populations across five elevations and two ages of substrates on Mauna Loa, the island of Hawaii. The nine populations were differentiated into two genetic clusters distributed on the lower and higher elevations and were largely admixed on the middle elevation. Demographic modelling revealed that the two genetic clusters have been maintained in the face of gene flow, and the effective population size of the high‐altitude cluster was much smaller. A F_ST‐based outlier search among the 1659 SNPs revealed that 34 SNPs (2.05%) were likely to be under divergent selection and the allele frequencies of 21 of them were associated with environmental changes along elevations, such as temperature and precipitation. This study shows a genomic mosaic of M. polymorpha, in which contrasting divergence patterns were found. While most genomic polymorphisms were shared among populations, a small fraction of the genome was significantly differentiated between populations in diverse environments and could be responsible for the dramatic adaptation to a wide range of environments.     

He-Ne激光和增强UV-B辐射对拟南芥叶片微管蛋白的影响

采用He-Ne激光生物辐照仪（632.8 nm,5 mW·mm-2）、UV-B（15.55 KJ·m-2·d-1）及二者复合处理拟南芥幼苗后提取微管蛋白,考马斯亮蓝法测含量和SDS-PAGE凝胶电泳进行初步分析,并用免疫印迹鉴定微管蛋白.结果表明：单独UV-B使微管蛋白解聚,He-Ne激光和UV-B复合处理后,微管蛋白解聚程度减小,单独He-Ne激光处理促进微管聚合.因此认为He-Ne激光在一定程度上缓解了UV-B对微管蛋白的解聚作用.