视网膜神经节细胞感受野的一种新模型 I.含大周边的感受野模型

感受野是视觉系统信息处理的基本结构和功能单元。Ｘ、Ｙ细胞是两类主要的视网膜神经节细胞。生理实验发现,在经典感受野之外还存在一个大范围的在周边去抑制区。文中采用周边去抑制区对经典外周的去抑制非线性使用方式,建立一个二维的与实验结果联系紧密的Ｘ、Ｙ细胞统一的复合感受野模型。该模型不仅能模拟Ｘ细胞的ｎｕｌｌ－ｔｅｓｔ反应和Ｙ细胞的ｏｎ－ｏｆｆ反应,还模拟了Ｙ细胞在低空频刺激时的信频反应、圆面积空间的倍频     

应用基于内源信号的光学成像技术的视觉脑研究现状

基于脑内源信号的光学成像技术是近来国际上出现的一种脑功能成像方法。该技术既无毒,又具有较高的空间分辨率,因而被迅速应用于动物的视觉、听觉、体感皮层功能构筑的研究中。本文综述了这种光学脑功能成像在视觉脑研究方面所取得的重要进展,并分析了该方法与其他脑成像技术、微电极单细胞技术的关系。报道了国内自行研制第、套脑功能光学成像系统的研究工作,该系统已在猫初级视觉皮层不同深度获得了清晰的方位功能图,并已经和     

色疣节梗孢属一中国新记录种

【目的】调查我国植物病原真菌资源与多样性。【方法】采用经典真菌形态分类方法并结合序列分析结果对研究样品进行鉴定。【结果】从浙江省绍兴市平水镇的林下枯叶上分离到尖色疣节梗孢,对尖色疣节梗孢的形态特征进行了详细的观察和描述,并对其ITS rDNA序列进行分析。【结论】金缕梅叶斑病的尖色疣节梗孢病原菌在我国是首次发现,为我国真菌新记录种。     

基于生态系统服务供求评价的空间分异特征与生态格局划分——以长三角城市群为例

生态系统服务供给与需求能力存在显著的空间异质性与空间失衡,对区域经济发展与环境保护产生巨大影响。以长三角城市群区县为研究单元,分别核算其生态系统服务供给与需求值,引入梯度分析,分析生态系统服务供给与需求的空间特征,并基于供求分析提出长三角城市群生态格局分区方案,且针对性地提出相应片区的发展策略,为长三角城市群土地利用规划、区域协调发展提供科学依据。研究结果表明:(1)长三角城市群生态系统服务供给能力与土地利用类型密切相关,呈现从北到南逐渐升高趋势;(2)长三角城市群生态系统服务需求能力与社会经济发展联系紧密,在长江入海口附近形成生态系统服务需求高值区,然后向外围递减;(3)沪宁杭庐发展梯度带上,生态系统服务供需大致呈现负相关趋势;(4)基于生态系统服务供需关系构建,得到长三角城市群生态格局四大分区:生态保育区(高供给-高需求),生态修复区(低供给-高需求),生态重塑区(低供给-低需求),生态开发区(高供给-低需求)。     

舟山海域大中型浮游动物群落时空变化及受控要素

为更好地保护舟山海域的渔业资源和生态环境,了解舟山海域浮游动物组成的时空变化,于2014年到2017年对舟山海域33个站位开展4个季节的生态综合调查,结果表明:4个航次共鉴定出浮游动物成体88种和浮游幼体19类,优势种共12种,浮游动物的优势种更替和群落特征季节变化明显,春夏、夏秋、秋冬、冬春相邻季节优势种更替率分别为75%、80%、100%和60%;平均生物量为夏季(176.34 mg/m³)>春季(120.20 mg/m³)和秋季(86.28 mg/m³)>冬季(7.21 mg/m³);平均丰度为夏季(143.97个/m³)>春季(86.30个/m³)>秋季(21.38个/m³)和冬季(26.86个/m³);平均多样性指数:夏季(3.03)>秋季(2.82)>春季(2.05)>冬季(1.71)。舟山海域浮游动物群落具有明显的季节和区域差异,温度、盐度、Chl a和营养盐是影响舟山浮游动物群落时空变化的主要环境因素,其中春季浮游动物群落空间分布主要受盐度的影响,夏季主要受温度、盐度和Chl a的影响,秋季主要受Chl a的影响,冬季主要受悬浮物和溶解氧的影响,而营养盐对每个季节的浮游动物群落分布都有一定的影响。     

视觉剥夺猫外膝体神经元最优方位的分布特性

记录和测定了视觉剥夺猫（ｄａｒｋ－ｒｅａｒｅｄｃａｔｓ）外膝体３４４个细胞的方位调谐等感受野特性,多数细胞（８２％）具有方位敏感性（Ｂｉａｓ＞０．１）。最优方位的分布与正常猫类似,偏向于水平方位,但分布特性强于正常猫。与正常猫类似,视觉剥夺猫外膝体细胞的最优方位与该细胞感受野在视网膜上的位置有关,偏向平行于视网膜中心区与感受野中心的连线（向心线）;外膝体内位置相邻近的细胞具有相近的最优方位,亦呈现初步有序排列。结果表明：外膝体细胞最优方位的分布特性与后天视觉经验无关而可能来源于遗传因素。     

Microarray analysis reveals a potential role of LncRNAs expression in cardiac cell proliferation

Background

Long non-coding RNAs (LncRNAs) have been identified to play important roles in epigenetic processes that underpin organogenesis. However, the role of LncRNAs in the regulation of transition from fetal to adult life of human heart has not been evaluated.

Methods

Immunofiuorescent staining was used to determine the extent of cardiac cell proliferation. Human LncRNA microarrays were applied to define gene expression signatures of the fetal (13–17 weeks of gestation, n?=?4) and adult hearts (30–40 years old, n?=?4). Pathway analysis was performed to predict the function of differentially expressed mRNAs (DEM). DEM related to cell proliferation were selected to construct a lncRNA-mRNA co-expression network. Eight lncRNAs were confirmed by quantificational real-time polymerase chain reaction (n?=?6).

Results

Cardiac cell proliferation was significant in the fetal heart. Two thousand six hundred six lncRNAs and 3079 mRNAs were found to be differentially expressed. Cell cycle was the most enriched pathway in down-regulated genes in the adult heart. Eight lncRNAs (RP11-119 F7.5, AX747860, HBBP1, LINC00304, TPTE2P6, AC034193.5, XLOC_006934 and AL833346) were predicted to play a central role in cardiac cell proliferation.

Conclusions

We discovered a profile of lncRNAs differentially expressed between the human fetal and adult heart. Several meaningful lncRNAs involved in cardiac cell proliferation were disclosed.

     

植物的质体转基因及其应用

文章就植物质体转基因的发展历程、技术原理、最新的研究进展和技术突破进行介绍,并对这一技术的应用前景作了展望。     

Comparative proteomic analysis provides new insights into mulberry dwarf responses in mulberry (Morus alba L.)

Mulberry dwarf (MD) is a serious infectious disease of mulberry caused by phytoplasma. Infection with MD phytoplasma results in stress phenotypes of yellowing, phyllody, stunting, proliferation, and witches' broom. Physiological and biochemical analysis has shown that infection with MD phytoplasma causes an increase in soluble carbohydrate and starch content, and a decrease in the net photosynthesis rate, carboxylation efficiency, and pigment content of leaves. Furthermore, damage to the chloroplast ultrastructure was detected in infected leaves. To better understand the pathogen‐stress response of mulberry (Morus alba L.) to MD phytoplasma, we conducted a comparative proteomic analysis using 2‐DE of infected and healthy leaves. Among 500 protein spots that were reproducibly detected, 20 were down‐regulated and 17 were up‐regulated. MS identified 16 differentially expressed proteins. The photosynthetic proteins rubisco large subunit, rubisco activase, and sedoheptulose‐1,7‐bisphosphatase showed enhanced degradation in infected leaves. Based these results, a model for the occurrence mechanism of MD is proposed. In conclusion, this study provides new insights into the mulberry response to MD phytoplasma infection.