不同强度及时间窗骨骼肌缺血后处理对兔心肌的保护作用

目的:通过比较不同强度及时间窗骨骼肌缺血后处理对兔缺血/再灌注心肌的保护效能,试图寻找最佳强度和时间窗的骨骼肌缺血后处理方案。方法:健康新西兰大白兔42只(雄性)随机分为7组(n=6):①假手术组(Sham)、②缺血对照组(CON)、③标准骨骼肌后处理组(SP)、④延迟6min骨骼肌后处理组(6M-DSP)、⑤延迟1 min骨骼肌后处理组(1M-DSP)、⑥骨骼肌后处理加强组(SSP)、⑦骨骼肌后处理减弱组(WSP)。以开胸结扎冠状动脉左室支固定部位方法制作缺血/再灌注模型,以游离并夹闭双侧腹股沟髂外动脉固定位置方法造成骨骼肌缺血,再灌注末以TTC法确定心肌梗死范围,并分别于心肌缺血前、后及再灌注1 h、2 h,以生化法测定血清肌酸激酶(CK)及乳酸脱氢酶(LDH)水平。结果:和CON组相比,1M-DSP组心肌梗死重量比及面积比分别下降了42.32%及42.68%、SP组分别下降了49.97%及43.78%、SSP组分别下降了48.36%及48.86%,(P均<0.05),但三组之间相比,心梗范围未见明显差异;而6M-DSP、WSP组与CON组相比未见心肌保护作用;肌酸激酶(CK)的水平和梗死范围变化趋势一致。结论:兔在心肌缺血/再灌注之前完成骨骼肌5 min缺血/1 min再灌注1次循环的缺血后处理,可以起到明显的心肌保护作用。     

New bioactive sulfated alkenes from the sea cucumber Apostichopus japonicus

Two new alkene sulfates, (5Z)-dec-5-en-1-yl sulfate (4) and (3E)-dec-3-en-1-yl sulfate (5), together with three known sulfated alkanes, 2,6-dimethylheptyl sulfate (1), octyl sulfate (2), and decyl sulfate (3), were isolated from the sea cucumber Apostichopus japonicus. The structures of the new compounds 4 and 5 were elucidated by spectroscopic analysis, including 1H-, 13C-, and 2D-NMR, ESI-MS, and HR-ESI-MS. Compounds 2 and 3 were isolated from natural sources for the first time. In preliminary bioassays in vitro, compounds 4 and 5 showed antibacterial, antifungal, and cytotoxic activities.     

Optical Absorption Enhancement in Freestanding GaAs Thin Film Nanopyramid Arrays

Although III–V compound semiconductor multi‐junction cells show the highest efficiency among all types of solar cells, their cost is quite high due to expensive substrates, long epitaxial growth and complex balance of system components. To reduce the cost, ultra‐thin films with advanced light management are desired. Here effective light trapping in freestanding thin film nanopyramid arrays is demonstrated and multiple‐times light path enhancement is realized, where only 160 nm thick GaAs with nanopyramid structures is equivalent to a 1 μm thick planar film. The GaAs nanopyramids are fabricated using a combination of nanosphere lithography, nanopyramid metal organic chemical vapor deposition (MOCVD) growth, and gas‐phase substrate removal processes. Excellent optical absorption is demonstrated over a broad range of wavelengths, at various incident angles and at large‐curvature bending. Compared to an equally thick planar control film, the overall number of photons absorbed is increased by about 100% at various incident angles due to significant antireflection and light trapping effects. By implementing these nanopyramid structures, III–V material usage and deposition time can be significantly reduced to produce high‐efficiency, low‐cost thin film III–V solar cells.     

The effects of NMDA subunit composition on calcium influx and spike timing-dependent plasticity in striatal medium spiny neurons

Calcium through NMDA receptors (NMDARs) is necessary for the long-term potentiation (LTP) of synaptic strength; however, NMDARs differ in several properties that can influence the amount of calcium influx into the spine. These properties, such as sensitivity to magnesium block and conductance decay kinetics, change the receptor's response to spike timing dependent plasticity (STDP) protocols, and thereby shape synaptic integration and information processing. This study investigates the role of GluN2 subunit differences on spine calcium concentration during several STDP protocols in a model of a striatal medium spiny projection neuron (MSPN). The multi-compartment, multi-channel model exhibits firing frequency, spike width, and latency to first spike similar to current clamp data from mouse dorsal striatum MSPN. We find that NMDAR-mediated calcium is dependent on GluN2 subunit type, action potential timing, duration of somatic depolarization, and number of action potentials. Furthermore, the model demonstrates that in MSPNs, GluN2A and GluN2B control which STDP intervals allow for substantial calcium elevation in spines. The model predicts that blocking GluN2B subunits would modulate the range of intervals that cause long term potentiation. We confirmed this prediction experimentally, demonstrating that blocking GluN2B in the striatum, narrows the range of STDP intervals that cause long term potentiation. This ability of the GluN2 subunit to modulate the shape of the STDP curve could underlie the role that GluN2 subunits play in learning and development.     

Optimization of genetic transformation system of potato and introduction of maize starch branching enzyme gene SBEⅡb into potatoFAN

以马铃薯脱毒试管苗茎段为转化受体材料,建立并优化了农杆菌介导的马铃薯遗传转化体系.通过农杆菌介导法将玉米淀粉分支酶基因(Starch branching enzyme b,SBEⅡb)的过表达载体转化马铃薯,接种762个茎段,共获得35株抗性植株.经PCR检测获得了4株转基因阳性植株;对转基因植株进一步进行GUS活性组织化学染色,发现转基因植株的茎段与试管薯均被染上蓝色,表明外源SBEⅡb基因已整合到马铃薯基因组,且正常表达.     

生长素与植物逆境胁迫关系的研究进展

生长素(IAA)是一种重要的植物激素,与植物的逆境胁迫反应关系密切。综述近年来国内外对生长素与植物逆境胁迫关系研究的一些最新进展,重点分析生长素和生长素响应基因及其相关转录因子在植物响应盐害、干旱、低温等胁迫中的反应。     

叶绿体基因工程研究进展

叶绿体是植物细胞和真核藻类执行光合作用的重要细胞器,在叶绿体中表达外源基因比在细胞核中表达具有一些独特优势。叶绿体基因工程涉及叶绿体的基因组特征、转化系统的优点、转化过程及方法等方面,叶绿体基因工程在提高植物光合效率、改良植物特性、生产生物药物及改善植物代谢途径等方面已得到应用。尽管叶绿体基因工程还存在同质化难度高、标记基因转化效率较低、宿主种类偏少等问题,但作为外源基因在高等植物中表达的良好平台其仍然具有广阔的发展和应用前景。     

荚蒾属植物花期物候及生长对引种地年际气候波动的响应

专属引种植物的物候及生长研究能够掌握特定物候相在专属水平上的阈值,并为评估引种专属的适应潜力提供参考。通过对中国科学院植物研究所北京植物园内引种多年的9种荚蒾（Viburnum）的花期及2种荚蒾的生长动态进行观测,分析讨论了花期对冬春两季异常低温的响应及营养与生殖生长的关联机制。结果表明：2009–2010年冬春异常低温后,荚蒾始花期的整体延迟是由春季环境热量供应不及时所致,种间延迟程度的差异则与原产地的气候有紧密联系：分布于寒温带地区的欧洲绣球（V.opulus）和修枝荚蒾（V.burejaeticum）延迟天数最少（分别为10和12天）,分布于我国亚热带的琼花（V.macrocephalum）和桦叶荚蒾（V.betulifolium）延迟天数最多（分别为21和26天）。荚蒾花前有效积温介于39–368°C之间。经历异常低温后,花前有效积温呈上升和下降两种格局,与物种冷量和热量的内在需求有关。荚蒾属植物的生殖与营养生长呈现两种关联方式,早花种类开花座果伴随着营养生长的竞争,晚花种类花后即出现营养生长的支持,对果实发育的保障性较强。     

黄粉虫胰蛋白酶样酶基因TMTLSP全长cDNA的克隆和序列分析

以黄粉虫(Tenebrio molitor)幼虫全RNA逆转录得到的cDNA为模板,参照地鳖（Eupolyphaga sinensis）纤溶酶（fibrinolytic enzyme）简并引物,进行温度梯度PCR．以得到的扩增产物为基础,采用RACE得到基因全长cDNA,命名为黄粉虫胰蛋白酶样丝氨酸蛋白酶(Tenebrio molitor trypsin-like serine protease,TMTLSP)．TMTLSP全长869 bp(GenBank No. JN662461),开放阅读框为777 bp,编码258个氨基酸,并具有蛋白酶样特有的起始位点、活性中心预计底物结合位点．经过比对分析,该基因编码的氨基酸序列与赤拟谷盗、谷蠹、光亮扁角水虻、美洲大蠊等多种昆虫的胰蛋白酶或丝氨酸蛋白酶有较高的相似性．本研究将为胰蛋白酶样丝氨酸蛋白酶的提取及研究提供更为广泛的材料及研究依据．