碱性成纤维细胞生长因子对牙周膜细胞内核心蛋白多糖基因表达的影响

利用外源性碱性成纤维细胞生长因子(Basic Fibroblast Growth Factor,bFGF)刺激体外培养的人正常牙周膜细胞.采用逆转录-聚合酶链式反应(RT-PCR)检测细胞内decorin的基因表达的变化,研究bFGF对体外培养的人牙周膜细胞内核心蛋白多糖(decorin)的作用,进一步探讨bFGF抑制Ⅰ型胶原的作用机制.发现bFGF刺激牙周膜细胞后能促进牙周膜细胞的增殖,bFGF抑制decorin的合成是bFGF促进牙周膜细胞增殖的重要调节因素之一.     

切断鸣管神经支对红嘴相思鸟鸣声的影响

该研究以红嘴相思鸟(Leiothrix lutea)为材料,分析对其鸣管神经支(NXIIts)进行断单侧和断双侧处理后的鸣声声学变化,探讨鸣管神经支配特性。结果表明,断单侧NXIIts后红嘴相思鸟均可发出常见叫声,但鸣声音节间隔拉长,音节时程缩短,调频指数下降,且断左侧NXIIts的作用效果明显大于断右侧NXIIts。即NXIIts支配具单侧性,且呈左侧优势,此外,左侧NXIIts还具有产生音节高频成分和谐波的作用。断双侧NXIIts后,红嘴相思鸟鸣声音调唯一,响度大幅下降,音节脉冲数增加。     

雷公藤红素抑制Cd2+诱导的神经毒性北大核心CSCD

镉(cadmium,Cd)是环境中常见的一种重金属,Cd^(2+)可以通过穿透血脑屏障,产生神经毒性,从而诱发各种神经退行性疾病,雷公藤红素是雷公藤的一种有效成分,具有抗癌、抗炎等一系列药理作用,本文探究雷公藤红素对Cd^(2+)诱导的相应神经毒性的影响作用。通过细胞增殖实验、细胞膜完整性实验、细胞形态实验探索了Cd^(2+)对小胶质细胞HMC3活力的影响;通过一氧化氮(NO)检测实验、脂质过氧化(malondialdehyde,MDA)检测实验、蛋白免疫印迹实验分析了Cd^(2+)的神经毒性以及雷公藤红素对Cd^(2+)诱导的相应神经毒性的影响。结果表明:与对照组相比,当Cd^(2+)浓度达到40μmol/L时,对HMC3细胞增殖抑制率为(57.17±8.23)%(P<0.01,n=5),继续增大Cd^(2+)浓度,细胞活性将进一步降低;当Cd^(2+)浓度达到40μmol/L以上时,HMC3的细胞膜明显受到破坏,并且破坏作用与浓度呈剂量依赖性关系;随着Cd^(2+)浓度的增加,细胞形态开始变化,贴壁效果变差。Cd^(2+)使HMC3细胞释放的NO量显著增加,而雷公藤红素能够有效地抑制Cd^(2+)诱导的HMC3细胞NO的释放;Cd^(2+)使HMC3细胞脂质过氧化水平显著增加,加入10^(-7) mol/L雷公藤红素后,MDA的释放量显著减少;Cd^(2+)会使p-PI3K蛋白含量增加,而加入了雷公藤红素(10^(-7)、10^(-6) mol/L)后,p-PI3K蛋白和p-AKT蛋白的激活均被抑制,从而抑制了细胞凋亡。综上所述,雷公藤红素能够抑制Cd^(2+)诱导的小胶质细胞毒性,从而起到神经保护作用。     

菌株DN2对烟草薄片制备液中烟碱的降解

使用O.intermedium DN2降解烟草薄片制备液中的烟碱。研究了各种工艺参数对烟碱降解的影响,单因素考察结果表明烟草薄片制备液中烟碱降解的最适条件是:添加0.1%的酵母膏,使用氨水将pH调节到7.0,接种15%种子液,培养温度30oC。在上述条件下,采用30L发酵罐对烟草薄片制备液进行3个批次的半连续发酵,烟碱的平均降解速率为140.55mg/L/h,高于其他烟碱降解菌株。该结果表明菌株DN2可以用来降低烟草薄片中的烟碱含量。     

Integrated soil and plant phosphorus management for crop and environment in China. A review

In semi-arid grassland ecosystems, soil biogeochemical processes are controlled by seasonal and inter-annual rainfall variation and temperature, which may override the long-term impact of grazers on N availability and N dynamics. In a three-year (2004?C2006) case study of an Inner Mongolian grassland, we analysed time-integrated (ion-exchange resins) and instantaneous (soil mineral N extractions) inorganic N availability at three sites of varying grazing intensities and combined these data with information on soil water content (SWC), aboveground net primary productivity (ANPP) and plant N uptake. Additionally, the effects of rainfall and grazing on N-form availability (NO ₃ ^? -N, NH ₄ ⁺ -N) were considered. Grazing had less impact on N availability compared to seasonal and annual rainfall distribution. One of the three study years (2004) showed a grazing effect with higher resin-N availability at the ungrazed site compared to the heavily grazed site. Inorganic N availability was low in the driest year (2005) and highest in a year of average rainfall amount and favourable distribution (2004). In general, we found a positive relationship between inorganic N availability and both plant productivity and plant N uptake. Rainfall also controlled the plant available NO ₃ ^? -N and NH ₄ ⁺ -N pools; NH ₄ ⁺ -N dominated the available inorganic N-form in times of low SWC, while the available NO ₃ ^? -N increased with SWC. We observed N availability and plant productivity in a temporal synchronized pattern. Increased rainfall variability and land-use practices affecting SWC will likely alter N availability dynamics (and the relation of N-forms) and, therefore, important processes of semi-arid natural grassland carbon and N cycling.     

Genome-wide comparative analysis of DNAJ genes and their co-expression patterns with HSP70s in aestivation of the sea cucumber Apostichopus japonicus

Functional & Integrative Genomics - DNAJ proteins function as co-chaperones of HSP70 and play key roles in cell physiology to promote protein folding and degradation, especially under...     

香蕉MaASR1基因的抗干旱作用

ASR(ABA, stress, ripening induced protein)是一类响应植物干旱胁迫的关键转录因子, 在许多植物中已有报道, 然而尚未见香蕉(Musa acuminata)中ASR与抗旱作用的相关研究。该实验从香蕉果实cDNA文库中筛选出1个ASR基因, 即MaASR1(登录号为AY628102)。干旱胁迫下, 该基因在叶片中的表达量高于根部。将MaASR1转入拟南芥(Arabidopsis thaliana), Southern检测确定了两株独立表达的转基因株系(命名为L14和L38)。表型观察发现, 此两转基因株系的叶片变小且变厚; Northern和Western检测结果表明, MaASR1在L14和L38中表达。控水处理后, L14和L38的存活率及脯氨酸含量均高于野生型。经干旱胁迫和外源ABA处理后, 对MaASR1转基因株系中ABA/胁迫响应基因的表达分析, 发现MaASR1可增强转基因株系对ABA信号的敏感度, 但不能增强植株依赖于ABA途径的抗旱性。