缺氧对离体鸡胚前脑神经细胞生长的影响

在缺氧(95％N_2和5％CO_2)条件下进行8d鸡胚前脑的纯神经细胞培养。培养24,48和72h后,MTT微量比色法检测显示,甲(目替)明显减少,表明神经元已遭严重损害,同时,培养液中葡萄糖被急剧地消耗。但是,即使把糖浓度提高到800—1200mg/100ml,缺氧仍造成神经细胞死亡。结果提示,胚胎脑神经细胞对缺氧敏感,胶质细胞对缺氧神经元的保护可能不在于提供糖原。     

PCR libraries of ancient DNA using a generalized PCR method.

We describe a generalized PCR method that will amplify fragments of DNA without any knowledge of sequence using a single primer. Although we are presently using this method to amplify DNA fragments isolated from ancient preserved tissues, in effect, producing PCR libraries, it may prove to have other applications.     

The use of a multichannel scaling method to detect radioactive species in spread monolayers

This study describes a simple and inexpensive method for monitoring radioactive species spread as monolayers at the air/water interface. The combination of a discriminator and multichannel scalar counter with a personal computer functions to unify all measurements, to simplify the operational process and data acquisition, and to provide a real-time display of the data. Its use is demonstrated by following the hydrolysis of L-alpha-[1-14C]dioleoyl phosphatidylcholine by the enzyme, phospholipase A2, isolated from the porcine pancreas.     

辽宁省玉米复合农业气象灾害判识及特征

玉米生产过程中常常遭受复合农业气象灾害,为了解辽宁省玉米复合农业气象灾害发生规律和特征,本研究对复合农业气象灾害进行定义和分类,对1961-2017年辽宁省50个气象站玉米生长季的复合农业气象灾害发生情况进行判识,探讨典型年复合农业气象灾害对玉米产量的影响.结果表明:1961-2017年,大部分年份辽宁省玉米复合农业气...     

蜥蜴类皮肤化石在中国的首次发现及一新属记述(蜥蜴亚目:石龙子次亚目)

晚侏罗世蜥蜴化石在世界范围内分布较为贫乏,而这个时期的化石在研究早期蜥蜴类的形态及分类演化方面具有重要意义。记述了河北北部晚侏罗世蜥蜴化石一新属种：丽热河蜥Ｊｅｈｏｌａｃｅｒｔａｆｏｒｍｏｓａｇｅｎ．ｅｔｓｐ．ｎｏｖ．,该化石保存有大面积精美的皮肤鳞片。这是蜥蜴类鳞片化石在我国的首次发现,同时也为人类认识早期蜥蜴动物的表皮特征提供了珍贵的材料。由于躯干具有较大的方鳞,该蜥蜴应隶属于石龙子次亚目Ｓｃｉｎｃｏｍｏｒｐｈａ,似可归入蜥蜴科Ｌａｃｅｒｔｉｄａｅ,有待证实。模式标本采自河北平泉县杨树岭镇石门村义县组下部地层中,保存于中国地质博物馆。     

牙龈卟啉单胞菌编码基因重注释研究

为了确保牙龈卟啉单胞菌生物大分子信息的准确性,对NCBI数据库中的3株牙龈卟啉单胞菌的注释信息进行研究。首先,准备好蛋白质编码与非编码序列正负样本,用基于Z曲线理论的Fisher判别法对正负样本集进行训练,确定一个判断ORF编码或非编码的阈值t0,由阈值作为判别条件来识别所有的ORFs,判断基因片段是否具有编码蛋白质的功能,由此阈值为判别标准排除掉3株牙龈卟啉单胞菌基因组中错误的基因注释信息。然后,用Prodigal基因预测软件对牙龈卟啉单胞菌进行基因预测,基因预测结果与原始功能已知基因进行比对,挑选出具有不同5’终端的ORFs,将这些具有不同5’终端的ORFs与功能已知的基因片段进行比对,找到重叠率小于20%的候选基因。最后,对这些候选基因用Blast进行序列比对找到满足条件的新基因,并为这些新基因添加功能注释信息。基于以上方法共排除了117个非编码的开放式阅读框,并找到了30个NCBI数据库中缺失的编码蛋白质的新基因。     

Purification and characterisation of epithiospecifier protein from Brassica napus: enzymic intramolecular sulphur addition within alkenyl thiohydroximates derived from alkenyl glucosinolate hydrolysis

Epithiospecifier protein (ESP), a ferrous ion dependent protein, has a potential role in regulating the release of elemental sulphur, nitriles, isothiocyanates and cyanoepithioalkanes from glucosinolates. Two classes of ESP polypeptides were purified with molecular masses of 39 and 35 kDa, and we show that the previously reported instability was conditionally dependent. The 39 kDa polypeptide was made up of two distinct isozymes (5.00, 5.14) whilst several were present for the 35 kDa form of ESP (5.40-5.66). An anti-ESP antibody reacted with both the 39 and 35 kDa ESP forms in Brassica napus and strongly with a polypeptide corresponding to the 35 kDa ESP form in Crambe abyssinica, but did not detect any ESP in Sinapis alba or Raphanus sativus. A cytochrome P-450 mediated iron dependent epoxidation type mechanism is suggested for ESP.