Restorable variation of cytoplasmic type of male sterile line in rice byin vitro culture

Rice male sterile (MS) lines, IR66707A and IR69700A, which possess the cytoplasm of Oryza perennis and O. glumaepatula respectively, belong to the cytoplasmic type. Their sterility could be maintained but not be restored. By somatic cell culture of these two MS lines, 47 somaclones with 465 R₁ plants were obtained. All of the 465 R₁ plants were sterile in the spring season in Guangzhou. According to the expression of the R₁ plants and the level of similarity to their donor parents, they could be divided into three types. The plants of type Ⅰ were male sterile. The sterility of some somaclones of this type could be restored by the test crossing varieties or alternated to fertile by changes of some environmental conditions. The hybrid F₁ of test cross from the MS somaclones in type Ⅰ was fertile while the hybrid F₁ from the donor MS lines was still sterile. The R₁ plants of type Ⅱ were similar to the donor parents and also male sterile. The hybrid F₁ from all of the plants of type Ⅱ crossed to test variety were still sterile, so they did not possess restorability. For the somaclone of type Ⅲ, all of R₁ plants were sterile in both male and female organs. No seed was set in both conditions of self and cross pollination. The fact that the restorable variants obtained in the cytoplasmic type of MS lines of rice by in vitro culture reported here should be the first sample in somaclonal variation in plant kingdom.     

Paleo-environmental study on the growth of magnetotactic bacteria and precipitation of magnetosomes in Chinese loess-paleosol sequences

405 samples were collected from L5-S5-L6 in consideration of obvious variations in susceptibility of the geological sections, which are section Xifeng in Gansu Province and section Duanjiapo in Shaanxi Province for study of magnetotactic bacteria (MB) and magnetosomes (MS) in Chinese loess-paleosol sequences. MB in each sample were observed by TEM after being cultured under 8-18℃, room temperature (RT), 25℃, 26℃ and 30℃ conditions. In general, MB are distributed widely in loess-paleosol sequences, fewer in loess layers with predomination of vibriod in shape. However, there are more MB in paleosol layers with morphological varieties such as roddish, vibriod and occasionally approximately coccus. The magnetosomes (MS) in MB of paleosol are usually arranged in chains along the cells. It was also found that MB growth and MS formation are associated with the environment in which MB live. It can be inferred from the distributions of MB and MS that the paleoclimates fluctuated during the formation of loess-paleosol sequences in the Chinese Loess Plateau. The climate became gradually warmer but displayed more frequent fluctuations from the northwest to the southeast of the Plateau .     

GC/MS/MS鉴别2-氨基吡啶硝化产物的研究

2-氨基吡啶硝化产物2-氨基-3-硝基吡啶和2-氨基-5-硝基吡啶的一级质谱图接近,单纯通过一级质谱图较难区分这两种异构体.利用离子阱质谱的串联质谱技术对2-氨基-3-硝基吡啶和2-氨基-5-硝基吡啶在离子阱内以He作碰撞气进行碰撞诱导裂解,所得的二级质谱图表明,两者之间存在明显的差别,可用于2-氨基吡啶硝化产物2-氨基-3-硝基吡啶和2-氨基-5-硝基吡啶的鉴别.     

聚氧乙烯型非离子表面活性剂的电喷雾质谱行为

聚氧乙烯型表面活性剂是一类重要的非离子型表面活性剂,易与阳离子形成加合离子[M＋X]^＋。应用电喷雾飞行时间质谱仪（ESI—TOF—MS）,以直接进样的方式,对壬基酚聚氧乙烯醚加合离子进行了研究。通常在谱图中可见钠、钾加合离子[M＋-Na]^＋、[M＋K]^＋。样品中的钠、钾离子的浓度影响对应加合离子的谱峰强度。样品中加入．MgCl2,可在谱图上观察到[M＋MgCl]^＋离子的谱峰。用高分辨电喷雾质谱确定[M＋18]^＋峰对应于[M＋NH4]^＋。     

基于信道软输出及信源参数相关性的联合语音解码

提出一种基于接收端的联合语音解码算法,根据信道或信道解码提供的参数软输出值,以及语音编码参数的冗余量计算接收参数的后验概率;利用后验概率基于MAP或MS准则进行参数估计,最佳估计值进行语音解码.仿真中采用G.711和GSM EFR两种语音编码标准,结果表明联合解码算法显著提高了解码语音信噪比.     

Detection of sialylated N-Linked glycans by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Native and methyl-esterified sialylated glycans were analyzed with 2,4,6-trihydroxyacetophenone（THAP）and 2,5-dihydroxybenzoic acid（DHB）as matrix by a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer（MALDI-TOF MS）.High quality negative-ion spectra of commercial sialylated glycan were obtained with THAP as matrix.Detection limit of the glycan was less than 0.1 pmol.After methyl esterification of sialic acid（SA）residue,sialylated glycans were detected sensitively in the positive-ion mode using DHB as matrix.Neutral and sialylated glycans from the mixture of asialofetuin and fetuin were methylesterified and simultaneously recognized in one manipulation.Methyl esterification of SA residue offers a convenient and sensitive way to identify the structure of N-linked glycans for glycan profiling.     

黄褐毛忍冬花蕾挥发油化学成分分析

本文用GG/MS法对黄褐毛忍冬干、鲜花蕾挥发油化学成分进行了比较分析,结果表明,从干、鲜花蕾分别挥发油中分别分离出52、29种挥发性成分,共确定出53种化合物,并用峰面积归一化法测量了各化学成分在挥发油中的相对百分含量.黄褐毛忍冬干、鲜花蕾挥发油共有28种相同的化学成分,如L芳樟醇、α-松油醇、香叶醇等,而且含量都相对...     

柑橘皮精油提取分离及成分测定

为提高柑橘原材料利用率以增加其经济效益,以柑橘皮为原料,研究柑橘皮精油的成分,用水蒸气蒸馏法提取柑橘皮中的精油,并利用气质联用仪对提取的精油成分进行测定.结果表明,柑橘皮精油含33种成分,其主要成分为柠檬烯.     

超高效液相色谱-串联质谱法检测禽畜肉中的氯霉素残留

 研究了一种针对禽畜肉中氯霉素残留量的超高效液相色谱-串联质谱联用分析方法.本方法采用乙酸乙酯萃取禽畜肉中的氯霉素,提取液氮吹至干后用超纯水溶解样品残渣,然后用HLB小柱进行固相萃取,经过净化的样品通过超高效液相色谱进行分离,然后用电喷雾质谱负离子多反应监测模式对氯霉素进行检测.该方法的检出限为0.0025μg/kg,添加水平为0.1~5.0μg/kg时,加标回收率为75.8%~82.5%,相对标准偏差小于10%.该方法具有灵敏度高、选择性好、分析时间短等优点.