黄连木果实挥发油化学成分GC-MS分析

采用水蒸汽蒸馏法从黄连木果实中提取挥发油,利用GC-MS联用仪对黄连木果实挥发油的化学成分进行研究,共分离到60个组分,鉴定了其中的41个,占挥发油总量的89.788%。黄连木果实挥发油主要成分是(Z)-3,7-二甲基-1,3,6-辛三烯(13.529%),4-甲基-1-(1-甲基乙基)-3-环己烯-1-醇(12.229%),(E)-3,7-二甲基-1,3,6-辛三烯(7.704%),D-柠檬烯(7.461%),1-甲基-4-(1-甲基乙基)-1,4-环己二烯(6.537%),3-蒈烯(5.314%)等。     

高产醋酸菌的筛选及其形态生化特征研究

从天然发酵醋醅中分离得到了32株醋酸菌,经初筛、复筛产酸试验,筛选出了J4和J82株醋酸菌.采用紫外线诱变处理始发J4菌株,经分离筛选获得产醋酸能力高的醋酸菌J4-1和J4-4,产酸量分别为85.44 g/L和87.56 g/L,J4-4产酸量比菌株J4(84.19 g/L)提高了4%,并对J4-4菌株的形态生化特征进行了研究.     

The Related Research of the Genes of Gibberellin Receptor(GID1) in Plant

The hormone gibberellin(GA) plays an important role in modulating diverse processes throughout plant development.Gibberellin(GA) perception is mediated by GID1(GA-INSENSITIVE DWARF1),a receptor that shows similarity to hormone-sensitive lipases.It has been postulated that plants have two types of GA receptors,including soluble and membrane-bound forms.In recent years,significant advances have been made in the research of Gibberellin Receptor(GID1).This article highlights recent advances in the molecular structure of Gibberellin Receptor(GID1),Molecular Interactions between the Gibberellin Receptor(GID1) with DELLA,Cloning and expression of GA receptors(GID1),function identification of GA receptor gene(GID1).These discoveries open new prospects for the understanding mechanism of GA receptors(GID1) in plants.     

薄荷醇酯类衍生物的合成及其驱蚊活性的初步研究

由薄荷醇合成了乙酸薄荷酯和丙酸薄荷酯,这2个衍生物都具有较好的香气性质,它们的结构均用IR,MS,1HNMR及13CNMR分析进行了表征。采用国标的方法对薄荷醇及其乙酸酯和丙酸酯的驱蚊活性进行了测定,结果显示薄荷醇对白纹伊蚊(Aedes albopictus)具有一定的驱避效果,而薄荷醇的乙酸酯和丙酸酯的驱避活性很低。     

蓖麻叶挥发油化学成分分析

采用水蒸汽蒸馏法从蓖麻叶中提取挥发油,利用GC-MS联用仪对蓖麻叶挥发油的化学成分进行研究,共分离到52个组分,鉴定了其中的31个,占挥发油总量的77.223%。蓖麻叶挥发油主要成分是壬醛(14.718%)、二环[3.2.0]庚-2-酮(7.773%)、2,4-癸二烯醛(6.237%)、(E)-4-(2,6,6-三甲基-1-环己烯-1-基)-3-丁烯-2-酮(6.056%)、(E)-2-癸醛(5.967%)、(E)-6,10-二甲基-5,9-十一碳二烯-2-酮(5.063%)等。     

籼稻矮源遗传研究——论双桂、丛桂等品种矮生性的遗传性质

本试验研究了双桂1号、双桂36号和丛桂226等半矮生性品种的株高遗传。结果表明,其半矮生性受二对基因互补作用的控制,基因型为sd-1 sd-1 dg(t)dg(t),sd-1和dg(t)分别渊源于矮仔占和桂阳矮1号。研究证明,“丛生快长型”籼稻育种是我国籼稻育种矮源利用的新发展。     

不同激素浓度组合对蚕豆(Vicia faba)叶片离体培养的影响

本文研究的是不同激素浓度组合对蚕豆叶片离体培养的影响,得到的结果是:1.NAA 能诱导叶片外植体产生愈伤组织并能使愈伤组织分化成苗;2.KT 与 NAA 配合使用,对诱导叶片外植体产生愈伤组织的效果更好,诱导频率可达100%,但对苗的分化最好的组合是1mgL~(-1)KT 2mgL~(-1)NAA,分化率高达33.33%;3.BA 与 NAA 配合使用对诱导外植体产生愈伤组织的效果比单用 NAA 要好,但 BA 对愈伤组织分化幼苗有抑制作用;4.在 KT 与 NAA 配合使用时,不同部位的叶片和不同品种的叶片,在愈伤组织诱导率及发根数这两个方面没有明显差别。     

中药材白鲜皮的成分鉴定分析初报

文章对白鲜皮(Dictamnus dasycarpus Turcz.)化学成分进行了研究,时其乙醇提取物的乙酸乙酯萃取部分经硅胶柱层析、重结晶等手段,分离得到5个单体(A、B、C、E和G),通过碳谱、氢谱等核磁手段鉴定:A 为梣酮(Fraxinellone),E 为白鲜碱(Dictamine),G 为黄柏酮(Obacunone).其余化合物正在鉴定中.     

A hydrophobic transmembrane segment at the carboxyl terminus of thy-1

The mode of integration of the glycoprotein thy-1 within the cell membrane has been controversial due to an apparent lack of a transmembrane hydrophobic segment. Rat and mouse complementary DNA and genomic clones encoding the thy-1 molecule have been isolated and sequenced. These studies have enabled us to determine the intron-exon organization of the thy-1 gene. Furthermore, they have revealed the existence of a sequence which would encode an extra segment (31 amino acids) at the carboxyl terminus of the thy-1 molecule. These extra amino acids include a 20-amino acid hydrophobic segment which may be responsible for integration of thy-1 within the plasma membrane.     

Erratum

In the report "Cloud droplet deposition in subalpine balsam fir forests: Hydrological and chemical inputs" by G. M. Lovett et al. (24 Dec., p. 1303), two errors appeared in Table 2 on page 1304. The cloud deposition of SO(4)(2-), incorrectly reported as 275.8 kg ha(-1) year(-1), should have been 137.9 kg ha(-1) year(-1). The percentage of the sum contributed by clouds, reported as 81 for SO(4)(2-), should have been 68.     

Prevention of translational frameshifting by the modified nucleoside 1-methylguanosine

The methylated nucleoside 1-methylguanosine (m1G) is present next to the 3' end of the anticodon (position 37) in all transfer RNAs (tRNAs) that read codons starting with C except in those tRNAs that read CAN codons. All of the three proline tRNA species, which read CCN codons in Salmonella typhimurium, have been sequenced and shown to contain m1G in position 37. A mutant of S. typhimurium that lacks m1G in its tRNA when grown at temperatures above 37 degrees C, has now been isolated. The mutation (trmD3) responsible for this methylation deficiency is in the structural gene (trmD) for the tRNA(m1G37)methyltransferase. Therefore, the three proline tRNAs in the trmD3 mutant have an unmodified guanosine at position 37. Furthermore, the trmD3 mutation also causes at least one of the tRNAPro species to frequently shift frame when C's are present successively in the message. Thus, m1G appears to prevent frameshifting. The data from eubacteria apply to both eukaryotes and archaebacteria.     

黄连木果柄挥发油化学成分GC-MS分析

在已分析黄连木果实挥发油化学成分的基础上,对黄连木果柄挥发油化学成分进行GC-MS分析,以对二者挥发油成分进行比较。采用水蒸汽蒸馏法从黄连木果柄中提取挥发油,利用GC-MS联用仪对黄连木果柄挥发油的化学成分进行分析,共分离到50个组分,鉴定了其中的37个,占挥发油总量的91.917%。黄连木果柄挥发油主要成分是[1S-(1,α7,α8 aβ)]-1,2,3,5,6,7,8,8 a-八氢-1,4-二甲基-7-(甲基乙烯基)-薁(11.979%),3-蒈烯(10.640%),β-水芹烯(9.504%),1-乙烯基-1-甲基-2,4-二(1-甲基乙烯基)-环己烯(7.760%),β-蒎烯(6.227%),α-蒎烯(6.065%),D-柠檬烯(5.070%)等。黄连木果实和果柄挥发油的主要化学成分组成和含量有差异,但主要成分差别不大。     

植物耐旱性及其机理

本文综合评述了植物的各种耐旱机理。依据植物对干旱胁迫的反应行为,把植物的耐旱机理分为3个基本类型:(1)逃避干旱;(2)高水势延迟脱水耐旱;(3)低水势忍耐脱水耐旱。逃避干旱的植物(如沙漠短生植物)具有在严重的干旱胁迫发生之前就完成其生命周期的能力,但它们的特点本文未加以讨论。而着重讨论了忍耐干旱的植物的耐旱特点。高水势延迟脱水的植物是以保持水分吸收和减少水分丧失为其主要的耐旱特征。而低水势忍耐脱水的植物则是以保持膨压和原生质忍耐脱水为其主要特征。     

栎属二新变种

本文在研究栎属(Quercus L.)槲栎组(Sect.Robur Loud.)的基础上报道了一新变种,陕西槲栎(Quercus aliena Bl.var.shaanxiensis W.H.Zhang)星毛枹栎(Quercus glandulifera Bl.var.stellatopilosa W.H.Zhang)并讨论了有关问题。     

Fluorocitrate inhibition of aconitase: relative configuration of inhibitory isomer by x-ray crystallography

The fluorocitrate isomer that is a strong inhibitor and inactivator of aconitase has been shown by x-ray crystallographic studies on the rubidium ammonium salt to have the configurations (1R : 2R) or (1S : 2S) 1-fluoro-2-hydroxy-1,2,3-propanetricarboxylic acid. A possible mechanism for the action of fluorocitrate is proposed which involves the 1R : 2R isomer suggested from biochemical data.     

两种模式酵母中可分解丙酮醛的GLO3的特性及鉴定

GLO3是一种不依赖辅助因子就可分解丙酮醛的酶,有研究表明大肠杆菌的EcHsp31和人的HsDJ 1均属于这种GLO3。丙酮醛是细胞糖酵解过程中产生的一种有毒的副产物,乙二醛酶Ⅰ(GLO1)和乙二醛酶Ⅱ(GLO2)在谷胱甘肽(GSH)的辅助下可以降解细胞内丙酮醛,乙二醛酶Ⅲ(GLO3)不需要GSH的辅助可以直接降解MG。研究真菌的GLO3降解丙酮醛的机制,对认识和研究因丙酮醛引起的疾病具有重要的指导意义。研究表明,真菌中GLO3同源蛋白十分复杂,Hsp31在真菌中广泛存在,DJ 1只在部分真菌中存在,进化树结果支持GLO3的同源蛋白Hsp31和DJ 1是一种趋同进化。对模式真菌酿酒酵母的ScHsp31和裂殖酵母SpDJ 1进行GLO3的酶活测定和HPLC产物检测表明,这两种蛋白均具有GLO3的特性。     

氯乙烯—丙烯酸丁酯共聚物热降解动力学的研究

本文是研究氯乙烯(VC)—丙烯酸丁酯(BA)共聚物的热降解动力学.考查了升温速率(β),气氛对热降解的影响.在氮气气氛中,共聚物(VC—BA)的热降解反应是吸热反应,降解反应分两步进行.第一步是脱除支基,反应级数(n)为1.2级,活化能(E)为113KJ/mol;第二步是主链断裂,反应级数(n)随升温速率(β)的增大而减小.在空气气氛中,共聚物(VC—BA)的热降解反应是放热反应,降解分三步进行(第三步未完成).第一步也是脱除支基,反应级数(n)为1.0级;活化能(E)为111.2KJ/moα,第二步亦是主链断裂,反应级数也随β增大而减小.     

Evidence for a phytotoxic hydroxy-aluminum polymer in organic soil horizons

The toxicity of A1 that has been mobilized in soil, streams, and lakes through acid deposition primarily has been attributed to mononuclear A1 species. Polynuclear A1 species are more toxic than mononuclear species, but they have not been considered to be significant in the environment. Aluminum-27 nuclear magnetic resonance (NMR) spectra of forested spodosol soil horizon samples show the presence of polynuclear A1O(4)A1(12)(OH)(24)(H(2)O)(12)(7+). The AlO(4)A1(12)(OH)(24)(H(2)O)(12)(7+) species accounted for 30 percent of the aqueous A1 observable by NMR, and this could make a significant contribution to the toxicity of the A1 in these soils.     

Meteorite fail at pueblito de allende, chihuahua, Mexico: preliminary information

Specimens from the meteorite fall at 1:05 a. m., on 8 February 1969 at Pueblito de Allende, Chihuahua, Mexico, have been recovered. The meteorite is a chondrite (C3 and C4) with both opaque and microcrystalline matrices. Specimens were brought to a low background gamma counter less than 4 (1/2) days after the fall, and gamma rays from short-lived isotopes have been observed.     

A Rotationally Resolved Fluorescence Excitation Spectrum of all-trans-1,4-Diphenyl-1,3-butadiene

Band 1 in the jet-cooled one-photon S(1) <-- S(0) fluorescence excitation spectrum of all-trans-1,4-diphenyl-1,3-butadiene has been rotationally resolved with a molecular beam laser spectrometer. Both the orientation of the optical transition moment and the rotational constants of the two vibronic levels have been measured. The molecule shows no evidence of being significantly distorted from a C(24) geometry when it is low in the vibrational manifolds of either of the two electronic states.