Reduction of serum lipides and lipoproteins by ethionine feeding in the dog

(i) The effects of daily oral administration of 125 mg of DL-ethionine upon the serum lipides and lipoproteins of dogs were studied. (ii) The feeding of the ethionine resulted in a prompt reduction in the levels of serum fatty acids, phospholipides, and cholesterol. See PDF for Figure At the end of 25 days, negligible amounts of these lipides remained in serum. (iii) A reduction in the levels of low- and high-density lipoproteins also resulted from the feeding of ethionine. In general, the extent of reduction in all lipoprotein fractions paralleled that observed in lipides. (iv) The removal of ethionine from the diet led to a prompt restoration of the concentrations of all lipide and lipoprotein constituents to normal.     

1-methyladenine biosynthesis in starfish ovary: action of gonad-stimulating hormone in methylation

Gonad-stimulating substance, a hormonal peptide released from the nervous system of starfishes, acts on the ovary to produce 1-methyladenine, an inducer of oocyte maturation. Addition of methionine to the incubation mixture of ovarian fragments and gonad-stimulating substance enhanced the production of 1-methyladenine, whereas ethionine inhibited it. Incubation of ovarian tissue with methionine alone failed to produce 1-methyladenine. Use of a radioactive label showed that methionine is a methyl donor in the biosynthesis of 1-methyladenine, suggesting that gonad-stimulating substance is involved in the methylation process.     

输气管道水化物堵塞的预防和处理

阐述了输气管道内水化物的成因，特性及游离水的来源，并对其进行了分析，根据分析结果，给出了预测管道内水化物形成区域的方法，提出了三项预防水化物的措施，（1）施工阶段避免过多使用弯管，（2）投产前增加吹扫次数，彻底清除水，（3）运行初期定期注入抑制剂，指出对已形成水化物的管道段，可采取尽快降低运行压力，加热，注醇和放空等措施进行处理。     

输气管道水合物的形成区域和预防

通过分析输气管道天然气水合物形成(NGH)的水分、温度和压力条件，给出了输气管道内NGH形成区域的预测方法。在NGH形成区域上，采取必要措施可预防NGH的形成。提出了脱水法、注醇法、加热法和降压法4种预防措施。     

Ethylene modulates stem cell division in the Arabidopsis thaliana root

The construction of multicellular organisms depends on stem cells-cells that can both regenerate and produce daughter cells that undergo differentiation. Here, we show that the gaseous messenger ethylene modulates cell division in the cells of the quiescent center, which act as a source of stem cells in the seedling root. The cells formed through these ethylene-induced divisions express quiescent center-specific genes and can repress differentiation of surrounding initial cells, showing that quiescence is not required for these cells to signal to adjacent stem cells. We propose that ethylene is part of a signaling pathway that modulates cell division in the quiescent center in the stem cell niche during the postembryonic development of the root system.     

17 beta-estradiol: inducer of uterine hexokinase

Administration of estradiol to ovariectomized rats induced new synthesis of uterine hexokinase which was prevented by actinomycin D, 5-fluorouracil, cycloheximide, or ethionine. The estradiol-induced increase in uterine hexokinase activity was detectable as early as 4 hours. The increase in enzyme activity was dependent upon the dose of the hormone. The evidence indicates that the increased hexokinase activity induced by 17beta-estradiol may entail an acceleration of the synthesis of certain RNA species.     

A3钢储罐二氯乙烷的腐蚀分析及其储存方法

在用A3储罐储存二氯乙烷的过程中，储罐发生了严惩的腐蚀并导致了泄漏 。通过探伤检测及宏观检查，发现腐蚀层呈层状排列，有钟乳状突起。分析了二氯乙烷对A3钢的腐蚀机理，指出腐蚀的主要原因是二氯乙烷储存方法不当，当二氯乙烷氧化产生的HCl吸收水分，形成盐酸产生电化学腐蚀。根据分析结果，制定了二氯乙烷的安全储存方法。     

Coking- and sintering-resistant palladium catalysts achieved through atomic layer deposition

We showed that alumina (Al(2)O(3)) overcoating of supported metal nanoparticles (NPs) effectively reduced deactivation by coking and sintering in high-temperature applications of heterogeneous catalysts. We overcoated palladium NPs with 45 layers of alumina through an atomic layer deposition (ALD) process that alternated exposures of the catalysts to trimethylaluminum and water at 200°C. When these catalysts were used for 1 hour in oxidative dehydrogenation of ethane to ethylene at 650°C, they were found by thermogravimetric analysis to contain less than 6% of the coke formed on the uncoated catalysts. Scanning transmission electron microscopy showed no visible morphology changes after reaction at 675°C for 28 hours. The yield of ethylene was improved on all ALD Al(2)O(3) overcoated Pd catalysts.     

乙烯介导的防卫信号途径研究进展

乙烯是植物体内主要的防御信号途径之一。从乙烯的合成、乙烯与其相关物质在植物信号传导途径、植物体防御体系及乙烯在植物体中的防卫作用方面对乙烯介导的防卫信号途径的研究进展进行了阐述,并对乙烯介导的防卫信号途径研究进行了展望。     

Reformation of functional liver polyribosomes from ribosome monomers in the absence of RNA synthesis

The administration to rats of the ethyl analog of methionine, ethionine, results in the rapid decrease in the hepatic concentration of adenosine triphosphate followed by an extensive disaggregation of polysomes to ribosome monomers and a concomitant inhibition of protein synthesis. These effects are readily reversed by the injection of methionine or precursors of adenine nucleotides such as adenine. The reformation of liver polyribosomes in such animals following the administration of adenine plus methionine was found to occur under conditions in which new RNA synthesis was markedly inhibited. Free messenger RNA without attached ribosomes must be capable of remaining functionally active in the liver cytoplasm for many hours.     

Synthesis gas: a raw material for industrial chemicals

Rapid increases in the price of imported crude oil have accelerated a shift in the raw material base for chemical feedstocks from natural gas to crude oil to coal. Widespread use of ethylene as a feedstock has depended on the availability at attractive prices of natural gas and petroleum. As the resource base shifts from natural gas and petroleum to coal, ethylene is being replaced by synthesis gas (a mixture of hydrogen and carbon monoxide of varying composition), which can be manufactured directly from any of these carbonaceous sources. This trend is expected to accelerate in the 1980's. Organics likely to be produced from synthesis gas include ethanol, ethylene glycol, and vinyl acetate.     

毛细管柱气相色谱法测定橡胶树胶乳中的乙烯含量及其变化

采用毛细管柱气相色谱法测定橡胶树胶乳中的乙烯含量,并初步测定了乙烯刺激割胶不同割次的乙烯含量及其变化.该方法的线性范围为11.6-581.4μL.L-1,检测限为1.12μL.L-1,相对标准偏差(RSD)为1.01%.橡胶树采用乙烯利刺激(S/2 D/2+2.5%ET),涂药后第1-3割次的胶乳乙烯释放量分别为:151.6、31.1、17.5μL.L-1,而未经刺激的橡胶树(对照)乙烯含量低于检出限;第1-3割次的胶乳乙烯生成速率分别为:2.823、0.578、0.324 nL.g-1.h-1,表明经乙烯利刺激后,胶乳中的乙烯含量大量增加,生成速率发生了明显变化,均大于对照,且随割次的增多而降低.     

预冷对哈密瓜采后乙烯释放和呼吸强度的影响

[目的]以研建哈密瓜预冷工艺为目标,依据预冷对果实采后呼吸与内源乙烯的影响,确定哈密瓜采后预冷工艺的基本参数.[方法]测定中熟品种抗病86哈密瓜预冷过程果实温度、呼吸强度和乙烯释放量的变化.[结果]3℃条件通风预冷过程中,乙烯释放量和呼吸强度与温度同步下降,果实各部位降温速率大小顺序为:果皮＞近果皮果肉＞近种腔果肉＞种腔;温度、呼吸强度与乙烯释放量下降的最快时段为预冷的前4h,果实各部位降温幅度为39.55;～66.42;,乙烯释放量和呼吸强度降幅分别达到82.69;和56.41;,随后各指标降幅明显减小.[结论]预冷12 h左右,果实各部位的温度、呼吸强度和乙烯释放量下降幅度均超过70;.     

钙钠离子对高粱和小麦乙烯释放的影响

本文阐述了钙、钠离子对小麦、高粱抗旱性不同的品种叶片与根乙烯释放的影响。钙和钠离子对小麦和高架根的乙烯释放有明显的抑制效应。钠离子胁迫下,小麦根乙烯释放量多于高粱根;钙离子胁迫下则以高粱根乙烯释放量为多。钙或钠离子胁迫下,高粱或小麦不抗旱品种根乙烯释放量多于抗早品种。就叶片乙烯释放而言,高粱乙烯释放量少于小麦。两离子对高粱抗旱品种叶片乙烯释有促进作用,对不抗旱品种影响甚微。小麦不抗旱品种叶片乙烯释放为钙钠处理所抑制。胁迫下两种作物抗旱品种叶片的乙烯释放量高于其不抗旱品种的。这些结果表明,植物的乙烯释放对盐分胁迫的反应随组织器官和基因型而异。     

乙烯与猕猴桃果实的后熟软化

研究猕猴桃果实成熟进程中内源乙烯释放规律以及外源乙烯处理对果实后熟软化的效应,以 探讨乙烯与猕猴桃果实后熟软化的关系．结果表明,猕猴桃果实采后后熟软化分为前期的软化启动阶段 和后期的快速软化阶段,乙烯在果实成熟过程的作用主要是加速了快速软化阶段的果实软化进程,而与 软化启动阶段的果实软化启动无明显相关;外源乙烯可加速猕猴桃果实后熟软化,其调控机理并不是通 过促进果实内源乙烯的合成而实现的。     

乙烯吸收剂处理对柿果实采后生理效应的影响

通过用乙烯吸收剂吸收贮藏环境中乙烯的方法,研究了火柿果实成熟软化过程中乙烯对果肉硬度、呼吸速率、PE活性、PG活性和CX活性的影响,探讨了果实软化的机理。结果表明,乙烯吸收剂处理能有效地清除贮藏环境中的乙烯,降低果实的呼吸速率和乙烯释放速率,抑制PG、PE和CX的活性,有效地延缓果实硬度的下降速率。乙烯在柿果实软化衰老中起着主导作用。     

乙烯代谢途径中基因表达与器官脱落研究进展

器官脱落是一种由各种因素共同调节的复杂生理过程,多种激素对其都有影响,其中乙烯对脱落的影响最大.乙烯含量的上升和器官脱落正相关,但乙烯含量的上升和器官脱落之间并非相邻的两个步骤.器官脱落首先须使植物体本身乙烯合成量增加,之后通过乙烯受体基因和乙烯进行结合,再通过乙烯信号传递体把乙烯上升信号传递下去,从而引起离区细胞壁水解酶活性增强和基因表达量上升,进而导致离区细胞壁发生破碎,最终导致器官脱落.综述了乙烯代谢途径中的乙烯合成、膜上乙烯受体、乙烯膜内信号传递体与器官脱落的研究进展.     

固定化甲烷氧化菌细胞催化乙烯环氧化反应动力学研究

以甲基弯菌IMV 3011(Methylosinus trichosporium IMV 3011)为试验对象,活性炭为载体,吸附法制成固定化甲烷氧化菌细胞,催化乙烯环氧化反应,研究内外扩散对环氧化速率影响,通过控制单一变量法,建立该反应幂指数速率方程。结果表明,通过Mears方程验证,可忽略内扩散对环氧化速率影响;当转速高于200 r·min~(-1)时,可忽略外扩散对环氧化速率影响。乙烯环氧化反应幂指数速率方程中,各因素反应级数分别为:乙烯0.6983、氧气0.2715、环氧乙烷-1.0185、催化剂0.5635,通过阿伦尼乌斯方程拟合线得到反应活化能22.575 k J·mol~(-1)。利用幂指数速率方程可计算乙烯环氧化反应环氧化速率,拟合试验表明,测定值与计算值具有良好拟合性。     

红富士苹果采后生理研究

对红富士苹果采后呼吸强度、内源乙烯含量、细胞间隙ＣＯ２浓度以及果实对外源乙烯反应进行的研究表明：红富士苹果采后呼吸作用水平低,呼吸峰出现时间晚,峰值低;内源乙烯含量水平低,乙烯峰值出现时间晚,峰值小;对外源乙烯刺激不太敏感;细胞间隙ＣＯ２浓度与环境ＣＯ２浓度比值高,并随贮期延长而增大,表现出独特的采后生理特点。     

转反义LeEIL2基因番茄果实采后部分生理特性

普通番茄和转反义LeEIL2基因番茄不同成熟度果实研究结果表明,转反义LeEIL2基因番茄有效抑制了LeEIL2基因的表达,其果实和叶片表现出与普通番茄不同的生理特性:采后果实的呼吸强度和乙烯释放量受到抑制,离体叶片的伤乙烯释放量明显降低;果实中ACC合成酶与ACC氧化酶活性以及ACC含量明显下降,从而抑制了乙烯的生物合成途径,延缓了果实的成熟衰老进程。