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tris-
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     campes-tris pv.
     pv.
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     Preparation of tris-adenosine triphosphate
     腺苷三磷酸-三羟甲基氨基甲烷(Tris-ATP)的制备
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     Synthesis of Tris (diethylamido) chlorosilane
     三(二乙胺基)氯化硅烷的合成
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     Synthesis of Indium Tris acetylacetonate
     乙酰丙酮铟的合成
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  tris-
Changes in the Antigenic Properties of Azospirillum brasilense Lipopolysaccharide, Induced by Addition of Tris-(hydroxymethyl)-a
      
Addition of tris-(hydroxymethyl)-aminomethane (Tris) into the culture medium of Azospirillum brasilense sp245 changes the antigenic properties of the lipopolysaccharide (LPS) isolated from the external membrane of the bacteria.
      
A stability study indicated that both crude enzyme preparations exhibited a good stability when exposed to a pH 7.2 tris-HCl buffer at 4°C for 4 h.
      
The activity of both forms of the enzyme in the reversed micelles significantly depended on the molarity of the buffer added to the medium (Mes-Tris-buffer, 50 mM NaCl).
      
The study of physicochemical properties of the enzyme showed that it is a homodimer with a subunit molecular weight of 68 ± 2 kD and a pH optimum of 7.5 (in Tris-HCl buffer).
      
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Purified succinic dehydrogenase is a metallo-flavin-adenine protein containing non-haematin iron.The flavin-adenine prosthetic group is firmly bound to the protein part of the enzyme and cannot be split from the latter by boiling in weak acid medium.By digesting with trypsin and chymotrypsin,however,the prosthetic group can be liberated in combination with a peptide chain.The product has been purified by a procedure which involves cresol extraction, mercuric sulphate precipitation,decomposition of the latter...

Purified succinic dehydrogenase is a metallo-flavin-adenine protein containing non-haematin iron.The flavin-adenine prosthetic group is firmly bound to the protein part of the enzyme and cannot be split from the latter by boiling in weak acid medium.By digesting with trypsin and chymotrypsin,however,the prosthetic group can be liberated in combination with a peptide chain.The product has been purified by a procedure which involves cresol extraction, mercuric sulphate precipitation,decomposition of the latter with hydrogen sulphide,followed by paper electrophoresis and paper chromatography.The purified product has been separated into four flavin-adenine peptides with different amino acid contents.One fraction with comparatively high mobility on paper electrophoresis and containing 12 amino acids(hydrolyzed in 6 N HCl) has an absorption spectrum with maxima at 265,350 and 450 mμ(compared with 260,375 and 450 mμ of FAD),the ratio of E_(260) and E_(450) mμ is equal to 3.87.The other three fractions has similar absorption spectra as that of the first,except for a slight shift of the 265 mμ maximum to 270 mμ.All the four flavin-adenine peptides contain cysteine and show a greenish yellow fluorescence in the u.v.light.The fluorescent intensity of the prosthetic group varies with pH and exhibits a maximum at pH 2.9.All fractions are inactive in the D-amino acid oxidase test and give on analysis 1 mole of adenine and 2.5 moles of phosphorus per mole of flavin.The pentose flavin ratio was much higher than that of FAD. Photolysis of the flavin-adenine peptides in alkaline solution yields a product which is insoluble in chloroform after acidification.Removal of the adenine results in the formation of flavin peptides.These facts indicate that the peptide chain is linked to the isoalloxazine nucleus of the prosthetic group.It is known that the absorption peak at 375 mμ of either FAD or FMN shifts to about 355 mμ at pH 12 due probably to the enolization of the keto group at the 2 or 4 position resulting in a redistribution of double bonds in the isoalloxazine ring system. In contrast our flavin-adenine peptide has the corresponding absorption maximum at 350 mμ which shows little positional shift at pH 12.This seems to suggest that the linking of the peptide chain to the isoalloxazine nucleus affects the enolization of the-NH-CO-,which may probably be the site of the linkage. The iron content increases with the specific activity of the enzyme during purification.Iron in the purified enzyme is present in the reduced state.It is firmly bound to the enzyme and can not be removed by prolonged dialysis against phosphate buffer or tris-hydroxymethyl-amino-methane buffer.Enzymatic activity is lost during prolonged incubation with o-phenanthroline or α,α'- dipyridyl and can not be recovered by incubation with Fe~(2+) or Fe~(3+).These experiments de- monstrate a close relationship between enzyme activity and the iron present in the enzyme molecule. The enzyme activity is lower in borate than in phosphate buffer.When 40 mM ethylenedi- aminetetraacetic acid is added to the borate buffer,the enzyme activity is raised almost to the level of that observed in the same concentration of phosphate buffer.The effect of EDTA and phosphate,when present together,is somewhat higher than of either alone.Alanine has a similar effect'as EDTA.

(一)用结晶胰蛋白酶及结晶胰凝乳蛋白酶处理净化的水溶性琥珀酸脱氢酶,经过对甲酚抽提,硫酸汞沉淀,硫化氢分解及纸电泳纸层析等方法净化得到四种带有不同肽链的腺嘌呤异咯嗪核苷酸。从它们的组成成份的分析以及它们的性质的观察,我们认为它们与已知的腺嘌呤异咯嗪二核苷酸略有不同。肽链是连接在异咯嗪上,其连接方式异于一般异咯嗪蛋白。肽链部份的氨基酸组成的分析结果,证明它们都含有半胱氨酸。(二)琥珀酸脱氢酶中的铁处于还原状态。铁与酶朊紧密结合,它与酶活力有密切关系。(三)无机磷可增加琥珀酸脱氢酶的活力,但琥珀酸脱氰酶的活力并不是必需依靠无机磷的存在,乙二胺四乙酸与丙氨酸也有类似无机磷的作用。

Chloroplasts, prepared from fresh, prechilled spinach leaves by the method of Jagendorf andAvron, were suspended in Tris buffer (25 μmoles, pH 8.4) containing MgCl_2 (6 μmoles), ADP(3 μmoles), P~(32)-labelled phosphate (3 μmoles), NaCl (25 μmoles) and the different cofactors. Totalvolume of the reaction mixture was 1.25 ml, containing 30-40 μg chlorophyll. Preliminary experi-ments showed that at the low illumination intensity for quantum yield determinations the optimal quan-ties of the co-factors were:...

Chloroplasts, prepared from fresh, prechilled spinach leaves by the method of Jagendorf andAvron, were suspended in Tris buffer (25 μmoles, pH 8.4) containing MgCl_2 (6 μmoles), ADP(3 μmoles), P~(32)-labelled phosphate (3 μmoles), NaCl (25 μmoles) and the different cofactors. Totalvolume of the reaction mixture was 1.25 ml, containing 30-40 μg chlorophyll. Preliminary experi-ments showed that at the low illumination intensity for quantum yield determinations the optimal quan-ties of the co-factors were: PMS or FMN, 0.005 μmole, vitamin K_3, 0.03 μmole, and of the Hilloxidants were: K_3Fe(CN)_6 0.6 μmole, TPN 0.2 μmole. Neon tube with dilute ammoniacal CuSO_4 solution and red-glass filters was used as light source.The wave length range was 620-660 mμ and the intensity was 6-8×10~3 ergs/cm~2/sec. Energydeterminations were made with a blackened constantin-copper thermopile, the absolute energy wascalibrated by the amount of heat produced electrically at the surface of the thermopile. The calcu-lated number of quanta was counter-checked by chlorophyllide actinometer according to Warburg.Light scattering was corrected by the ground glass method of Shibata. Phosphorylation rates weremeasured by ATP~(32) formed according to the method of Nielsen and Lehninger. No incorporation of P~32 was detectable in the dark. To avoid loss of activity preparations were conducted near 0℃ and experiments were completedwithin 10 minutes including isolation of chloroplasts. Representative results are given in Tab. 1. The following conclusions can be drawn. (1) The quantum requirement of cyclic photophosphorylation is between 2.9-6.5 (generally4-5) per molecule of ATP formed, irrespective of the co-factors used,. Although at high lightintensities PMS can be twice as active as vitamin K_3 or FMN, their quantum yields are the same. (2) Same numerical results are obtained with heat deproteinized leaf extract in place of co-factors. (Tab. 3). (3) Non-cyclic photophosphorylation with K_3Fe(CN)_6 or with TPN shows the same quantumrequirement of 4-6. (Tab.1). Apparently one and the same electron transport system is involvedin both types of phosphorylation and there exists probably only one phosphorylation site. However,the possibility of a second easily inactivated site is not excluded. (4) The simultaneously measured Hill reaction requires 9-12 quanta per molecule of O_2evolved with or without photophosphorylation (+ or -ADP, Tab.2). The result corroboratesthose of other workers. It further shows that under the conditions of the present experiment cou-pling is complete (P/2e = 1), and that no extra quantum is needed for the coupled formation ofATP. (5) The quantum requirement of both cyclic and noncyclic phosphorylation increased withdecreasing light intensity within the range used (1.3-6.0×103 ergs/cm~2/sec.) (Tab. 4), whereasthat of O_2 production by the Hill reaction remains constant, thus resulting in a progressive uncou-pling of phosphorylation from the electron transport chain. The relationship between the present results and the quantum requirement of photosyntheticCO_2-reduction is discussed. That at low intensities of illumination used in the present experimentsthe number of quanta required for 2 TPNH and 2 ATP formation equals to that of photosynthesisunder these conditions (~compensation point) indicated that cyclic production of ATP is perhapsnot involved and the extra ATP needed for CO_2-reduction in the Calvin cycle must come fromsome other source, e.g. respiration. That at higher light intensities (several times compensationpoint) the quantum requirement of photosynthesis increases is probably due to the coming into playof the photochemically inefficient cyclic photophosphorylation.

用菠菜叶绿体悬浮液,在红光下(620—660mμ,6—8×10~3尔格/厘米~2-秒)测定同位素P~(32)标记的无机磷酸进入ATP的强度,并根据吸收的光能量换算为形成一个分子ATP所需要的红光量子数。结果指出: (1)循环光合磷酸化作用,不论用何种辅助因素(PMS,维生素K_3,FMN),形成一个分子ATP的量子需要量均在4—5之间(最低一次获得2.9)。叶提取液代替辅助因素,结果亦同。(2)与希尔反应偶联的光合磷酸化作用(希尔氧化剂为K_3Fe(CN)_6或TPN)的量子需要量亦是4—6。同时测定的还原作用指出希尔反应中每放出一个分子O_2,需要8—12个红光量子,表示在试验条件下,二者是完全偶联的(P/2e?1)。没有磷酸化(不加ADP及P_i)时,希尔反应的量子需要量不变,表示偶联的ATP形成不需额外的光量子。(3)光强度减低,则循环与非循环光合磷酸化作用的效率随之降低,量子需要量增加,而希尔反应的效率则不变。从上述结果推论,两种光合磷酸化作用均是通过同一的电子传递系统,在此系统中仅有一个磷酸化部位,除非另有一个部位是极易破坏的。试验结果也对光合作用的量子需要量问题,供给可能的解释。在弱光下光合作用效...

用菠菜叶绿体悬浮液,在红光下(620—660mμ,6—8×10~3尔格/厘米~2-秒)测定同位素P~(32)标记的无机磷酸进入ATP的强度,并根据吸收的光能量换算为形成一个分子ATP所需要的红光量子数。结果指出: (1)循环光合磷酸化作用,不论用何种辅助因素(PMS,维生素K_3,FMN),形成一个分子ATP的量子需要量均在4—5之间(最低一次获得2.9)。叶提取液代替辅助因素,结果亦同。(2)与希尔反应偶联的光合磷酸化作用(希尔氧化剂为K_3Fe(CN)_6或TPN)的量子需要量亦是4—6。同时测定的还原作用指出希尔反应中每放出一个分子O_2,需要8—12个红光量子,表示在试验条件下,二者是完全偶联的(P/2e?1)。没有磷酸化(不加ADP及P_i)时,希尔反应的量子需要量不变,表示偶联的ATP形成不需额外的光量子。(3)光强度减低,则循环与非循环光合磷酸化作用的效率随之降低,量子需要量增加,而希尔反应的效率则不变。从上述结果推论,两种光合磷酸化作用均是通过同一的电子传递系统,在此系统中仅有一个磷酸化部位,除非另有一个部位是极易破坏的。试验结果也对光合作用的量子需要量问题,供给可能的解释。在弱光下光合作用效率高,可能是由于部份ATP来自呼吸;而在强光下效率减低,则是呼吸所供给的ATP不足而必需依靠循环光合磷酸化所致。

In order to test the tactic response of the cotton bollworm, Heliothis ammigera(Hubner), to the odors of its preferred host plant, certain volatile substances known tobe present in the cotton plant such as methanol, trimethylamine and vanillic acid werechosen as olfactory stimulants. It was found that the larvae in the early three instarswere attracted by the vapors of vanillic acid and trimethylamine in various degrees, butmethanol vapor had a repellent effect. These vapors were emitted from aqueous solu-tions...

In order to test the tactic response of the cotton bollworm, Heliothis ammigera(Hubner), to the odors of its preferred host plant, certain volatile substances known tobe present in the cotton plant such as methanol, trimethylamine and vanillic acid werechosen as olfactory stimulants. It was found that the larvae in the early three instarswere attracted by the vapors of vanillic acid and trimethylamine in various degrees, butmethanol vapor had a repellent effect. These vapors were emitted from aqueous solu-tions at the concentrations of 0.006 M 0.02 M and 0.03 M respectively. By using thesugars, free amino acids and vitamins which were shown to be present in the cotton plantas gustatory stimulants and incorporating them separately in the agar-based media, it wasfound that at the concentration of 0.02 M sucrose and fructose had a definite phago-stimulating effect, glucose was less effective, and xylose was indifferent. At low concen-trations, only DL-alanine among the five amino acids tested had some phago-stimulatingeffect, and ascorbic acid at 0.01 M was phago-inhibitive. These results show that thecotton bollworm as a polyphagous species responds differently to the individual com-ponents of the host plant which may act either as attractants or repellents, phago-stimulants or phago-inhibitors. Different species and varieties of cotton plants and some descendants from thehybridization between cotton and some other malvaceous plants such as Hibiscus palus-tris,H. mutabilis, Malva sylvestris and Althaea rosea were used to test the tactic andfeeding responses of the cotton bollworm. It was found that when the larvae had thechance to choose their food, they were more readily attracted to the leaves of Gossypiumhirsutum and certain variety of G. barbadense, but not so readily to some of the hybriddescendants, some of which may even show repulsive properties in the test. In thisrespect different varieties of H. barbadense also had different effects. When there wasno chance to choose their food, the larvae were observed to consume different quantitiesof foliage from different plants in a definite period of time and to become conditionedto the host plants with which they were brought up. Simultaneous chemical analysis showed that the water content as well as the total andprotein nitrogen contents of the cotton leaves gradually decreased as growth proceeded.The total nitrogen content also dropped when the squares developed into flowers, andthe protein content was found to reach the maximum when the squares had attained alength about 2.5 cm. The total and protein nitrogen contents of the bolls dropped asthe latter grew and aged. The total and protein nitrogen contents of the leaves seemedto be the highest as compared with those of the squares and bolls. The quantities ofsoluble and reducing sugars of the young leaves exceeded those of the tender and oldleaves, but the sugar contents of the bolls were found to be much higher than those ofthe leaves. The sugar contents of the squares were relatively low. In spite of these disparities, it was possible to grow the larvae after hatching into maturity separately andsolely on the leaves, squares and bolls of the cotton plants. In these rearing experi-ments, the cumulative quantities of food consumed, the rates of development and mor-tality, and the weights of pupae thus obtained were found to be conspicuously different.It is interesting to note that the larvae during the whole course of development wouldconsume the old leaves to an amount which may double the total quantity of the foodconsumed when the young leaves were offered. When the bolls were used as food thecumulative quantity consumed exceeded several times that when the leaves were used.This difference is presumably attributed to the differences in the water and sugar con-tents of the different organs of the cotton plant, as already shown that sugars usuallywould evoke a strong phago-stimulating effect. The general impression is that the plantorgans which have the higher sugar and water contents usually have a better nutritiveeff

本工作选用棉花不同器官所含有的几种化学成分作为嗅觉和味觉刺激剂,测验棉铃虫对它们的反应;结果表明一至三龄的幼虫对甲醇三甲基胺、香草酸等的趋性不同,四龄幼虫对不同的糖类、氨基酸等的取食反应也各不一。这说明幼虫对食料植物中的个别化学成分有感觉辨识的能力。用不同品种的海岛棉、陆地棉、以及棉花和其它锦葵科植物杂交所产生的后代的叶片来试验棉铃虫对它们的趋性和取食反应,结果表明当有选择的机会时幼虫对陆地棉和一定品种海岛棉有较强的趋性,对某些杂交后代的趋性很弱。在不能选择的条件下棉铃虫在一定时间内对不同种类或品种的棉叶的取食量也不相同,并对原来的食料植物可形成条件化。 曾对棉花不同器官的含水量、含氮物质和糖类进行了测定,同时分别用叶、蕾和铃将新孵化的幼虫饲养到老熟。幼虫取食不同器官时的累积食量、发育速度、死亡率,和变成的蛹的重量均有明显的差别。当以大叶为食时幼虫的总食量超过以嫩叶为食时的一倍以上;以铃为食时总食量可为以嫩叶为食时的数倍。这种差异可能是因铃中水分和含糖量较高,对幼虫的取食发生强烈的助长作用所造成的。因此,同株植物上含糖和含水缺多的器官对棉铃虫似乎有较好的营养效应,而这种效应可能是通过糖类等的味觉刺激来增加取食...

本工作选用棉花不同器官所含有的几种化学成分作为嗅觉和味觉刺激剂,测验棉铃虫对它们的反应;结果表明一至三龄的幼虫对甲醇三甲基胺、香草酸等的趋性不同,四龄幼虫对不同的糖类、氨基酸等的取食反应也各不一。这说明幼虫对食料植物中的个别化学成分有感觉辨识的能力。用不同品种的海岛棉、陆地棉、以及棉花和其它锦葵科植物杂交所产生的后代的叶片来试验棉铃虫对它们的趋性和取食反应,结果表明当有选择的机会时幼虫对陆地棉和一定品种海岛棉有较强的趋性,对某些杂交后代的趋性很弱。在不能选择的条件下棉铃虫在一定时间内对不同种类或品种的棉叶的取食量也不相同,并对原来的食料植物可形成条件化。 曾对棉花不同器官的含水量、含氮物质和糖类进行了测定,同时分别用叶、蕾和铃将新孵化的幼虫饲养到老熟。幼虫取食不同器官时的累积食量、发育速度、死亡率,和变成的蛹的重量均有明显的差别。当以大叶为食时幼虫的总食量超过以嫩叶为食时的一倍以上;以铃为食时总食量可为以嫩叶为食时的数倍。这种差异可能是因铃中水分和含糖量较高,对幼虫的取食发生强烈的助长作用所造成的。因此,同株植物上含糖和含水缺多的器官对棉铃虫似乎有较好的营养效应,而这种效应可能是通过糖类等的味觉刺激来增加取食量所造成。

 
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