对...必需

Copper is one of the essential microelements for plants. But in recent years, the abuse of copper bactericide and industrial pollution has led to the increase of copper content in environment such as in soil.

铜是一种高等植物生长发育过程中必需的重要微量营养元素，是许多胞内酶所必需的组分或辅酶，它参与很多生理代谢过程，对作物的发育、品质、产量等有重要的影响。

To better understand the roles of LsrA protein in nodulation, a series of analyses of nodules using scanning electron microscopy, genetic and biochemical approaches have been carried out. Our analyses suggest that the lsrA1 nodules contain bacteroids in the invasion and establishing zone only. The lsrA gene expression is active early in the invasion zone and activated later than bacA genes. The lost of LsrA protein dramatically reduced the expression of nifA and fixK, and completely blocked the expression of the nifH gene for nitrogenase. LsrA protein functions early in the bacteroid development and it is essential for the development nitrogen fixing bacteroids.

前期的工作中，苜蓿中华根瘤菌Rm1021中90个候选LysR基因已经被定向插入突变，并筛选在自生生长时期、共生生长时期的表型，以期寻找更多在自生状态或共生固氮中有功能的LysR转录因子。1 针对前期鉴定出的共生固氮必需的lsrA基因，我们应用了一系列扫描电子显微镜技术、生物化学、分子遗传学等方法，发现lsrA基因主要在根瘤侵染区开始表达，表达时序也在侵染阶段左右，但晚于bacA基因表达；LsrA蛋白缺失后根瘤固氮区中缺乏具有固氮能力的类菌体，nifA和fixK基因的转录水平降低，nifH基因的转录被完全阻断，因此LsrA蛋白为根瘤发育所必需，是新的根瘤发育信号传导途径成员。2 通过表型筛选我们鉴定了苜蓿中华根瘤菌的oxyR基因，并研究了它的调节特性。oxyR突变后，苜蓿中华根瘤菌对过氧化氢敏感性提高，适应性降低。

The playback method includes a first step of outputting stereo audio signals using the monaural audio signal if the necessary stereo process information is not supplied; a second step of starting updating stereo variables within filters, and outputting the stereo audio signals using the monaural audio signal until all the state variables are updated, if the necessary stereo process information is supplied; and a third step of performing the stereo process based on stereo process information acquired by the necessary stereo process information, on the monaural audio signal to generate and output stereo audio signals, if all the state variables within the filters are updated.

该再生方法包括：第一步骤，如果没有提供立体声处理必需信息，则输出使用了非立体声音频信号的立体声音频信号；第二步骤，如果提供了立体声处理必需信息，则开始更新滤波器内的状态变量，并输出使用了非立体声音频信号的立体声音频信号，直到更新完所有的状态变量；以及第三步骤，如果更新完滤波器内的所述状态变量，则对非立体声音频信号执行基于通过立体声处理必需信息获取的立体声处理信息的立体声处理，并生成并输出立体声音频信号。

The results showed that the crude protein content,the eighteen essential amino acids and the twelve essential amino acids in the powder of tetraploidy black locust for fodder leaves were highly at the four stages,and along with the time process,they were all descending gradually.Moreover,their essential amino acid score were also highly and their amino acid were balanceable.And their essential amino acid index of cattle,pig,chicken,duck,goose,fish,prawn and sheep were higher than 0.86,therefore they can be the excellent fodder of these animals.

结果表明，饲料型四倍体刺槐叶粉4个时期的粗蛋白1、8种氨基酸总量和12种必需氨基酸含量均较高，且呈现随时间的推移而逐渐下降的趋势；其必需氨基酸分均较高，氨基酸组成较平衡；对牛、猪、鸡、鸭、鹅、草鱼、对虾和羊8种动物的必需氨基酸指数4个时期之间无差异，均大于0.86，可作为这些动物的优良植物饲料蛋白源；在7月中下旬其生物量和营养达到了最佳结合点，适宜采摘或刈割。

Your transcendence is necessary beloved, necessary to the ascension of Earth.

你的超越是必需的，至爱的人类，对地球的提升是必需的。

The former is necessary for equilibrium-controlled synthesis of peptide bonds while the latter is necessary for kinetically controlled synthesis of peptide bonds.

酰胺酶活性起水解或合成肽键的作用，因而对平衡控制的肽键合成是必需的；酯酶活性起转移酰基的作用，因而对动力学控制的肽键合成是必需的。

The content of essential amino acid was 57.48%, which was little higher than that of non-essential amino acid. The amino acid with the highest content in vitellin was Glu, its content was 15.26%; while contents of Trp and Met were very low, only 0.50% and 0.11%, respectively.

对卵黄蛋白的氨基酸组成和含量分析发现，其必需氨基酸总量占57.48%，略高于非必需氨基酸，其中谷氨酸含量最高，为15.26%；色氨酸和蛋氨酸含量较低，分别为0.50%和0.11%。

With the help of RP-HPLC, the hydrolyzes of corn gluten meal were found to be rich in Pro and basic amino acid, such as Phe and Leu, which can be used as food additives to supply basic amino acid and to lower blood pressure.

利用反相高效液相色谱法对玉米黄粉蛋白酶解产物的氨基酸组成进行了测定，发现酶解产物中含有大量的Phe(Phenylalanine，苯丙氨酸)，Leu(Leucine，亮氨酸)等必需氨基酸和Pro(Proline，脯氨酸)，他们可以添加到食品中来补充必需的氨基酸和降低高血压患者的血压，对综合开发利用这一丰富的农副产品具有重要的意义。

The values of EAAI in rotifer and nauplii of Artemia were all above 90 for different larval stages of Scylla serrata. It was suggested that rotifer and nauplii of Artemia may satisfy the nutritive requirement of larval Scylla serrata for amino acids in diet protein.

对于各期幼体，饵料轮虫和卤虫无节幼体的必需氨基酸指数均大于90，可以认为，轮虫和卤虫无节幼体能够满足锯缘青蟹幼体对饵料中必需氨基酸的营养需求。

And the young sneer at the Oughts and resist the Musts with all their energy.

学生们对&必需&的课业嗤之以鼻，并竭尽全力对抗那些&必须&进行的学习。

Objective To investigate the effects of interleukin-1 β converting enzyme gene on the biologic characteristics of ovarian cancer cells.

目的 探讨白细胞介素-1 β转换酶的表达，对卵巢癌细胞生物学特性的影响。

Campylobacter: This illness is the most commonly identified cause of diarrheal illness in the world.

弯曲：这种病是最常见的原因查明腹泻病，在世界上。