抗旱性不同的两个大豆品种对外源H2O2的响应

两个品种的大豆叶圆片经１０＾－４ｍｏｌ／Ｌ和１０＾－３ｍｏｌ／Ｌ的Ｈ２Ｏ２处理１２ｈ后,超氧化岐化酶（ＳＯＤ）、过氧化氢酶（ＣＡＴ）与谷胱甘肽还原酶（ＧＲ）活性明显增加,但１０＾－２ｍｏｌ／Ｌ的Ｈ２Ｏ２处理却使这些酶活性降低。抗旱性较强的大豆品种小粒豆１号较抗旱性较弱的鲁豆４号能维持较高的叶绿素含量和较高的ＳＯＤ、ＣＡＴ及ＧＲ活性,对Ｈ２Ｏ２的抗性较强。５０μｍｏｌ／Ｌ的亚胺环已酮（ＣＨＭ）能消除     

NMR法研究天花粉蛋白TDK肽片段的溶液构象

用ＨＮＭＲ法测定ＴＤＫ肽在Ｈ２Ｏ（ＨＯＤＫ）,５０％六氟丙醇（ＦＰＤＫ）和２ｍｏｌ／ＬＧｕ．ＨＣｌ（ＧＵＤＫ）溶液构象。在ＨＯＤＫ和ＦＰＤＫ中,ＴＤＫ肽的两段序列Ａｓｐ０－Ｉｌｅ４,Ｓｅｒ９－Ｉｌｉ１７分别具有较稳定的α－螺旋含量;而ＧＵＤＫ的ＳＡＬＳ序列仍能检测到有序残存结构。并假设ＳＡＬＳ序列是肽链形成二级结构的原始核心。     

大鼠卵巢绒毛膜促性腺激素受体在CHO中的表达和扩增

本文报道了利用二氢叶酸还原酶放大系统将大鼠ＬＨ／ｈＣＧ受体（记为Ｆ－ｈＣＧＲ）及其胞外肽段（记为Ｔ－ｈＣＧＲ）在中国苍鼠卵巢细胞（ＣＨＯ）中的表达。ＳＤＳ－ＰＡＧＥ分析表明,Ｆ－ｈＣＧＲ为一条蛋白质带,其表观分子量为９２ｋｄ,而Ｔ－ｈＣＧＲ为３５ｋｄ和３７ｋｄ两条带。表达受体对其配基ｈＣＧ表现出高的亲合力,Ｆ－ｈＣＧＲ的解离常数为７×１０－９ｍｏｌ／Ｌ,Ｔ－ｈＣＧＲ为６．４×１０－９ｍｏｌ／Ｌ。表达Ｆ－ｈＣＧＲ的转染ＣＨＯ细胞可结合１２５Ｉ－ｈＣＧ,而表达Ｔ－ｈＣＧＢ者不结合１２５Ｉ－ｈＣＧ。这提示Ｆ－ｈＣＧＲ主要存在于细胞质膜表面上。表达Ｆ－ｈＣＧＲ的转染ＣＨＯ细胞能刺激。ｃＡＭＰ的形成,而表达Ｔ－ｈＣＧＲ者不能刺激ｃＡＭＰ形成。免疫荧光定位结果表明,Ｔ－ｈＣＧＲ主要分布于质膜的细胞质侧以及胞内其他一些细胞器膜上。用免疫亲和层析可以得到纯化的Ｔ－ｈＣＧＲ。     

HMR法研究天花粉蛋白TDK肽片段的溶液构象

用１ＨＮＭＲ法测定ＴＤＫ肽在Ｈ２Ｏ（ＨＯＤＫ）,５０％六氟丙醇（ＦＰＤＫ）和２ｍｏｌ／ＬＧｕ·ＨＣｌ（ＧＵＤＫ）中的溶液构象。在ＨＯＤＫ和ＦＰＤＫ中,ＴＤＫ肽的两段序列Ａｓｐ０～Ｉｌｅ４,Ｓｅｒ９～Ｉｌｅ１７分别具有较稳定的α－螺旋含量;而ＧＵＤＫ的ＳＡＬＳ序列仍能检测到有序残存结构。并假设ＳＡＬＳ序列是肽链形成二级结构的原始核心。     

铝对玉米生长和硝酸还原酶活性的影响

测定了生长在Ａｌ２（ＳＯ４）３１００μｍｏｌ／Ｌ氮素营养液中的两个玉米品种（ＳＣ７０４和ＶＡ３５的根系和叶片）的ＮＡＤＨ－硝酸还原酶（ＥＣ１．６．６．１）和ＮＡＤ（Ｐ）Ｈ－硝酸还原酶（ＥＣ１．６．６．２）活性。     

南方鲇碱性磷酸酶的分离纯化及部分性质的研究

用正丁醇抽提,硫酸铵分级沉淀,ＤＥＡＥ－纤维素和ＳｅｐｈａｃｒｙｌＳ－２００柱层析,从南方鲇（Ｓｉｌｕｒｕｓ　ｍｅｒｉｄｉｏｎａｌｉｓ　Ｃｈｅｎ）肠粘膜中提取出碱性磷酸酶（ＡＫＰ）。提纯倍数为３９．５０倍,比活为６８．３５μ／ｍｇ蛋白,提取酶液经ＰＡＧＥ和ＳＤＳ－ＰＡＧＥ只呈现一条区带。该酶的分子量为１３２１４０,Ｎ末端氨基酸为门冬氨酸,最适ｐＨ为１０．１０,７．５＞ｐＨ＞１１．５时不稳定,最适温度为４０℃左右,对热不很稳定,以磷酸苯二钠为底物其Ｋ_ｍ值为１．７２×１０~（－３）ｍｏｌ／Ｌ。Ｍｇ~（２＋）、Ｍｎ~（２＋）为该酶的激活剂,ＫＨ_２ＰＯ_４、Ｌ－ＣｙＳ、ＭＥ、ＤＦＰ、ＥＤＴＡ－Ｎａ_２为抑制剂。选用ＫＨ_２ＰＯ_４和ＤＦＰ作抑制类型的判断,结果表明,ＫＨ_２ＰＯ_４属竞争性掏剂,其抑制常数为２．３ｍｍｏｌ／Ｌ;ＤＦＰ为非竞争性抑制剂,抑制常数为１．０５ｍｍｏｌ／Ｌ。     

黑龙江铜木蚜蝇雌性的描述

黑龙江铜木蚜蝇雌性的描述ＤＥＳＣＲＩＰＴＩＯＮＯＦＴＨＥＦＥＭＡＬＥＣＨＡＬＣＯＳＹＲＰＨＵＳ（ＸＹＬＯＴＯＭＩＭＡ）ＡＭＵＲＥＮＳＩＳ（ＳＴＡＣＫＥＬＢＥＲＧ）（ＤＩＰＴＥＲＡ：ＳＹＲＰＨＩＤＡＥ）￥ＨＥＪｉｌｏｎｇ;ＣＨＵＸｉｐｉｎｇ（Ｄｅｐａｒ...     

一氧化氮抑制内皮素促血管平滑肌细胞增殖作用的信号转导途径

培养的家兔胸主动脉血管平滑肌细胞（ＶＳＭＣ）分别以内皮素（ＥＴ－１）、一氧化氮（ＮＯ）前体Ｌ－Ａｒｇ和ＮＯ供体ＳＩＮ－１刺激,或用ＥＴ－１＋Ｌ－Ａｒｇ、ＥＴ－１＋ＳＩＮ－１联合刺激,测ＶＳＭＣ＾３Ｈ－ＴｄＲ掺入、丝裂素活化蛋白激酶（ＭＡＰＫ）活性及蛋白激酶Ｃ（ＰＫＣ）活性的改变,以研究ＮＯ抑制ＥＴ－１促ＶＳＭＣ增殖作用的信号转导途径。结果表明：（１）ＥＴ－１ １０＾－８ｍｏｌ／Ｌ单独刺激,＾３Ｈ－     

抗寒剂CR－4在克服我县水稻低温烂秧中的作用

抗寒剂ＣＲ－４在克服我县水稻低温烂秧中的作用赵玉华（甘肃高台县农业局７３４３００）ＥＦＦＥＣＴＯＦＴＨＥＰＬＡＮＴＣＯＬＤ－ＲＥＳＩＳＴＥＲＯＮＯＶＥＲＣＯ－ＭＩＮＧＲＩＣＥＳＥＥＤＬＩＮＧＤＥＣＡＹＩＮＬＯＷＴＥＭＰＥＲＡＴＵＲＥＳＴＲＥＳＳＩＮＯ...     

盐度和CO2倍增环境下碱蓬幼苗呼吸酶活性的变化

研究了生长在正常大气ＣＯ２和ＣＯ２倍增环境中的盐生植物碱蓬（Ｓｕａｅｄａｓａｌｓａ）幼苗呼吸酶活性对ＫＣｌ和ＮａＣｌ的反应．结果表明,在ＣＯ２倍增（７００μｌ·Ｌ－１）和正常大气ＣＯ２（３５０μｌ·Ｌ－１）下,３００ｍｍｏｌ·Ｌ－１ＫＣｌ和ＮａＣｌ均能抑制琥珀酸脱氢酶（ＳＤＨ）和苹果酸脱氢酶（ＭＤＨ）活性,而异柠檬酸脱氢酶（ＩＤＨ）活性为ＮａＣｌ抑制、ＫＣｌ促进;ＮａＣｌ和ＫＣｌ明显抑制细胞色素氧化酶（ＣＯ）和光呼吸中乙醇酸氧化酶（ＧＯ）、羟基丙酮酸还原酶（ＨＰＲ）活性;并指出在ＫＣｌ胁迫下,ＣＯ２使三羧酸循环（ＴＣＡＣ）的运行变慢,ＮａＣｌ胁迫下使其加快,ＴＣＡＣ运行限速步骤与ＭＤＨ无关,ＣＯ为盐对呼吸代谢影响的重要位点．另外,Ｋ＋、Ｎａ＋对蛋白表达的影响有差异,ＣＯ２可使盐胁迫下的碱蓬幼苗蛋白表达降低．     

BCL2-CISD2

CISD2, an ER BCL2-associated autophagy regulator also known as NAF-1, is responsible for the human degenerative disorder Wolfram Syndrome 2. In order to interrogate the physiological role of CISD2 we generated and characterized the Cisd2 gene deletion in mice. Cisd2 null mice manifest significant degeneration in skeletal muscle tissues, which is accompanied with augmented autophagy, dysregulated Ca²⁺ homeostasis and elongated mitochondria. Our findings describe a novel role for BCL2-CISD2 in the homeostatic maintenance of skeletal muscle. It remains to be elucidated how and if the antagonism of the BECN1 autophagy-initiating complex and modulation of ER Ca²⁺ homeostasis by BCL2-CISD2 are interconnected.     

Synthesis and physicochemical properties of 2'-deoxy-2',2'-difluoro-beta-D-ribofuranosyl and 2'-deoxy-2',2'-difluoro-alpha-D-ribofuranosyl oligonucleotides

We present procedures for nucleoside and oligonucleotide synthesis, binding affinity (Tm) and structural analysis (CD spectra) of 2'-deoxy-2',2'-difluoro-alpha-D-ribofuranosyl and 2'-deoxy-2',2'-difluoro-beta-D-ribofuranosyl oligothymidylates. Possible reasons for the thermal instability of duplexes formed between these compounds and RNA or DNA targets are discussed.     

Synthesis of [11-2H2], [8-2H2], [7-2H2], [6-2H2], [5-2H2], [4-2H2] and [3-2H2] cis-9-octadecenoates

Deuterated oleates have been synthesized by semihydrogenation of acetylenic intermediates. [11-²H₂]Oleate was prepared by two-carbon chain extension of the C₁₆ alcohol obtained from [1-²H₂]octyl bromide and 7-octyn-1-ol. [8-²H₂] and [7-²H₂]oleates were both prepared from dimethyl suberate, tetradeutero intermediate C₁₆ alcohols were synthesized from [1,8-²H₄] and [2,7-²H₄]octane diols by monobromination, conversion to deuterated 9-decyn-1-ols and reaction with octyl bromide. Oxidation gave [8-²H₂]-9-octadecynoate and [2,7-²H₂]-9-octadecynoate, after semihydrogenation of the latter, deuterons at C-2 were removed by exchange with aqueous alkali. [6-²H₂] and [5-²H₂]oleates were obtained from methyl 5-tetradecynoate, semihydrogenation, deuterium exchange at C-2 and two malonate extensions gave [6-²H₂]oleate; reduction with lithium aluminum deuteride, two malonate extensions and semihydrogenation gave the [5-²H₂] ester. [4-²H₂] and [3-²H₂]oleates were both obtained from methyl 7-cis-hexadecenoate, exchange of the α protons and chain extension gave the [4-²H₂] ester and reduction with lithium aluminum deuteride and chain extension gave the [3-²H₂] ester.     

Stereospecific 2'-amination and 2'-chlorination of adenosine by Actinomadura in the biosynthesis of 2'-amino-2'-deoxyadenosine and 2'-chloro-2'-deoxycoformycin

2'-Amino-2'-deoxyadenosine and 2'-chloro-2'-deoxycoformycin (2'-CldCF) are two nucleoside antibiotics produced by Actinomadura. The biosynthesis of these two nucleoside antibiotics has been studied by the addition of [U-14C]adenosine with or without unlabeled adenine to cultures of Actinomadura. By this experimental approach, it is possible to demonstrate that adenosine is the direct precursor for the biosynthesis of 2'-amino-2'-deoxyadenosine and 2'-CldCF. These conclusions are based on the observation that the percentage distribution of 14C in the aglyconic and pentofuranosyl moieties of 2'-amino-2'-deoxyadenosine and 2'-CldCF were similar to the distribution of 14C in the adenine and ribosyl moieties of the [U-14C]adenosine (i.e., 48:52) added to cultures of Actinomadura. Experimentally, the percentage distribution of 14C in the (i) adenine:2-amino-2-deoxy-beta-D-ribofuranose of 2'-amino-2'-deoxyadenosine is 51:49; (ii) 8-(R)-3,6,7,8-tetrahydroimidazo[4,5-d]-[1,3-diazepin-8-o1]:2 -chloro-2- beta-D-ribofuranose of 2'-CldCF is 45:55; and (iii) adenine:ribose of the adenosine isolated from the RNA of Actinomadura is 42:58. Further proof that adenosine is the direct precursor for the biosynthesis 2'-amino-2'-deoxyadenosine and 2'-CldCF was demonstrated by the addition of 75 mumol of unlabeled adenine together with [U-14C]adenosine to nucleoside-producing cultures of Actinomadura. The percentage distribution of 14C in the aglycon and the sugar moieties of 2'-amino-2'-deoxyadenosine and 2'-CldCF were 46:54 and 47:53, respectively; the percentage distribution of 14C in the adenine and ribose moieties of the adenosine isolated from the RNA of Actinomadura was 51:49. These data show that the hydroxyl on C-2' of the ribosyl moiety of adenosine undergoes a replacement by a 2'-amino or a 2'-chloro group to form 2'-amino-2'-deoxyadenosine or 2'-CldCF with retention of stereconfiguration at C-2'. Finally, Actinomadura can utilize inorganic chloride from the medium as demonstrated by the isolation of [36Cl]2'-CldCF following the addition of [36Cl]chloride to the culture medium. Mechanisms for the regioselective modification of the C-2' hydroxyl group and stereospecific insertion of the amino and chloro groups are discussed.     

A concise synthesis of 4-nitrophenyl 2-azido-2-deoxy- and 2-acetamido-2-deoxy-D-mannopyranosides

4-nitrophenyl 3,4,6-tri-O-acetyl-2-azido-2-deoxy-alpha- and beta-D-mannopyranosides were prepared from methyl 4,6-O-benzylidene-alpha-D-glucopyranoside and 1,3,4,6-tetra-O-acetyl-alpha-D-glucopyranose, respectively. Chemoselective reduction of both azides with hydrogen sulfide readily afforded 4-nitrophenyl 2-acetamido-4,6-di-O-acetyl-2-deoxy-alpha-D- and -beta-D-mannopyranosides in higher yields than reduction with triphenylphosphine or a polymer-supported triarylphosphine. Subsequent de-O-acetylation yielded 4-nitrophenyl 2-acetamido-2-deoxy-alpha-D-mannopyranoside and 4-nitrophenyl 2-acetamido-2-deoxy-beta-D-mannopyranoside in 20% and 44% overall yields, respectively.     

Stereospecific formation of alpha-hydroxycarboxylato oxo peroxo complexes of vanadium(V). Crystal structure of (NBu4)2[V2O2(O2)2(L-lact)2] x 2H2O and (NBu4)2[V2O2(O2)2(D-lact)(L-lact)] x 2H2O

An overview of structurally characterized alpha-hydroxycarboxylatodioxo- and alpha-hydroxycarboxylatooxoperoxovanadates(V) is presented and the geometric parameters of the V2O2 bridging core are discussed. The first case of a stereospecific formation of oxoperoxovanadates(V) is reported: The crystal structures of the isomeric compounds (NBu4)2[V2O2(O2)2(L-lact)2] x 2H2O and (NBu4)2[V2O2(O2)2(D-lact)(L-lact)] x 2H2O (lact = C3H4O3(2-), the anion of the lactic acid) differ mainly in the arrangement of the V2O2 core and in mutual orientation of the V=O bonds. The complexes with achiral ligands adopt the same structural type as the complexes formed from a racemic mixture of a chiral ligand, while the structure obtained using an enantiopure L,L-hydroxycarboxylate is different.     

Convenient synthesis of 2'-deoxy-2-fluoroadenosine from 2-fluoroadenine

A convenient synthesis of 2'-deoxy-2-fluoroadenosine from commercially available 2-fluoroadenine is described. The coupling reaction of silylated 2-fluoroadenine with phenyl 3,5-bis[O-(t-butyldimethylsilyl)]-2-deoxy-1-thio-D-erythro-pentofuranoside gave the corresponding 2-fluoro-2'-deoxyadenosine derivative (alpha/beta = 1:1) in good yield. The alpha- and beta-anomers were separated by chromatography, and then desilylated to give compounds 1a and 1b.