共查询到20条相似文献，搜索用时 31 毫秒
1.
为利用RNAi技术获取抗水稻黑条矮缩病毒(RBSDV)和南方水稻黑条矮缩病毒(SRBSDV)植株,分别针对两种病毒的S6和S10基因构建RNA沉默载体。采用重组PCR方法将RBSDV S6基因片段(R6)和SRBSDVS6基因片段(SR6)进行融合,获得600 bp的R6-SR6融合基因;将RBSDV S10基因片段(R10)和SRBSDV S10基因片段(SR10)进行融合,获得600 bp的R10-SR10融合基因。融合基因以反向重复的方式连入pBS载体,并定向插入到pCAMBIA1301载体上,获取了含有发夹结构的植物表达载体pCAMBIA1301-hp(R6-SR6)和pCAMBIA1301-hp(R10-SR10)。抗RBSDV和SRBSDV RNA沉默载体的构建为利用RNA沉默进行植物抗病毒研究奠定了基础。 相似文献
2.
一种具有对映选择性催化萘普生乙酯水解的多克隆抗体 总被引：1，自引：0，他引：1
研究了一种具有对映选择性催化萘普生乙酯水解的多克隆抗体。先设计并合成消旋膦酸酯Ｐ１，与载体蛋白偶联得到适于动物免疫的抗原体系Ｐ２和Ｐ３，通过适当的分离和离子交换色谱处理，得到一种新的免疫球蛋白（ＩｇＧ）－多克隆抗体。它能加速Ｒ－构型萘普生乙酯水解成为Ｓ－构型，且具有高度专一性，此多克隆抗体为超分子识别。 相似文献
3.
Sequence-specific peptide cleavage catalyzed by an antibody 总被引：6，自引：0，他引：6
Monoclonal antibodies have been induced that are capable of catalyzing specific hydrolysis of the Gly-Phe bond of peptide substrates at neutral pH with a metal complex cofactor. The antibodies were produced by immunizing with a Co(III) triethylenetetramine (trien)-peptide hapten. These antibodies as a group are capable of binding trien complexes of not only Co(III) but also of numerous other metals. Six peptides were examined as possible substrates with the antibodies and various metal complexes. Two of these peptides were cleaved by several of the antibodies. One antibody was studied in detail, and cleavage was observed for the substrates with the trien complexes of Zn(II), Ga(III), Fe(III), In(III), Cu(II), Ni(II), Lu(III), Mg(II), or Mn(II) as cofactors. A turnover number of 6 x 10(-4) per second was observed for these substrates. These results demonstrate the feasibility of the use of cofactor-assisted catalysis in an antibody binding site to accomplish difficult chemical transformations. 相似文献
4.
辣椒雄性不育恢复系的筛选研究 总被引：1，自引：1，他引：0
对辣椒胞质雄性不育系8A与5个自交系组配的30个测交组合进行育性和结籽调查,结果表明,当组合中每个单株的育性为3级和4级,单株结果和果实形状正常,单果种子数多时,该组合为恢复组合,相应父本为恢复系。初步确定S7、S9、S10和S19共4个组合为恢复组合,相应父本R12-3、R12-5、R12-6、R22-2为恢复系。这4个恢复组合果实性状表现较好,符合育种需求;其中以恢复组合S19的折合产量最高,为74 478.0 kg/hm2,较对照品种陇椒2号增产36.7%,其余3个恢复组合均较对照减产。 相似文献
5.
Hypertension in the recently weaned Dahl salt-sensitive rat despite a diet deficient in sodium chloride 总被引：1，自引：0，他引：1
The Dahl rat is used as a model of hypertension that is "sensitive" to dietary salt (sodium chloride, NaCl). When dietary salt is supplemented in the Dahl rat, the arterial blood pressure of the "salt-sensitive" strain (S) becomes much greater than that of the "salt-resistant" strain (R). It has been widely reported that arterial blood pressure of the young Dahl S rat is not greater than that of the young Dahl R rat before dietary salt is supplemented. In the present study, however, mean arterial pressure directly measured in unanesthetized, unrestrained S rats was greater than in R rats, both when they had been recently weaned and for at least 10 weeks thereafter, despite their having been fed a diet frankly deficient in salt. In weanling S rats, the ratio of heart weight to body weight was also significantly greater than that in weanling R rats, suggesting that the greater blood pressure in the S rat causes cardiac hypertrophy. Thus, biologic differences demonstrated between the S rat and the R rat after weaning, including the phenomenon of salt-sensitivity, could be a consequence of, or be dependent on, an already extant difference in arterial blood pressure between the two strains. 相似文献
6.
大恒优质肉鸡早期体重发育规律 总被引：1，自引：0，他引：1
为了探讨家禽生长发育的规律性,选用大恒优质肉鸡第七世代的S06、S01、S05品系公母各50只,测定1~10周龄的体重,并用Logistic、Bertanlanffy、Gompertz模型对其进行生长曲线拟合。结果表明,3种模型都能很好地拟合大恒优质肉鸡体重的生长曲线(R2>0.99)。但综合分析表明,Gompertz曲线对S06♀(R2=0.9981)、S01♂(R2=0.9991)拟合最为合适。Bertanlanffy曲线对S06♂(R2=0.9987)、S01♀(R2=0.9996)、S05♂(R2=0.9996)和S05♀(R2=0.9995)拟合最合适。 相似文献
7.
对分离自肉鸡肠胃的4株芽孢杆菌R1、R2、S1、H1的16S rDNA序列进行PCR扩增并测定其核酸序列,在NCBI中通过Nucleotide BLAST查找其同源序列,应用DNAstar的MegAlign软件中的Jotun Hein、Clustal V 、Clustal W3种方法进行序列差异和同源性分析,分别使用Mega5.0软件中的最大似然法、邻接法、最小进化法、最大简约法构建系统发育树.序列差异和同源性分析结果显示:由Jotun Hein法可知,H1和R2与Bacillus subtilis DSM10同源性最高,达到100％;R1与B.vallismortis DSM11031同源性最高,达到99.7％;H1与B.subtilis DSM10的同源性为99.9％.由Clustal V法可知,H1与R2同源性最高,达到99.6％;R1与S1同源性最高、为98.7％.由Clustal W法可知,H1与R2同源性最高、为99.7％,R1与S1为99.4％.采用4种方法构建的系统发育树基本一致,可以确立4株鸡源芽孢杆菌的分类地位,R1、S1与B.subtilis BPRIST009、B.subtilis LXB3、B.vallismortis DSM11031之间关系最为亲近;R2、H1与B.subtilis CICC10076、B.subtilis DSM10之间关系最为亲近. 相似文献
8.
【目的】完善玉米种质资源对玉米南方锈病的抗性信息,为可持续性抗病育种和玉米生产提供参考依据。【方法】以齐319和黄早四为高抗（HR）和高感（Hs）对照,采用人工辅助接种法对379份玉米种质资源进行抗南方锈病鉴定。【结果】352份国际小麦玉米改良中心（CIMMYT）的玉米白交系中,表现HR（高抗）、R（抗）、MR（中抗）、s（感）、HS（高感）的份数依次为139、104、38、40和31份,所占比率分别为39．49％、29．55％、10．80％、11．36％和8．80％;12份温带玉米自交系中,两份表现为HR或R,10份表现为s或HS;154k）玉米杂交种中,10份表现为R或MR,5份表现为s或HS。【结论】目前广西主推的普通玉米品种大部分对玉米南方锈病有较好的抗性;CIMMYT的玉米白交系中存在丰富的抗锈病资源。 相似文献
9.
采用生物酶法提取林蛙头多糖,应用响应面法对提取工艺进行了优化,分析了提取物对大鼠降血脂的功效。结果表明：林蛙头多糖最佳提取工艺参数为：酶解温度55℃、加酶量2％、林蛙头水溶液质量浓度1∶10 g／mL、酶解时间4．5 h、pH＝10．0,此条件下林蛙头多糖得率最高为4．3％;高脂模型大鼠降血脂试验结果显示,林蛙头多糖能明显降低高脂模型大鼠血清总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL－C）质量浓度,提高血清中高密度脂蛋白胆固醇（ HDL－C）质量浓度,对高脂大鼠具有显著的降血脂作用。 相似文献
10.
Binding of benzo[a]pyrene 7,8-diol-9,10-epoxides to DNA, RNA, and protein of mouse skin occurs with high stereoselectivity 总被引：7，自引：0，他引：7
M Koreeda P D Moore P G Wislocki W Levin H Yagi D M Jerina 《Science (New York, N.Y.)》1978,199(4330):778-781
The formation, stereostructure, and cellular reactions of the 7,8-diol-9,10-epoxide metabolites of the carcinogen benzo[a]pyrene have been examined after topical application of benzo[a]pyrene to the skin of mice. In this known target tissue, polymer adducts from diastereomeric diol epoxides, (+)-(7S, 8R, 9R, 10R) and (+)-(7R, 8S, 9R, 10R), were formed stereospecifically from their corresponding 7,8-dihydrodiols. Both diol epoxides bind with proteins, RNA, and DNA in vivo. For the nucleic acids, binding occurs preferentially at the 2-amino group of guanine in cellular RNA and DNA in vivo. Methods for establishing the structure of the cellular adducts as well as the possible biological implications of their formation are discussed. 相似文献
11.
Location and chemical synthesis of a pre-S gene coded immunodominant epitope of hepatitis B virus 总被引：27，自引：0，他引：27
Immunodominant, disulfide-bond independent epitopes recognized by human antibodies to hepatitis B virus (HBV) are located within the 55-residue amino terminal portion (coded for by the pre-S region of HBV DNA) of minor HBV envelope components larger than the major protein constituents encoded by the S gene. A peptide having the sequence of the first 26 amino acids from the amino terminal methionine was synthesized and elicited antibodies (at dilutions of greater than or equal to 1 to 10(5) ) to the HBV envelope. These antibodies can be utilized for diagnostic tests. The immunogenicity of the peptide was substantially increased by covalent attachment to liposomes. The disulfide bond-independent determinants on sequences coded for by the pre-S gene may be more easily mimicked by peptide analogs than "conformational" determinants on the S-gene product. 相似文献
12.
鸡肝酯酶快速检测氰戊菊酯农药的试验研究 总被引：1，自引：1，他引：0
采用鸡肝酯酶对不同浓度的氰戊菊酯农药进行了催化水解,并通过pH-stat法优化了水解条件.结果表明,在pH 8.0,温度55℃的条件下,酶催化反应速度较大.在该反应条件下,分析了农药浓度(1/x)与酶解反应初速度(1/y)之间的关系,发现在0.05～2.00 mg·L-1农药浓度范围内,两者的关系曲线为y=0.0723... 相似文献
13.
紫茎泽兰化学成分的分离鉴定及抑菌活性测定 总被引：1，自引：0，他引：1
对紫茎泽兰全株进行分离鉴定,得到14个化合物,其化学结构分别确定为:3β-20(29)-烯基-3-羽扇豆醇硬脂酸酯(Ⅰ)、达玛烷-20,24-双烯-3α-乙酸酯(Ⅱ)、十七烷酸甲酯(Ⅲ)、(1S*,6R*,7R*,10R*)-杜松-4-烯-7-醇(Ⅳ)、表木栓醇(Ⅴ)、2-脱氧-2乙酰氧基-9-羰基泽兰酮(Ⅵ)、正二十三烷醇(Ⅶ)、豆甾醇(Ⅷ)、2,2′-(1,4-二萘基)双(苯并恶唑)(Ⅸ)、7-羰基泽兰酮(Ⅹ)、阿魏酸(Ⅺ)、蒲公英甾醇棕榈酸酯(Ⅻ)、(-)-(5S*,6S*,7S*,9R*,10S*)-7-hydroxy-5,7-epidioxycadinan-3-ene-2-one(ⅩⅢ)、邻羟基桂皮酸(ⅩⅣ),其中化合物Ⅰ、Ⅳ、Ⅸ为首次从紫茎泽兰中分离得到。采用孢子萌发法对部分化合物进行了抑菌试验,结果表明化合物Ⅰ对霜疫霉有较好的抑制作用,EC50值为86.9μg/mL。 相似文献
14.
A genetic polymorphism in the renin gene of Dahl rats cosegregates with blood pressure 总被引：13，自引：0，他引：13
Blood pressure is influenced by multiple genetic loci whose identities are largely unknown. A restriction fragment length polymorphism (RFLP) in the renin gene was found between Dahl salt-hypertension-sensitive (S) and Dahl salt-hypertension-resistant (R) rats. In an F2 population derived from crossing S and R rats, the renin RFLP cosegregated with blood pressure. One dose of the S-rat renin allele was associated with an increment in blood pressure of approximately 10 mmHg, and two doses of this allele increased blood pressure approximately 20 mmHg. From this it can be definitively concluded that in the rat the renin gene is, or is closely linked to, one of the genes regulating blood pressure. 相似文献
15.
烤烟烟叶成熟度与香气质量的关系 总被引：51，自引：0，他引：51
以河南产烤烟为试材，研究了烤烟烟叶成熟度与香气质量关系。结果显示：1)烟叶中主要香气成分的含量随烤烟成熟度的提高而增加，如3-甲基-2-乙酰苯酚、香叶基香叶二烯、(1S，2E，4R,6R，7E,11S)-2,7,12-西柏三烯-4，6-二醇、10-异丙基-3，7，13-三甲基-2，6，11，13-十四碳四烯-1-醇、巨豆-4，6(E)。8(E)-三烯酮-3、十四碳酸等，在烟叶充分成熟阶段达到最大值，之后开始缓慢下降；2)烟碱、十六碳酸、(1S、2E、4R、6R、7E、11S)-2,7,12-西柏三烯-4，6，11-三醇、(1S，2E，4R，6R，7E，11S)-8，11-氧撑-2，6,12-西柏三烯-4-醇等香气成分含量则随着成熟度的提高持续增加，最大值出现在过熟阶段；3)2-呋喃甲醛、2-甲基苯甲醛、1-乙基环己烯、1，2-苯二甲酸异丁正丁酯、巨豆-4．6(Z)，8(Z)-三烯酮-3等香气成分含量随着成熟度提高呈稳定下降趋势；4)成熟时烟叶的糖含量高。总氮、烟碱含量适宜，各种化学比值协调，烟叶香气量足，香气质好，杂气、刺激性明显减轻，总体香吃味质量最好，而成熟不够或者过熟的烟叶．其内在质量明显降低。 相似文献
16.
【目的】探索商品化β-葡聚糖酶水解小麦秸秆制备纤维寡糖的最佳条件,为纤维寡糖的工业化生产提供科学依据。【方法】采用浓硫酸和浓盐酸混酸降解微晶纤维素制备纤维寡糖混合物,通过分离纯化得到聚合度为2—5的纤维寡糖单一组分。用所得纤维二糖作为标准品测定小麦秸秆酶解产物中的纤维二糖,并以纤维二糖含量和小麦秸秆转化率为衡量指标,研究酶解反应温度、pH、反应酶底比E/S、反应底物浓度、反应时间对寡糖生成的影响。【结果】采用活性炭柱层析法得到了高纯度的聚合度2-5的纤维寡糖单一组分;当酶解反应温度为50℃、pH为5.5、E/S为0.4、底物浓度为2%、时间10 h时酶解效果最好,小麦秸秆总转化率达到55.57%,纤维二糖得率为148.15 mg•g-1秸秆。【结论】活性炭柱层析可以很好地分离纤维寡糖,得到了聚合度为2—5的纤维寡糖单一组分;酶解小麦秸秆总转化率及纤维二糖得率均提高。 相似文献
17.
Fluorocitrate inhibition of aconitase: relative configuration of inhibitory isomer by x-ray crystallography 总被引：2，自引：0，他引：2
H L Carrell J P Glusker J J Villafranca A S Mildvan R J Dummel E Kun 《Science (New York, N.Y.)》1970,170(965):1412-1414
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. 相似文献
18.
大豆对SMV株系SC10的抗性遗传及抗病基因的定位研究 总被引：1，自引：1，他引：0
【目的】明确大豆对SMV株系SC10的抗性遗传方式以及不同抗源所携带的抗病基因间的等位关系,并对科丰1号所携带的抗SC10基因进行标记定位。【方法】利用抗中国南方大豆产区流行株系SC10的科丰1号、晋大74、大白麻、汾豆56、中作229、徐豆1号、邳县茶豆、Kwanggyo、跃进4号配制部分抗抗杂交组合并与感病品种南农1138-2和8101配制抗感组合,在接种SC10的条件下,调查各组合后代的抗感反应;并利用科丰1号×南农1138-2的F2群体和分离群体分组分析法（BSA）及SSR标记对抗病基因进行标记定位。【结果】科丰1号、晋大74、大白麻、汾豆56、中作229和徐豆1号与感病品种杂交的F1表现抗病,F2呈3抗﹕1感分离比例,F2:3家系呈1抗﹕2分离﹕1感病的分离比率;晋大74×汾豆56、徐豆1号×邳县茶豆的F1表现抗病、F2未发现感病株。科丰1号×Kwanggyo、汾豆56、中作229,晋大74×中作229、Kwanggyo,大白麻×汾豆56、科丰1号和跃进4号×Kwanggyo的F1表现抗病,F2呈15抗﹕1感的分离比例,F2:3家系符合7抗﹕4分离（15抗﹕1感）﹕4分离（3抗﹕1感）﹕1感的分离比例;D1b连锁群上的SSR标记Satt558、Sat_254、Satt634、Gm020580、Gm020584、Gm020562和Gm020546与抗病基因RSC10连锁,遗传距离分别为6.1、2.0、0.9、0.8、2.0、4.6和9.2 cM。【结论】科丰1号、晋大74、大白麻、徐豆1号、汾豆56、中作229各有一个显性基因控制对SC10株系的抗性;晋大74与汾豆56,徐豆1号与邳县茶豆的抗病基因是等位的或紧密连锁的;科丰1号与Kwanggyo、汾豆56、中作229携带的抗SC10株系的基因处于不同位点,晋大74与中作229、Kwanggyo携带的抗SC10株系的基因处于不同位点,大白麻与汾豆56、科丰1号携带的抗SC10株系的基因处于不同位点,跃进4号与Kwanggyo携带的抗SC10株系的基因处于不同位点;科丰1号对SC10株系的抗病基因RSC10位于D1b连锁群。 相似文献
19.
R D Granstein J A Parrish D J McAuliffe C Waltenbaugh M I Greene 《Science (New York, N.Y.)》1984,224(4649):615-617
Long-term exposure of C3H mice to ultraviolet radiation resulted in the formation of suppressor T cells that recognize ultraviolet radiation-induced regressor skin cancers as a class before the appearance of overt tumors. Administration of monoclonal antibodies to the product of the I-Jk subregion of the major histocompatibility complex or low doses of cyclophosphamide in vivo inhibited the development or activity of these cells. This activity of the monoclonal antibody was eliminated by adsorption on B10.BR (I-Jk) but not B10.D2 (I-Jd) splenocytes. These findings provide evidence that elements expressing the I-J determinant are important in regulating the host response prior to the overt development of ultraviolet radiation-induced skin cancers and suggest novel therapeutic approaches to malignancies or other diseases involving suppressor T cells in their pathogenesis. 相似文献
20.
云南西盟蔗区发现检疫性病害甘蔗白叶病 总被引：1，自引：1，他引：0
研究旨在明确2018年在云南西盟蔗区发现的甘蔗病害是否为植原体引起的甘蔗白叶病。使用植原体16S rRNA基因序列通用引物P1/P7和R16F2n/R16R2对10份采自云南西盟蔗区的疑似甘蔗白叶病样品进行巢氏PCR检测,并将巢氏PCR 产物进行克隆测序和序列分析。巢氏PCR结果表明,所有10份样品均能扩增得到1240bp左右的片段。测序结果表明所有获得的10条16S rRNA基因序列大小均为1247bp,序列间的核苷酸一致性为100%。BLASTN分析表明从病株扩增到的所有核苷酸序列与先前云南临沧甘蔗白叶病植原体分离物LC7和LC9的16S rRNA基因序列(Genbank登陆号：KR020691和KR020692)的核苷酸序列一致性为100%。虚拟RFLP分析表明西盟分离物的16S rRNA基因序列的酶切图谱与16SrXI-B亚组植原体相同。本研究结果表明云南西盟蔗区发现的甘蔗病害为16SrXI-B亚组植原体引起的甘蔗白叶病。 相似文献