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1.
本研究克隆了萤光假单胞菌ＡＳ１．５５（Ｐｓｅｕｄｏｍｏｎａｓ ｆｌｕｏｒｅｓｃｅｎｓＡＳ１．５５）的亮氨酸基因（ｌｅｕ＾＋）ＥｃｏＲＩ片段（－６．６ｋｂ）,并获得含有该片段的重组质粒ｐＢＲ３２２－ＬＥＵ。从ｐＢＲ３２２－ＬＥＵ质粒中分离出ｌｅｕ＾＋ＥｃｏＲＩ片段,将其插入到ｎｉｆＡ质ｐＭＣ７１Ａ的ＥｃｏＲⅠ位点使氯霉素抗性基因失活,从而构建了不带抗药性基因ｎｉｆＡ质粒ｐＭＣ７１Ａ－ＬＥＵ。 相似文献
2.
固氮粪产碱菌胞外多糖的理化特性分析 总被引：1，自引：0，他引：1
ＥＰＳ结构分析表明，ＥＰＳ突变株及工程菌株的糖骨架结构与野生型菌株相比有差异，尤其是ｎｔｒＣ－ｎｉｆＡ基因结合子Ａ１５３２的糖骨架结构明显不同于其它菌株，各个菌株之间，其侧链基因均稍有改变。ＥＴＩＲ证实，各个菌株ＥＰＳ中蛋白构象存在差异，ＥＰＳ中均有丰富的β折叠构象。ＥＰＳ丰富型突变株中无规卷曲构象所占比例较大，而野生型菌株中ＥＰＳ则没有无规卷曲构象。 相似文献
3.
采用电子自旋共振技术（ＥＳＲ），以马来酰亚胺自旋标记粪产碱菌野生型（Ａ１５０１）、胞外多糖突变株（ｅｘｏ＾－和ｅｘｏ＾＋＋）及工程菌（ｎｉｆ某Ａ和ｎｔｒＣ－ｎｉｆＡ重组子），监测由粪产碱菌表面多肽及些膜蛋白构象变化引起的ＥＳＲ波谱的变化。结果表明，粪产碱菌野生型菌株细胞表面特性显著不同于胞外多糖突变株及工程菌，根系粘质及ＮＨ４＾＋都能引起粪产碱菌表面蛋白的构象变化，标记后菌体ＥＳＲ参数τｃ的变化与 相似文献
4.
应用Ａ．ｂｒａｓｉｌｅｎｓｅ ｓｐ７的ｅｘｏＣ基因为探针，发现Ａ．ｆａｅｃａｌｉｓ Ａ１５０１具有与Ａ．ｂｒａｓｉｌｅｎｓｅ Ｓｐ７ ｅｘｏＣ基因同源的基因。Ａ．ｂｒａｓｉｌｅｎｓｅ ｅｘｏＣ基因能恢复Ａ．ｆａｅｃａｌｉｓ ＥＰＳ缺陷型（ＥＰＳ＾－）突变，表明粪产碱菌ＥＰＳ的产量为ｅｘｏＣ基因产物所调控。本工作已获得类似Ａ．ｂｒａｓｉｌｅｎｓｅ Ｓｐ７的ｅｘｏＣ－ｌｉｋｅ基因的克隆 相似文献
5.
黄瓜同种异体嫁接组合形成过程中特异蛋白质的产生 总被引：12，自引：0，他引：12
用ＰＡＧ等电聚焦、ＳＤＳ－ＰＡＧＥ梯度电泳和双向电泳分析了黄瓜同种异体嫁接组合不同发育时期的全蛋白变化。结果表明：与愈伤处理比较，嫁接后第２天到第１０天嫁接组合的不同发育时期，稳定地出现三种新合成的特异蛋白质；通过分子量（ＭＷ）和等电点（ｐＩ）的分析表明这三种特异蛋白质的分子量：等电点分别为：１７．６ｋＤ：４．８５，１５．２ｋＤ：６．２６，２０．６ｋＤ：７．６。最后，对高等植物的嫁接亲和性机理问题 相似文献
6.
应用遗传工程技术分别将含有ｎｉｆＡ＾ｃＤＮＡ片段的质粒及含有Ｔｎ５：：ｎｉｆＡ的广泛宿主自杀性质粒ｐＳＺ３６转入了三个联合固氮菌，即粪产碱菌，阴沟肠杆菌及催娩克氏菌中；把Ｔｎ５：：ｎｉｆＡ－ｎｔｒＣ转入了粪产碱菌野生型菌株Ａ１５０１。这些转化结合子在高铵下表现出固氮活性，并能集聚在水稻根表，而野生型菌在相同条件下远离水稻根表。这些菌株的田间释放实验在严格控制条件下进行，应用＾１５Ｎ稀释技术测定其固 相似文献
7.
石墨炉原子吸收分光光度法测定土壤和植物中的微量镉 总被引：8，自引：0，他引：8
石墨炉原子吸收分光光度法测定土壤和植物中的微量镉刘呜（云南省农业环境保护监测站昆明６５００３４）１仪器ＰＥ－１１００Ｂ型原子吸收分光光度计，ＨＧＡ－７００型石墨炉，ＡＳ－７０型自动进样器，ＥＰＳＯＮＦＸ－８５０型扫印机，镉空心阴极灯，氘灯背景校正器，... 相似文献
8.
为了探讨生长因子（ＥＧＦ，ＰＤＧＦ）对牛卵母细胞体外成熟与早期胚胎体外发育的影响，本研究进行了两个实验。实验１：在卵母细胞体外成熟（ＩＶＭ）中，将卵母细胞平均随机的放入表皮生长因子浓度为０，２．５，２５，５０μｇ／Ｌ的成熟培养液和对照组中。实验２：在早期胚胎体外培养（ＩＶＣ）过程中，将受精卵平均随机分配入５个不同培养液的处理组：（１）ＴＣＭ－１９９＋１０％阉公牛血清（ＳＳ）；（２）ＴＣＭ－１９９＋ＥＧＦ＋ＰＤＧＦ；（３）ＴＣＭ－１９９＋ＥＧＦ；（４）ＴＣＭ－１９９＋ＰＤＧＦ；（５）ＴＣＭ－１９９＋无生长因子、其中ＥＧＦ：５０μｇ／Ｌ，ＰＤＧＦ：０．１μｇ／Ｌ。２，３，４，５组有０．１％ＰＶＡ和０．３％ＢＳＡ，并与颗粒细胞单层协同培养。卵母细胞的体外成熟（ＩＶＭ）、体外受精（ＩＶＦ）和早期胚胎体外培养（ＩＶＣ）的方法与Ｌｕ等（１９８７）报道的相同。结果表明：浓度为５０μｇ／Ｌ的处理组分裂率与对照组无差异（８９．０％，９２．４％，Ｐ＞０．０５），而浓度为０，２．５，２５μｇ／Ｌ的处理组分裂率均显著低于对照组（７８．６％，８２．３％，８４．３％，Ｐ＜０．０５），在囊胚率和第７ｄ一级胚胎率上各组均无差异。ＥＧＦ在体 相似文献
9.
乙肝表面抗原和生长抑素融合基因在杆状病毒中表达 总被引：2，自引：0，他引：2
将乙肝表面抗原（ＨＢｓＡｇ）与生长抑素的融合基因（ＨＢｓＡｇ／ＳＳ）插入杆状病毒转移载体质粒ｐＶＬ１３９３，构成重组转移质粒ｐＶＬ１３９１ＨＳ。经Ｓｏｕｔｈｅｒｎ杂质证实ＨＢｓＡｇ／ＳＳ已插入ＰＶＬ１３９３。借助磷酸钙沉淀法，将ＣｓＣｌ超速离心纯化的重组转移质粒和苜蓿丫纹夜蛾核型多角体病毒（ＡｃＮＰＶ）共转染Ｓｆ９细胞，用荧光空班和酶联免疫测定法（ＥＬＩＳＡ），筛选到重组病毒ＡｃＮＰＶＨＳ。提取感 相似文献
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11.
粪产碱菌耐铵工程菌与水稻联合共生固氮作用 总被引：8，自引：1，他引：7
粪产碱菌（ Ａａｅｃａｌｉｓｆａｅｃａｌｉｓ） 在ＬＷ 培养基下能产生植物激素ＩＡＡ。盆栽结果表明,接种Ａ．ｆａｅｃａｌｉｓ 显著提高了水稻的生长,接种Ａ１５０１ 和Ａ１５１３ 的水稻稻谷产量分别比未接种提高了８５％ 和１０３ ％ ,用１５ Ｎ 同位素稀释法估测水稻地上部总氮中来源联合固氮的百分率达９００ ％ 和１１５ ％ ,其结果与水稻地上部（ 茎叶及稻谷） 总氮量的增加幅度（８６ ％ 和１１６ ％ ）基本一致。研究还表明Ａ１５１３ 耐铵工程菌的产ＩＡＡ作用以及对水稻的生长和产量、联合固氮作用均优于原始菌株Ａ１５０１ 。 相似文献
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13.
The aim of this study was to isolate high‐molecular‐weight (HMW) gliadins from wheat flour and to characterize the protein components that contribute to HMW gliadins. Wheat flour Akteur was extracted with a modified Osborne procedure, and the fraction soluble in 60% ethanol (total gliadins) was separated by gel‐permeation HPLC, yielding three fractions, GP1–GP3. GP1 (21.5%) consisted of oligomeric HMW gliadins, GP2 (15.2%) of ω5‐gliadins, and GP3 (63.3%) of ω1,2‐, α‐, and γ‐gliadins. Two‐dimensional SDS‐PAGE of HMW gliadins showed that interchain disulfide bonds were present in HMW gliadins. The molecular mass distribution of HMW gliadins determined by gel‐permeation HPLC was in a range from 66,000 to 680,000 with an average degree of polymerization of 13. Reduced HMW gliadins were further separated by preparative reversed‐phase HPLC into four subfractions (RP1, RP2, RP3, and RP4), which were characterized by SDS‐PAGE and semiquantitative N‐terminal sequencing. HMW gliadins of the wheat flour Akteur contained all types of gluten proteins: 48% low‐molecular‐weight glutenin subunits, 18% γ‐gliadins, 13% α‐gliadins, 9% ω1,2‐gliadins, 8% HMW glutenin subunits, and 4% ω5‐gliadins. We postulate that the existence of HMW gliadins can be explained by the presence of terminators, which interrupt the polymerization of glutenin subunits during biosynthesis and lead to polymers of limited size (oligomers) that are still soluble in aqueous ethanol. 相似文献
14.
Salazar N Ruas-Madiedo P Prieto A Calle LP de Los Reyes-Gavilán CG 《Journal of agricultural and food chemistry》2012,60(4):1028-1035
Bifidobacteria are natural members of the human intestinal microbiota and some strains are being used as probiotics. Adaptation to bile can allow them to increase survival in gastrointestinal conditions, thus improving their viability. Bifidobacterium longum NB667 and the cholate-resistant strain B. longum IPLA B667dCo produced exopolysaccharides (EPS) that were partially characterized. Analysis by size exclusion chromatography-multiangle laser light scattering indicated that the EPS crude fractions of both strains contained two polymer peaks of different molar mass. On the basis of chromatographic techniques both peaks appeared to be heteropolysaccharides. The smaller peak was mainly composed of glucose, galactose and rhamnose whose molar ratios and linkage types showed slight variations between the EPS fractions of both strains. The bigger peak consisted of glucose and galactose; the monosaccharide composition was identical in the EPS fractions of the two microorganisms, but their infrared spectra presented some differences regarding compounds other than carbohydrates that seem to be associated to the polymer. Differences in the composition of EPS fractions did not affect the capability of crude EPS from B. longum to be fermented by the human intestinal microbiota in fecal batch cultures. 相似文献
15.
Nakamura H 《Journal of agricultural and food chemistry》1999,47(12):5273-5277
Seed storage proteins of Japanese wheat (Triticum aestivum) varieties were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to identify the alleles for complex gene loci, Glu-A1, Glu-B1, and Glu-D1, which code for high molecular weight (HMW) subunits of glutenin in Japanese hexaploid wheat varieties. These were identified by comparison of subunit mobility with those previously found in hexaploid wheat. Twenty-four different, major glutenin HMW subunits were identified, and each variety contained three to five subunits. Seventeen different glutenin subunit patterns were observed for 14 alleles in Japanese varieties. A catalog of alleles for the complex gene loci, Glu-A1, Glu-B1, and Glu-D1, that code for HMW subunits of glutenin in hexaploid wheat was compiled. Japanese varieties showed some special allelic variation in glutenin HMW subunits that was different from those in hexaploid wheats of other countries. 相似文献
16.
应用~(15)N同位素标记菌体和Tn5转座子诱变的突变株研究固氮粪产碱菌对宿主水稻的联合进程,结果表明,粘附作用是结合过程的第一步,接种3h后粘附在根表的菌体数量达最大值,约占接种量的3.7％。粘附的菌体易脱离根表,表明粘附作用是细菌与宿主植物间的弱的相互作用。在根表定位是结合过程的第二步。接种15h后,定位菌体数量达最大值,约占接种量的21％。经振荡处理不能使定位菌体脱离根表。定殖是结合过程的第三步,接种20h后定殖菌体紧密结合于根表,剧烈振荡亦不易使其脱离根表。定殖后菌体开始出现果胶酶活性。采用趋化(Che)和胞外多糖(Exo)突变株研究表明,趋化性和胞外多糖的合成是影响细菌在根表结合的重要因素。粪产碱菌在水稻根表没有专一的粘附部位,但粪产碱菌的定位和定殖主要发生在主根根表,尤其是主、侧根交接处。 相似文献
17.
The use of capillary electrophoresis in SDS (SDS‐CE) for separation and quantification of HMW glutenin subunits (HMW‐GS) was investigated. HMW‐GS were precipitated with 40% acetone from 50% 1‐propanol extract of flour under reducing conditions after removal of monomeric proteins with 50% 1‐propanol. Poly (ethylene oxide) was used in the running buffer (3% w/v) for SDS‐CE. The results indicated that HMW‐GS could be well separated by SDS‐CE, including subunits 7+8, 7+9, 2+12, 5+10, and 17+18. However, HMW‐GS showed delayed migration times compared with molecular weight protein standards. Some HMW‐GS were reversed in their mobilities in SDS‐CE compared with their mobility and molecular weights by SDS‐PAGE. Therefore, the SDS‐CE was unsuitable for MW determination of HMW‐GS. A linear response was obtained from SDS‐CE of a plot of the concentration of HMW‐GS of the 40% acetone precipitate versus corrected areas for absorbance at 214 nm. Quantification of HMW‐GS for the two biotypes (subunits 5+10 vs. 2+12) of an Australian wheat cultivar Warigal confirmed the differences between the two biotypes in their quantity of HMW‐GS. Therefore, the technique could be used to quantify HMW‐GS in conjunction with SDS‐PAGE. 相似文献
18.
S. Uthayakumaran H. L. Beasley F. L. Stoddard M. Keentok N. Phan‐Thien R. I. Tanner F. Bks 《Cereal Chemistry》2002,79(2):294-300
The high molecular weight glutenin subunits (HMW‐GS) play an important role in governing the functional properties of wheat dough. To understand the role of HMW‐GS in defining the basic and applied rheological parameters and end‐use quality of wheat dough, it is essential to conduct a systematic study where the effect of different HMW‐GS are determined. This study focuses on the effect of HMW‐GS on basic rheological properties. Eight wheat lines derived from cvs. Olympic and Gabo were used in this study. One line contained HMW‐GS coded by all three loci, three lines were each null at one of the loci, three lines were null at two of the loci and one line null at all three loci. The flour protein level of all samples was adjusted to a constant 9% by adding starch. In another set of experiments, in addition to the flour protein content being held at 9%, the glutenin‐to‐gliadin ratio was maintained at 0.62 by adding gliadin. Rheological properties such as elongational, dynamic, and shear viscometric properties were determined. The presence of Glu‐D1 subunits (5+10) made a significantly larger contribution to dough properties than those encoded by Glu‐B1 (17+18), while subunit 1, encoded by Glu‐A1, made the least contribution to functionality. Results also confirmed that HMW‐GS contributed to strength and stability of dough. 相似文献
19.
Coelho E Reis A Domingues MR Rocha SM Coimbra MA 《Journal of agricultural and food chemistry》2011,59(7):3168-3179
The foam of sparkling wines is a key parameter of their quality. However, the compounds that are directly involved in foam formation and stabilization are not yet completely established. In this work, seven sparkling wines were produced in Bairrada appellation (Portugal) under different conditions and their foaming properties evaluated using a Mosalux-based device. Fractionation of the sparkling wines into four independent fractions, (1) high molecular weight material, with molecular weight higher than 12 kDa (HMW), (2) hydrophilic material with molecular weigh between 1 and 12 kDa (AqIMW), (3) hydrophobic material with molecular weigh between 1 and 12 kDa (MeIMW), and (4) hydrophobic material with a molecular weight lower than 1 kDa (MeLMW), allowed the observation that the wines presenting the lower foam stability were those that presented lower amounts of the MeLMW fraction. The fraction that presented the best foam stability was HMW. When HMW is combined with MeLMW fraction, the foam stability largely increased. This increase was even larger, approaching the foam stability of the sparkling wine, when HMW was combined with the less hydrophobic subfraction of MeLMW (fraction 3). Electrospray tandem mass spectrometry (ESI-MS/MS) of fraction 3 allowed the assignment of polyethylene glycol oligomers (n = 5-11) and diethylene glycol 8-hydroxytridecanoate glyceryl acetate. To observe if these molecules occur in sparkling wine foam, the MeLMW was recovered directly from the sparkling wine foam and was also analyzed by ESI-MS/MS. The presence of monoacylglycerols of palmitic and stearic acids, as well as four glycerylethylene glycol fatty acid derivatives, was observed. These surface active compounds are preferentially partitioned by the sparkling wine foam rather than the liquid phase, allowing the inference of their role as key components in the promotion and stabilization of sparkling wine foam. 相似文献
20.
High molecular weight (HMW) or low molecular weight (LMW) subunits of different chemical state (reduced, reoxidized with KBrO3, or KIO3) or gliadins were added in 1% amounts to a base flour of the wheat cultivar Rektor and mixed with water. The corresponding doughs were then characterized by microscale extension tests and by microbaking tests and were compared to doughs from the base flour without additives. The maximum resistance of dough was strongly increased by HMW subunits in a reduced state and by HMW subunits reoxidized with KBrO3. A moderate increase of resistance was caused by HMW subunits reoxidized with KIO3 and by LMW subunits reoxidized with KBrO3 or KIO3. This resistance was strongly lowered by LMW subunits in a reduced state and by gliadins. The extensibility of dough was significantly increased only by gliadins and reduced HMW subunits; HMW subunits reoxidized with KBrO3 had no effect, and all other fractions had a decreasing effect. In particular, glutenin subunits reoxidized with KIO3 induced marked decrease of extensibility, resulting in bell‐shaped curve extensigrams, which are typical for plastic properties. The effect of reoxidized mixtures (2:1) of HMW and LMW subunits on maximum resistance depended on the oxidizing agent and on the conditions (reoxidation separated or together); extensibility was generally decreased. Bread volume was increased by addition of HMW subunits (reduced or reoxidized with KBrO3) and decreased by LMW subunits (reoxidized with KBrO3 or KIO3) and by a HMW‐LMW subunit mixture (reoxidized with KBrO3). The volume was strongly decreased by addition of reduced LMW subunits. A high bread volume was related to higher values for both resistance and extensibility. 相似文献