脱共生作用对黑豆蚜氨基酸代谢的影响(英文)

为了解共生菌对黑豆蚜蛋白质、氨基酸代谢的影响 ,用利福平处理黑豆蚜以除去其细胞内共生细菌 ,产生脱共生蚜虫。结果表明 ,被脱去共生菌的蚜虫与未经抗生素处理的正常蚜虫相比 ,7日龄时 ,脱共生蚜虫每毫克鲜重的总蛋白含量降低了 2 9% ,每毫克鲜重的游离氨基酸含量提高了 17%。对黑豆蚜取食的蚕豆苗韧皮部组织中必需氨基酸所占的比例进行分析后发现 ,蚕豆苗韧皮部组织中的必需氨基酸含量仅占 2 0 % ,而有共生菌的黑豆蚜组织中必需氨基酸已达到 4 4% ,脱共生后降低到 37% ,这些结果证明了黑豆蚜的胞内共生菌为其寄主提供了部分必需氨基酸。通过对游离氨基酸组成的分析发现 ,在测定的 17种氨基酸中 ,必需氨基酸中的苏氨酸在共生蚜虫中所占的比例为 2 1 6 % ,在脱共生蚜虫中仅为 16 7%。同样 ,非必需氨基酸中的酪氨酸和丝氨酸 ,在共生蚜虫中分别占总游离氨基酸的 8 9%和 5 6 % ,而在脱共生蚜虫中却分别升高到 2 1 1%和 13 6 %。这些结果表明 ,各种氨基酸比例的失调 ,造成了脱共生蚜虫蛋白质合成受阻和部分游离氨基酸的积累 ,并因此导致蚜虫发育和繁殖的失调。     

江浙蝮蛇毒L—氨基酸氧化酶的分离纯化及其性质鉴定

从江浙蝮蛇粗毒中经SephadexG 15 0凝胶过滤、DEAE SepharoseCL 6B以及FPLCSuperose 12分离出一种蛋白质。该蛋白质经SDS PAGE测定在非还原和还原条件下分子量均为 5 7kD左右 ,等电聚焦测得其等电点约为 4.9。生物活性测定表明该蛋白质具有L 氨基酸氧化酶活性 ,能够抑制由ADP和胶原所引起的血小板聚集 ,具有抑制革兰氏阴性菌的作用 ;并且具有细胞毒性 ,能够诱导细胞凋亡     

烟蚜为害的经济损失研究

陕西渭北烟草种植区迁飞到烟田的蚜虫有6种,但只有桃蚜Myzus persicae(Sulzer)能够建立种群,造成为害。从烟草旺长开始,按烟株上蚜量和蚜虫分泌蜜露,引起霉菌滋生,污染叶面积的比例分为0、I、II、III、IV级。以未受蚜害的0级为对照,受蚜害的I、II、III、IV级的中上等烟下降分别为6.93%、13.05%、28.51%和30.94%,经济损失率分别为9.86%、23.81%、36.12%和39.59%。化学成分分析表明：I、II、III和IV级烟叶的烟碱含量分别降低10.61%、19.29%、10.61%和25.40%,还原糖分别降低15.04%、19.23%、40.98%和44.86%,蛋白质含量分别提高16.17%、31.99%、37.02%和38.72%。这就表明桃蚜为害既影响烤烟的外观质量、又影响内在品质。1头蚜虫经济损失率＝0.0695%。     

蜡蚧轮枝菌VL17中杀虫成分分离及鉴定北大核心CSCD

蜡蚧轮枝菌（Verticilliumlecanii）VL17菌株是从罹病的蚜虫中分离得到的一种具有高效杀虫活性的内生真菌。根据生物活性跟踪测试,采用不同溶媒萃取法、硅胶柱分离法、高速逆流色谱法、半制备高效液相分离纯化法,从该菌株的代谢产物中筛选出具有杀蚜虫的有效成分。实验结果表明：经察氏液体培养基培养采用乙酸乙酯提取获得粗毒素对萝卜蚜若蚜的毒杀活性最好;该提取物经HSCCC、HPLC分离纯化后收集到4个馏分,其中馏分Ⅲ对萝卜蚜的防治效果最佳,LC50值为0．4748mg／mL;馏分Ⅲ通过IR、MS初步鉴定推测结果为羧酸酯类化合物,分子量约为437。     

正常与患白内障大鼠晶状体中脲溶性蛋白质性质的研究

本文研究了正常及三种类型白内障大鼠晶状体中脲溶性蛋白质的含量及性质的变化,发现在每种类型白内障晶状体中,水溶性蛋白质均减少,水不溶性蛋白质则都相对增加。经SephadexG-200柱层析及SDS聚丙烯酰胺凝胶电泳发现,晶状体中脲溶性蛋白质主要是由二硫键交联而成的高分子聚合物。经巯基乙醇还原后,绝大部分高分子聚合物可分解成低分子量蛋白质,其分子量与水溶性的γ晶体蛋白相同。这提示晶状体中脲溶性蛋白质的主要成分很可能是以二硫键交联而成的γ晶体蛋白聚合物。此结果与本实验室所得白内障晶状体水溶性蛋白质的变化相吻合。     

黄鳝孵卵泡的生化成分及其生理作用

通过对繁殖季节黄鳝为孵卵所吐的泡沫的特性和生化成分分析 ,孵卵泡的黏度为 2 72mPaS ,证明了该孵卵泡是糖蛋白 ,其中糖类含量为 0 15 6mg/mL ,蛋白质含量为 0 2 5 0mg/mL ,蛋白质 /糖类比值为 1 6 0。分离的泡沫蛋白经SDS PAGE电泳含 4种组分 ,分子量从小到大依次为 4 2 5kDa、5 8 6kDa、6 5 3kDa、98 2kDa。泡沫蛋白含 16种氨基酸 ,氨基酸总含量为 2 0 1 88mg/ 10 0mL。同时对孵卵泡的生理作用进行了分析和讨论     

花期杭白菊植株引诱菊小长管蚜的嗅觉和视觉线索及应用

杭白菊是一类顶级的茶用菊,原产地是浙江省桐乡市。菊小长管蚜Macrosiphoniella sanborni是菊属植物重要害虫,常常在花期觅食于花上和匿于花内,随着菊花采摘、加工而残留在菊花产品中。冲饮菊花茶过程中,蚜尸或肢体就浮现在菊花茶汤中,致饮者“倒胃口”。为揭示该蚜嗜好花朵原因和研制有效的防控手段以便在花期控制该蚜,分离鉴定了花期杭白菊植株的36种挥发性化合物,挑选其中含量大的、主要的17种用作味源,对该蚜做行为测定。发现a-蒎烯、反-2-己烯醛、(+)-4-蒈烯、顺-3-己烯乙酯、顺式-β-罗勒烯、γ-萜品烯、或者1-辛烯-3-乙酯7种成分的10^-4g/mL的正己烷溶液显著地吸引该蚜雌、雄成蚜。依次将该7种成分的每种10^-2g/mL正己烷溶液与蚜虫性信息素荆芥内酯的10^-4g/mL正己烷溶液按照60∶10∶10∶2∶2∶20∶2∶1体积比配制成复合型蚜虫引诱剂,在菊园中与专利产品蚜虫引诱剂比较诱效,结果表明前者对于该蚜更具有引诱力。此外,在杭白菊园进行的该蚜趋色行为测定中,测得菊花黄对该蚜诱效稍强于芽绿色。随后...     

DNA条形码快速鉴定广州木槿蚜虫

为快速、准确鉴定木槿蚜虫,本文在广州市30个采样点采集了木槿蚜虫样本64份,利用DNA条形码技术获得了64份线粒体细胞色素C氧化酶亚基I(COI)基因的658 bp序列,同时利用形态鉴定和DAN条形码鉴定确定其中共包括5种蚜虫,棉蚜Aphis gossypii Glover、绣线菊蚜Aphis spiraecola Patch、苹果蚜Aphis pomi de Geer、月季长管蚜Sitobion rosivorum(Zhang)和桃蚜Myzus persicae(Sulzer)。所有样品的种内平均遗传距离为0.30%(0~2.30±0.36%),种间平均遗传距离为9.00%(3.30%~10.90±1.22%)。邻接法(neighbor-joining,NJ)构建的系统发育树显示采自30个采样点木槿上的5种蚜虫分别聚为一支,支持率达99%。所获DNA条形码对指导木槿的蚜虫防治有一定的指导意义。     

早春寄主与棉花上蚜虫和蚜茧蜂的相互关系观察

作者通过田间调查和室内接种观察,22种早春寄主上的蚜虫经鉴定有16个种,其中5个优势种。在棉苗上强迫接种均能生存,但只有14种寄主上的蚜虫能在棉苗上繁殖后代。四川早春气温回升快,蚜虫和蚜茧蜂均出现早。棉田周围5种早春寄主上的蚜茧蜂强迫接种能寄生棉蚜。油菜、大白菜上蚜茧蜂寄生棉蚜的寄生率高达80％以上,说明早春寄主上的蚜茧蜂与大田宿主有相互转移关系。     

三种杀虫剂对麦田蚜虫和天敌的影响

通过对施用杀虫剂吡虫啉、抗蚜威、广谱性杀虫剂氧化乐果对麦田蚜虫和天敌的影响进行分析 ,结果表明 ,施用杀虫剂对麦田蚜虫防效高 ,对其天敌有保护作用 ,且瓢蚜比降低。使用 1 0 %吡虫啉( 1 0g 667m2 )后 5～ 2 5天瓢蚜比为 1∶34～ 1∶1 70 ;用 50 %抗蚜威 ( 5g 667m2 )后 1 0～ 2 0天瓢蚜比为 1∶31～1∶1 95;而广谱性杀虫剂氧化乐果 ( 50mL 667m2 )对麦田蚜虫防效好 ,对天敌杀伤力大 ,药后 1 5天瓢蚜比为1∶2 65。施用化学农药可使蚜茧蜂寄生率提高。     

Storage proteins are present in the hemolymph from larvae and adults of the Colorado potato beetle.

The protein composition of larval and adult hemolymph from the Colorado potato beetle, Leptinotarsa decemlineata, was investigated and some abundant, high molecular weight proteins were identified and characterized. Diapause protein 1, which occurs in the hemolymph of last instar larvae and short-day adults, appeared to be a storage protein. This protein dissociated into two bands due to the high pH used in nondenaturing gels. Its quaternary structure was established by chemical crosslinking. It appeared to be a hexamer. Diapause protein 1 is composed of approximately 82,000 subunits. The amino acid composition and N-terminal sequence of this protein has been determined. Specific antibodies against diapause protein 1 have been developed. Topical application of 1 microgram pyriproxyfen, a juvenile hormone analog, to last instar larvae and short-day adults suppressed the appearance of this protein in the hemolymph. Pyriproxyfen prematurely induced vitellogenin, when applied to last instar larvae. A larval specific protein was also identified in the hemolymph. Its temporary appearance in the hemolymph of last instar larvae, its subunit composition (M(r) approximately 82,000) and its suppression by pyriproxyfen suggests that this protein is a storage protein as well.     

Expression of a bacterial α-amylase gene in transgenic rice seeds

An alpha-amylase gene from Bacillus stearothermophilus under the control of the promoter of a major rice-seed storage protein was introduced into rice. The transgenic line with the highest alpha-amylase activity reached about 15,000 U/g of seeds (one unit is defined as the amount of enzyme that produces 1 mumol of reducing sugar in 1 min at 70 degrees C). The enzyme produced in the seeds had an optimum pH of 5.0-5.5 and optimum temperature of 60-70 degrees C. Without extraction or purification, the power of transgenic rice seeds was able to liquify 100 times its weight of corn powder in 2 h. Thus, the transgenic rice could be used for industrial starch liquefaction.     

Isolation and function of a low molecular weight protein of mung bean embryonic axes

A low molecular weight protein from dry mung bean (Vigna radiata) embryonic axes has been purified to near homogeneity by chromatography on DEAE-cellulose and hydroxylapatite. It shows a molecular weight of about 12,000 in sodium dodecyl sulfate-polyacrylamide gels and a sedimentation coefficient of about 2 S in sucrose gradients. This protein occurs in greater amounts in dry axes than in dry cotyledons, and it dramatically disappears during early germination of the seed. Affinity chromatography tests do not indicate it as a trypsin inhibitor or as a glycoprotein. It is a water-soluble cytoplasmic protein exhibiting an amino acid composition characteristic of storage proteins with a high content of glutamic acid/glutamine. We suggest that it is a low molecular weight storage albumin.Abbreviations Asx aspartic acid/asparagine - BSA bovine serum albumin - Con A concanavalin A - EB extraction buffer - Glx glutamic acid/glutamine - HA hydroxylapatite - PB phosphate buffer - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis - TCA trichloroacetic acid     

Characterization of the single-stranded DNA binding protein pV(VGJΦ) of VGJΦ phage from Vibrio cholerae

pV(VGJΦ), a single-stranded DNA binding protein of the vibriophage VGJΦ was subject to biochemical analysis. Here, we show that this protein has a general affinity for single-stranded DNA (ssDNA) as documented by Electrophoretic Mobility Shift Assay (EMSA). The apparent molecular weight of the monomer is about 12.7kDa as measured by HPLC-SEC. Moreover, isoelectrofocusing showed an isoelectric point for pV(VGJΦ) of 6.82 pH units. Size exclusion chromatography in 150mM NaCl, 50mM sodium phosphate buffer, pH 7.0 revealed a major protein species of 27.0kDa, suggesting homodimeric protein architecture. Furthermore, pV(VGJΦ) binds ssDNA at extreme temperatures and the complex was stable after extended incubation times. Upon frozen storage at -20°C for a year the protein retained its integrity, biological activity and oligomericity. On the other hand, bioinformatics analysis predicted that pV(VGJΦ) protein has a disordered C-terminal, which might be involved in its functional activity. All the aforementioned features make pV(VGJΦ) interesting for biotechnological applications.     

重要谷类种子贮藏蛋白的特性及改良研究

在成熟谷类种子中,总蛋白约为种子干重的7％～16％,其中大部分为贮藏蛋白。这些贮藏蛋白对于人类和牲畜所需要的营养质量以及在食品加工中都有重要的影响。本文对一些重要谷类种子贮藏蛋白的组成特性以及利用基因工程技术提高谷类种子蛋白质含量和质量进行了全面综述。此外,还简要介绍了在利用基因工程改良谷物种子品质中可能产生的食品安全性问题、如何增加外源基因的表达量和全面提高谷类种子蛋白质含量以及解决的办法。     

Characterization of 2S seed storage protein of Brassica campestris and its antigenic homology with seed proteins of other Cruciferae.

The low molecular weight seed storage protein of Brassica campestris has been isolated and its amino acid composition determined. Antibody raised against this low molecular weight protein has been used to compare the antigenic similarity between the low molecular weight storage proteins of different Cruciferae seeds by immunoprecipitation and Western blotting. These studies revealed the existence of antigenically homologous proteins of identical molecular weights in seeds of other Cruciferae but absent in some other dicots like mung bean and tobacco seeds.     

Properties of a small basic Peptide from pumpkin seeds

A small basic peptide with an unusual amino acid composition has been isolated from the seeds of pumpkin, Cucurbita maxima. Amino acid analysis and sequence data show the protein to be about 36 residues in length, with an approximate composition Lys₁, Arg₁₄, Asp₃, (Glu + Gln)₁₅, Gly₁, Pro₁, Trp₁. On the basis of composition, the molecular weight is approximately 5000 daltons and the nitrogen content by weight is 20.4%. Twelve amino acids are entirely lacking. The peptide is slightly toxic to mouse B-16 melanoma cells, but its in vivo function is unknown. It does not appear to be derived from cucurbitin, the pumpkin storage globulin; however, it could be a storage peptide involved in nitrogen mobilization during the early stages of germination.     

Specific Removal of Proteins from the Envelope of Escherichia coli by Protease Treatments

When the envelope fraction of Escherichia coli was treated by trypsin, about 40% of total envelope proteins were removed from the fraction without changing its phospholipid content. Analysis of envelope proteins by acrylamide gel electrophoresis in 0.5% sodium dodecyl sulfate revealed that trypsin treatment was very specific; one of the major proteins (molecular weight, 38,000) and all proteins of molecular weight greater than 70,000 were completely removed by the treatment. On the other hand, three other major proteins were found to be resistant to the treatment, including protein Y, which was previously shown to be related to deoxyribonucleic acid replication. The trypsin treatment of the envelope fractions composed of a five electron-dense layered structure formed vesicles with a triple-layered membrane (two electron-dense layers). Pronase treatment of the envelope fraction removed about 60% of the envelope proteins without changing its phospholipid content. A major protein of molecular weight of 58,000 was found to be the only protein resistant to the Pronase treatment. Application of these treatments is useful for purification and structural studies of envelope proteins.     

Isolation and some properties of a new fiber-forming protein from Tetrahymena pyriformis

Isolation and characterization of a fibrous protein component which might be associated with contractile ring of a dividing Tetrahymena cell were attempted by making use of coprecipitation of the protein with rabbit skeletal muscle myosin. The protein was purified to homogeneity by ammonium sulfate fractionation between 40--70% saturation and column chromatography of Sephadex G-200, starting from KCl-extract of Tetrahymena acetone powder. Its molecular weight was calculated to be 38,000, based on the electrophoretic mobility in sodium dodecyl sulfate (SDS)-polyacrylamide gel, whereas molecular weight of its native state was determined to be 140,000 by gel filtration on Sephadex G-200, and its sedimentation coefficient was about 9S as estimated by sucrose density gradient centrifugation. The latter was a particle of 7.7 nm in diameter under an electron microscope and supposed to be a tetramer of the 38,000-dalton protein. The protein is considered to be a new, unique protein, since it is definitely different from the ubiquitous non-muscle actin in molecular weight, polymerizability in KCl solution and amino acid composition, and it also different from tropomyosin and tubulin in immunological characteristics and amino acid composition.     

Purification and reconstitution of the proton-pumping ATPase of fungal and plant plasma membranes

The 11S storage protein (glycinin) of soybean [Glycine max (L.) Merr., cv. Raiden] was studied by polyacrylamide gel electrophoresis and amino acid sequence analysis. It contained the following subunits composed of acidic (A) and basic (B) polypeptides: A1aB2, A1bB1b, A2B1a, and A3B4. However, it lacked polypeptides A4, A5, and B3 which are present in many other cultivars. A new acidic polypeptide called A6 was present in a low amount and was characterized by amino acid sequence analysis. It was homologous to A4, although of a smaller apparent molecular weight. Since Raiden has an average protein content of about 40% and its glycinin fraction can be purified as a 350,000 D complex which is typical of other cultivars, the results imply polymorphism with respect to glycinin subunit composition. Because there is a wide variation in the methionine content of the various subunits, these findings suggest the possibility of genetically manipulating the nutritional quality of soybean seed protein by altering glycinin subunit composition.