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41.
【背景】杨树溃疡病是一种主要由葡萄座腔菌引起的杨树枝干病害,危害严重。前期从杨树中分离到一株内生拮抗细菌N6-34,研究表明该菌株拮抗效果好,对多种植物病原菌均有较强的拮抗作用。【目的】对拮抗细菌N6-34产生的抗菌活性物质进行分离纯化,并鉴定了活性物质组分的结构。【方法】通过硫酸铵盐析、甲醇抽提、分子筛、高效液相色谱等方法分离纯化N6-34菌株的抗菌活性物质,并对其进行结构鉴定。【结果】N6-34菌株发酵液经多步分离纯化,共获得14个组分,其中有13个组分具有抗菌活性,经一级质谱分析,获得了13种抗菌活性组分的分子量;经二级质谱分析,将13种抗菌活性物质鉴定为Fengycin A或Fengycin B的同系物或同分异构体。【结论】从N6-34菌株发酵液中分离获得了13种抗菌成分,为杨树溃疡病的生物防治提供了理论依据。 相似文献
42.
目的建立长爪沙鼠原代肝细胞分离培养体系。方法以雄性长爪沙鼠为供体,采用组织消化法和Seglen两步灌流法分离肝细胞,以台盼蓝染色检测细胞得率和活率,过碘酸-希夫氏反应(PAS)鉴定肝细胞,倒置显微镜观察肝细胞形态变化,并使用含有多种细胞因子的培养基维持培养。结果组织消化法和Seglen两步灌流法平均每只长爪沙鼠可分别获得肝细胞(1.33±0.34)×107个、(3.97±1.15)×107个,细胞活率分别为(29.4±6.05)%、(80.3±4.56)%,这两种方法在细胞得率及活率方面存在显著差异。肝细胞内因有大量的糖原颗粒,经PAS染色后被染成红色。结果表明肝细胞在贴壁后72 h内,肝细胞形态发生显著变化。结论采用胶原酶经肝门静脉灌流分离肝细胞是一种高效获得肝细胞的方法。各种细胞因子有利于维持肝细胞在体外的生长分化,长爪沙鼠原代肝细胞分离培养体系的建立将为肝脏相关疾病研究和防治药物的开发提供技术支持。 相似文献
43.
蒙古高原岩黄芪属植物的分支分类学研究 总被引:6,自引:0,他引:6
以蒙古高原岩黄芪属植物为对象, 应用徐克学的最大同步法, 探讨了蒙古高原岩黄芪属(豆科)植物的系统演化, 并根据分支分类结果对蒙古高原岩黄芪属进行了系统学处理。作者首次将蒙古高原岩黄芪属分为岩黄芪亚属、半灌木岩黄芪亚属(新拟)和无刺岩黄芪组、丛枝岩黄芪组、无茎岩黄芪组、半灌木岩黄芪组等4 个组。本文对蒙古高原岩黄芪组的划分符合苏联植物志(1945)中的观点。 相似文献
44.
Molecular evolution of cytochrome c oxidase: rate variation among subunit VIa isoforms 总被引:3,自引:1,他引:2
Schmidt TR; Jaradat SA; Goodman M; Lomax MI; Grossman LI 《Molecular biology and evolution》1997,14(6):595-601
Cytochrome c oxidase (COX) consists of 13 subunits, 3 encoded in the
mitochondrial genome and 10 in the nucleus. Little is known of the role of
the nuclear-encoded subunits, some of which exhibit tissue-specific
isoforms. Subunit VIa is unique in having tissue-specific isoforms in all
mammalian species examined. We examined relative evolutionary rates for the
COX6A heart (H) and liver (L) isoform genes along the length of the
molecule, specifically in relation to the tissue-specific function(s) of
the two isoforms. Nonsynonymous (amino acid replacement) substitutions in
the COX6AH gene occurred more frequently than in the ubiquitously expressed
COX6AL gene. Maximum-parsimony analysis and sequence divergences from
reconstructed ancestral sequences revealed that after the ancestral COX6A
gene duplicated to yield the genes for the H and L isoforms, the sequences
encoding the mitochondrial matrix region of the COX VIa protein experienced
an elevated rate of nonsynonymous substitutions relative to synonymous
substitutions. This is expected for relaxed selective constraints after
gene duplication followed by purifying selection to preserve the
replacements with tissue-specific functions.
相似文献
45.
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47.
Self-Transfer and Genetic Recombination Mediated by P, the Sex Factor of Vibrio cholerae 总被引:15,自引:2,他引:13
Vibrio cholerae cells, infected with the sex factor P, produce discrete, plaque-like clearings when plated on lawns of P(-) cells. We investigated the nature of these clearings and conclude that they are probably sites of active mating. We developed a quantitative assay for P(+) cells and used it to study the kinetics of sex factor spread in broth cultures. Both established and newly infected donor populations were efficient sex factor donors, indicating that P is not self-repressed. We also investigated the kinetics of recombinant formation in broth matings. In 1-hr matings, we routinely found recombination frequencies of 10(-6) per donor cell. Kinetic studies of recombinant formation showed that the markers tested all appeared at early times. Thus P, the V. cholerae sex factor, seems to resemble F in its transfer properties. 相似文献
48.
49.
Zoe Inman Helen Martin SA Paul Chubb 《The Clinical biochemist. Reviews / Australian Association of Clinical Biochemists》2009,30(3):141-151
Background
The lack of guidelines on reporting standards for protein electrophoresis may have led to significant differences in reports from different laboratories.Objective
To determine the extent of variation in reporting of protein electrophoresis results in Australia and New Zealand.Method
Questionnaires were distributed to laboratories throughout Australia and New Zealand asking about protein electrophoresis practices and reporting.Results
Extensive variation was found in the following reporting practices: (a) units for urine Bence Jones protein (BJP); (b) reporting absence of a paraprotein rather than a normal pattern; (c) numerical reporting of all protein fractions or only the paraprotein; (d) warning of possible inaccuracy in the serum immunoglobulin result of the paraprotein type; (e) co-migration of a paraprotein with a normal serum protein; (f) use of a confirmatory test when a known paraprotein is no longer detectable.Conclusions
A working party should be established to make recommendations on the reporting of protein electrophoresis. Implementation of such recommendations should reduce both report variation between laboratories and the risk of misinterpretation of reports. 相似文献50.
Jenny Knapp Jean-Mathieu Bart Patrick Giraudoux Marie-Louise Glowatzki Isabelle Breyer Francis Raoul Peter Deplazes Georg Duscher Karel Martinek Pavol Dubinsky Marie-Hélène Guislain Florence Cliquet Thomas Romig Andrzej Malczewski Bruno Gottstein Renaud Piarroux 《PLoS neglected tropical diseases》2009,3(6)