三种百合鳞茎提取物的抑菌作用

采用纸片琼脂扩散法测定了宜昌百合、岷江百合及兰州百合鳞茎甲醇提取物对革兰氏阳性细菌(金黄色葡萄球菌、枯草芽孢杆菌)和革兰氏阴性细菌(大肠杆菌、沙门氏菌)的抑制活性,并对3种百合鳞茎提取物的含量与抑菌活性进行了剂量-效应关系分析。结果表明:3种百合鳞茎提取物对4种细菌均具有抑制活性,对革兰氏阳性细菌的抑菌活性高于对革兰氏阴性细菌的抑菌活性,且宜昌百合和岷江百合两种野生百合鳞茎提取物的抑菌活性均高于普通食用的兰州百合;3种百合鳞茎提取物的含量与抑菌活性之间存在明显的剂量-效应关系,即随着提取物含量的升高,抑菌活性明显升高。     

木梨幼叶提取物抑菌作用研究

用木梨(yrus xerophila)幼叶提取物对几种常见微生物进行抑菌试验,结果表明：木梨幼叶提取物对多种微生物有明显的抑制作用,对金黄色葡萄球菌、大肠杆菌、枯草杆菌及青霉菌的最低抑菌浓度分别为0．25％,4％,4％,8％,且能耐高温短时的热处理。     

甘草提取物的抑菌作用及其对小鼠免疫功能的影响

目的 研究甘草提取物的最低抑菌浓度及其对小鼠免疫功能的影响.方法 以大肠埃希菌和金黄色葡萄球菌为供试菌.结果 甘草提取物对大肠埃希菌和金黄色葡萄球菌的最低抑菌浓度均为12 mg/mL.甘草提取物能提高小鼠的免疫功能,当甘草提取物浓度为100μg/mL时,与对照组相比,小鼠脾脏T淋巴细胞增殖率为(32.62±1.06)％,B淋巴细胞增殖率为(28.20±1.68)％;腹腔巨噬细胞的增殖率为(40.19 ±2.38)％;腹腔巨噬细胞吞噬能力提高(24.20 ±0.01)％;NK细胞杀伤活力提高(15.83 ±1.02)％;IL-1、IL-2的体外诱生增殖率分别为(12.34±0.72)％、(23.78±1.87)％.结论 甘草提取物能抑制大肠埃希菌和金黄色葡萄球菌的生长,且抑制作用呈剂量依赖性.     

桑叶提取物抑菌作用的研究

研究了桑叶水煎剂对常见微生物的抑菌作用,以及在不同pH值条件下的抑菌效果.结果表明:提取液对霉菌的生长没有明显的抑制作用;对供试细菌有效,其中对微球菌的抑制最强,其次为沙门氏菌和大肠杆菌,对枯草芽孢杆菌的作用较弱.抑菌效果随着桑叶水煎剂浓度的增加而加强.在酸性条件下,桑叶水煎剂的抑菌作用都有不同程度的增加,但效果均不如0.05%苯甲酸钠.     

大青叶和板蓝根提取物的抑菌作用研究

目的：探讨中药大青叶和板兰根的逐级提取物的抑菌作用。方法：采用试管稀释法测定大表吉和板兰根的各级提取物－总浸液、乙醇提取液、正丁醇萃取液对各实验菌的最小抑菌浓度（MIC）。结果：各级提取物对实验菌分别有不同程度的抑菌作用,其中对金黄色葡萄球菌的抑菌作用最为明显;各提取物的抑菌强度依次为：正丁醇萃取液（对三种实验菌均明显抑制：MIC≤62mg/ml)、乙醇提取液（金黄色葡萄球菌：MIC≤62mg/ml、肠炎杆菌：MIC≤125mg/ml、大肠埃希菌MIC≤500mg/ml)、总浸液（仅对金黄色葡萄球菌抑制明显：MIC＝62mg/ml）。结论：大青叶和板蓝根具有广谱抗菌作用,其逐级提取物富集的抑菌活性逐级增强。     

月腺大戟(Euphorbia ebracteolata)根部提取物抑菌作用的测定

以小麦赤霉病病菌（Fusarium graminerum）、油菜菌核病病菌（Sclerotirda scleotiorum）、棉花黄萎病病菌（Verticillium dahliae）、苹果炭疽病病菌（Glomarella cingulata）、甜瓜蔓枯病病菌（Mycosphaerella melonis）为供试病原菌,采用琼胶平板法对月腺大戟根部丙酮提取物进行了离体抑菌活性测定;月腺大戟根部提取物样品供试质量浓度分别设为0．05g／mL,0．1g／mL,0．2g／mL．0．4g／mL四个梯度。测定结果表明：不同浓度月腺大戟根部丙酮提取物对5种供试病原菌均表现为很强的抑菌作用,该研究为月腺大戟根部进一步开发植物性农药提供理论依据。     

几种野生植物提取物抑菌作用研究

本文以乙醇为溶剂,分别提取了瓦松、泽漆及一组中草药配方的有效成分;室内测定了三种提取液对5种植物病原菌(棉花枯萎病菌Fusarium oxysporum f.sp.vasinfectum;小麦赤霉病菌Fusarium graminearum Schw;西瓜枯萎病菌Fusarium oxysporum f.sp.niveum;仙人掌软腐病菌Erwinia chrysanthemi pv.chrysanthemi;魔芋软腐病菌Erwiniacarotovora pv.carotovora)的抑菌作用.结果表明:三种提取物对镰刀菌均有不同程度的抑制作用,且三种提取物的抑菌效果差异显著,其中瓦松的抑菌效果最强.当在50 mL培养基中加入5mL不同提取液时,瓦松对不同镰刀菌的相对抑制率为91.39%～100%;中草药配方提取液对不同镰刀菌的相对抑制率分别为41.11%～85.37%;而泽漆提取液对镰刀菌的相对抑制率仅为12.86%～21.23%;当在50 mL培养基中加入提取液体积降低为2 mL、1 mL、0.5mL时,三种提取液对三种镰刀菌的抑制效果骤然下降,但下降的梯度不一.对大白菜软腐病菌与魔芋软腐病菌而言也是瓦松的抑菌效果最强,中草药配方次之,泽漆的抑制效果最差.     

蒲公英不同部位提取物抑菌作用研究及口服液研制

为检验蒲公英的抗菌活性并制备出口感最佳的蒲公英口服液,试验采用药敏法和最低抑菌浓度值(minimum inhibitory concentration,MIC)检验蒲公英提取物对大肠杆菌和金黄色葡萄球菌的抑菌效果,并以感官特性和黄酮含量为指标,并通过正交试验统计分析确定口服液的最佳工艺组方.结果表明:同浓度下全草水提物...     

杭黄菊提取物的体外抗菌活性研究

本文研究杭黄菊花水提物和醇提物对常见的人体肠道致病菌的抑菌活性。采用超声波提取法获得杭黄菊提取物,用琼脂扩散法测试该粗提物对受试菌的抑菌作用,并用倍比稀释法确定最小抑菌浓度。实验结果表明杭黄菊花水提物和醇提物对常见的7种肠道致病菌具有较强的抑制作用,尤其对变形杆菌、痢疾杆菌和伤寒杆菌的抑制作用较强。采用相同提取方法的高浓度提取物比低浓度提取物具有更显著(P0.01)的抑菌作用,而相同浓度的水提物比醇提物抑菌效果更为明显(P0.01),水提物对相同细菌的最低抑菌浓度(MIC)低于醇提物。杭黄菊提取物对肠道致病菌有明显的抑制作用,可被开发用于抗菌新药研制。     

茶多酚抑菌作用的研究

茶多酚又名茶单宁、茶鞣质,是茶叶中一类以儿茶素为主的多酚类化合物。已证实它有止渴提神、延缓衰老、抗肿瘤、抑制TPA促癌作用,且是很强的氧化剂。笔者用滤纸圆片和牛津杯法,测试茶多酚对十一种细菌、两种酵母、四种霉菌等三大类微生物的抑制作用,以探讨茶多酚新的作用和开拓应用新途径。     

西瓜小孢子发育过程中几种细胞器的变化

用透射电子显微镜观察了西瓜（Ｃｉｔｒｕｌｌｕｓ ｖｕｌｇａｒｉｓ Ｓｃｈｒａｄ．）小孢子发育过程中核糖体、线粒体、质体、内质网、高尔基体等细胞器的变化。核糖体和线粒体变化都有明显的规律性：核糖体密度在四分体时期高,液泡化时期降低,液泡化结束后再回升;线粒体经历一个脱分化与再分化周期,液泡化时期该细胞器数量及其内嵴数目减少而脱分化,液泡化结束后形状多样化、内嵴重新增多而再分化;质体结构不变,但体积变     

西瓜基因转化及其转基因植株再生的研究

西瓜味甜汁多,营养丰富,能消暑、解渴,是夏季重要水果。主要危害是马铃薯Y病毒组(Potyviring group)的西瓜花叶病毒一号(WMV-Ⅰ)和西瓜花叶病毒二号(WMV-Ⅱ)。WMV-Ⅰ和WMV-Ⅱ发病严重,农药防治效果差且存在农药残留问题。目前尚未选育出抗病新品种。近年来,国内外广泛采用植物基因工程方法来选育抗病毒的良种,其中利用外壳蛋     

Effect of benzyladenine on the polypeptide pattern of plastids in excised watermelon cotyledons

We have shown in a previous paper that plastids of watermelon ( Citrullus vulgaris Schrad., cv. Fairfax) cotyledons differentiate into amyloplasts when the cotyledons are grown in water and into prochloroplasts when they are grown in benzyladenine (BA) solution. In the present work we have tested whether this large difference in development of the plastids is accompanied by equally conspicuous changes in their polypeptide pattern. Cotyledons were grown for 4 days in the dark either on distilled water or on 10⁻⁵ M BA. Alternatively they were transfered to 10⁻⁵ M BA after 4 days of growth in water.
Plastids of control cotyledons had a rather simple polypeptide pattern. The only prominent protein bands were the two subunits of ribulose bisphosphate carboxylase (EC 4.1.1.39). Contamination with storage protein was present. Plastids from BA-treated cotyledons had a much more complex polypeptide pattern. No storage protein contamination was observed. Polypeptide bands present only as traces in the control and having molecular weights of 32, 44, 48 and 49 kDa increased in intensity after an exposure of only 6 h to BA. The 32-kDa band seemed to be most dependent on the presence of the hormone. Contrary to what was observed in plastids, BA seemed to have no influence on the polypeptide pattern of mitochondria.     

Starch content and distribution in excised watermelon cotyledons treated with benzyladenine

We have examined the effect of benzyladenine (BA) on amyloplast number and distribution in semithin cross-sections of excised watermelon ( Citrullus vulgaris Schrad ., cv. Fairfax) cotyledons grown in the dark. The sections were stained with Lugol solution and observed with an immersion objective. In control cotyledons, amyloplasts were always more abundant and contain more starch grains than in BA-treated cotyledons. The higher starch content was correlated with a higher ratio between starch synthetase (EC 2.4.1.21) and amylase (EC 3.2.1.1) activities in the controls. In the central zone of the mesophyll, the amyloplasts contained more starch grains than in the abaxial and adaxial (palisade) zones. The average number of amyloplasts per cell was different in the three zones, and followed a different time course in control and treated cotyledons. BA decreased this number, particularly in the adaxial zones. Our data seem to indicate a different function of starch in the central and in adaxial zone of the mesophyll. In the central zone starch is probably used as a source of carbohydrates for export to the embryo axis, while in the adaxial zone, where the transformation from amyloplast to etioplast is particularly pronounced, starch may be a reserve for organelle differentiation. BA stimulates the utilization of starch for both functions.     

特大‘新红宝’西瓜的快速繁殖研究

利用新红宝西瓜种子、茎段、茎尖及腋芽为外植体,接种子改良的ＭＳ培养基上。种子经常规消毒灭菌后,７—１５ｄ后可获得９５％以上的健壮无菌苗．苗高３ｃｍ─５ｃｍ时即可用于有关实验。接种６ｄ后,茎段两端切口处膨大,２８—３５ｄ后出现愈伤组织,出愈率达到６８％。接种５ｄ后,茎尖明显长大。在本实验的激素组合中．３５ｄ后,茎尖周围均出现了不同数量的腋芽。最好的组合为改良的ＭＳ＋２．５ｍｇ／ＬＢＡ＋ＩＡＡ１ｍｇ／Ｌ,可使一个茎尖在３５—４２ｄ后扩增为１８─２１个芽并逐渐长成无根苗。４７ｄ后,转入改良ＭＳ＋ＮＡＡ０．５ｍｇ／Ｌ培养基中．生根率达到９４％以上。２８ｄ后,将苗移到田间,第一批移苗５００株,成活４３８株,成活率达到８７．６％。     

Functional Analysis of the N-Terminal Prepeptides of Watermelon Mitochondrial and Glyoxysomal Malate Dehydrogenases*

Mitochondrial and glyoxysomal malate dehydrogenase (mMDH; gMDH; L-malate: NAD⁺ oxidoreductase; EC 1.1.1.37) of watermelon (Citrullus vulgaris) cotyledons are synthesized with N-terminal cleavable presequences which are shown to specify sorting of the two proteins. The two presequences differ in length (27 or 37 amino acids) and primary structure. Precursor proteins of the two isoenzymes with site-directed mutations in their presequences and hybrid precursor proteins with reciprocally exchanged presequences were analyzed for proper import using two approaches, namely in vitro using isolated watermelon organelles or in vivo after synthesis in the heterologous host, Hansenula polymorpha. The mitochondrial presequence is essential and sufficient to target the mature glyoxysomal isoenzyme into mitochondria (Gietl et al., 1994). As to the function of the mitochondrial presequence a substitution of ^?3R (considered important for one step precursor cleavage in yeast and mammals) with ^?3L permitted import into mitochondria but cleavage of the transit peptide and conversion into active mature enzyme was impeded. Substitution of ^?13R^?12S (in a sequence reminiscent of the octapeptide motif serving as a substrate for the mammalian and yeast intermediate peptidase) into ^?13L¹²F permitted mitochondrial import and processing like the wild type transit peptide. Purified rat mitochondrial processing protease, which can effect single step cleavage of mitochondrial protein precursors, cleaves in vitro translated watermelon mMDH precursor into its mature form. The glyoxysomal presequence is essential and sufficient to target the mature mitochondrial isoenzyme into peroxisomes of Hansenula polymorpha, but these peroxisomes lack a processing enzyme to cleave the presequence (Gietl et al., 1994). We here show that isolated watermelon organelles also import the hybrid proteins in vitro and process the glyoxysomal presequence. Site directed mutations within the conserved RI-X₅-HL-motif impede efficiency of import and cleavage by watermelon organelles.     

抗菌肽体外对结核杆菌的作用初探

将结核杆菌接种于含抗菌肽的苏通氏培养基中 ,在接种后不同时间内取样接种于罗氏培养基上 ,观察结核杆菌在罗氏培养基上的生长情况 ,初步探讨了抗菌肽 (CecropinB)对结核杆菌标准株H3 7RV的作用。结果显示 ,接种 10天后在罗氏培养基上结核杆菌对抗菌肽敏感。说明在体外培养中 ,抗菌肽有一定的抗结核杆菌的作用     

Antioxidant role of glutathione associated with accelerated aging and hydration of triploid watermelon seeds

Hydration offers an effective means for raising seed performance in many crop species. The objective of the present study was to evaluate the effect of hydration in vermiculite on germinability and antioxidant capacity of glutathione in artificially aged triploid seeds of two watermelon cultivars. Aging was achieved by incubating the seeds at 45°C and 79% relative humidity for 6 days and then air-drying them to their original moisture level (4%). Hydration was achieved by mixing untreated and aged seeds with moist vermiculite No. 3 at 25°C for 24 h. The partially hydrated seeds were air-dried at 25°C for 36 h to 4.7% moisture level. Aged seeds germinated more slowly and poorly than unaged seeds. Aging also decreased the level of glutathione and reduced the activity of several enzymes involved in glutathione antiperoxidation. The germinability of aged triploid seeds was restored partially by hydration in vermiculite. The glutathione content and the activity of antiperoxidative enzymes using glutathione as substrate were also increased by hydration. The changes in germination and glutathione level in relation to aging and hydration were similar for the two cultivars, despite differences in their germination performance and related physiological traits.