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影响大肠杆菌噬菌体f2计数的因素 总被引:3,自引:0,他引:3
影响大肠杆菌噬菌体f2计数的因素军事医学科学院卫生学环境医学研究所(天津300050)王新为芮期义高明晁福寰作为人类肠道病毒的指示微生物大肠杆菌噬菌体f2已被广泛应用与研究[1~4]。因其物理、化学性质、颗粒大小以及对外界环境耐力与人类肠道病毒相似[... 相似文献
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金葡菌固相抗体吸附水样中f2噬菌体的效果 总被引:1,自引:0,他引:1
采用金葡菌固相抗体技术特异地吸附水样中的f2噬菌体获得较好的效果。先用滤料物理吸附f2噬菌体,然后用3X肉汤洗脱,再用金葡菌固相抗体特异地吸附洗脱液中的f2噬菌体。结果,当金葡菌固相抗体与洗脱液的体积比=1:10,样品中f2噬菌体的浓度为104~100时,吸附率可达80%~100%,并使f2噬菌体浓缩近50倍,为进一步PCR检验提供了条件。本法操作简便、灵敏度高、特异性强、金葡菌固相抗体可冷冻干燥,便于长期保存。 相似文献
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微电流协同氯对水中大肠杆菌噬菌体f2的灭活效应 总被引:2,自引:0,他引:2
目的 观察微电流(DC)与游离氯(FC)对水中大肠杆菌噬菌体f2的协同灭活效果。方法 用电流密度0.4-1.2mA/m2协同游离氯0.2~0.3mg/L对水中大肠杆菌噬菌体f2进行了灭活试验,用Berenbaum方法判断微电流与氯灭活病毒有无协同效应,并比较单独氯处理与协同处理的灭活效果。结果 电流密度达到0.4 mA/cm2对水中大肠杆菌噬菌体f2有弱灭活作用,电流密度0.6 mA/cm2与游离氯0.2mg/L或电流密度0.4 mA/cm2与游离氯0.3 mg/L有协同灭活效应,且灭活率K值与单独用氯比较,差异有显著性(P<0.05)。水的pH值低、硬度高及有机物含量低时,电氯协同有较好的灭活效果。结论 电流密度达到一定强度时协同游离氯可提高低浓度氯对水中大肠杆菌噬菌体f2灭活的效果。 相似文献
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目的 研究臭氧灭活水中f_2噬菌体的效果.方法 分别向不同pH值(6.5~8.5)、不同色度(O-30度)的臭氧水(通气5~30min)中加入f_2噬菌体悬液原液(终浓度为10~4~10~5pfu/ml),作用5、15、30min后进行f_2噬菌体计数,并计算灭活率.结果 在相同的通气条件下,pH值对臭氧灭活f_2噬菌体效果的影响并不明显;随着色度的提高,臭氧对f_2噬菌体的灭活效果有所降低.结论 高色度的水质条件不利于臭氧灭活水中f_2噬菌体.Abstract: Objective To observe the efficacy of ozone in the inactivation of f_2 phage in water. Methods The concentration of ozone in water was measured by iodometry. During the experiment, the suspension of f_2 phage was added in the ozonized water, at 5,15,30 min, the f_2 phage inactivation rate was calculated. Results Under the same condition of ventilation,in the range of pH regulated in the drinking water sanitary standard,the effect of pH on the inactivation of f_2 phage was not obvious, while the chromaticity of water could remarkably influence the inactivation of f_2 phage. Conclusion The higher chromaticity of water can interfere the inactivation of f_2 phage in water by ozone. 相似文献
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氯和二氧化氯灭活f2噬菌体机理的初步探讨 总被引:5,自引:0,他引:5
探讨氯和二氧化氯单独或联合灭活f2噬菌体对其蛋白质外壳的影响。高剂量的氯或二氧化氯灭活f2噬菌体破坏其抗原性及吸附宿主菌的能力。低剂量的氯灭活f2噬菌体其抗原性仍有保留,低剂量的二氧化氯灭活f2噬菌体则破坏其抗原性。两者联合灭活f2噬菌体,结果与二氧化氯单独作用相似。 相似文献
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[目的]研究二氧化氯对大肠杆菌F2噬菌体消毒效果及将大肠杆菌F2噬菌体作为评价消毒效果的指示微生物的可行性进行评价,同时观察残留二氧化氯浓度衰减速度。[方法]采用悬液定量杀菌试验,观察大肠杆菌F2噬菌体对常用化学消毒剂二氧化氯的抵抗力。[结果]二氧化氯投加量为1 mg/L时,作用10 min,对大肠杆菌F2噬菌体的杀灭对数值4.0;作用30 min,染菌水样中残留二氧化氯浓度分别降解为0.35 mg/L;二氧化氯投加量为2 mg/L时,作用3 min,对大肠杆菌F2噬菌体的杀灭对数值4.0;作用30 min,染菌水样中残留二氧化氯浓度分别降解为0.68 mg/L。[结论]大肠杆菌F2噬菌体对二氧化氯消毒剂,在常规剂量作用下,可有效灭活大肠杆菌F2噬菌体。因此选择大肠杆菌F2噬菌体作为病毒消毒试验的指示微生物,可明显缩短病毒灭活效果评价周期。二氧化氯衰减速度随浓度和时间的变化而加快。 相似文献
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目的:了解常用消毒剂对大肠杆菌O157:H7的杀灭效果和指导现场消毒实践。方法:采用能量试验和模拟现场试验,对4种消毒剂进行了实验室观察。结果:能量试验测出各种消毒剂最低有效杀灭浓度分别为:二氯异氢尿酸钠有效氯为100mg/L、碘伏有效碘为50mg/L、洗必泰为25mg/L、季铵盐为100mg/L。模拟现场试验结果,完全杀灭河水、井水及医院污水中污染的试验菌所需各消毒剂的剂量分别为:二氯异氢尿酸钠有效氯20.0mg/L、10.0mg/L和10.0mg/L,均需作用1h;碘伏有效碘10.0mg/L作用8h、5.0mg/L作用1h和40.0mg/L作用8h;洗必泰10.0mg/L、5.0mg/L和40.0mg/L,均需作用2h;季铵盐20.0mg/L作用1h、10.0mg/L作用lh和80.0mg/L作用2h。完全杀灭泥土和田间土壤载体中试验菌所需各消毒剂剂量分别为:二氯异氢尿酸钠有效氯250mg/L作用1min和400mg/L作用1min;碘伏有效碘90mg/L作用5min和120mg/L作用5min;洗必泰90mg/L作用1min和120mg/L作用5min;季铵盐为250mg/L作用1min和400mg/L作用5min。结论:试验结果对于有效切断大肠杆菌O157:H7传播途径、控制医院感染以及进一步研究该菌有重要意义。 相似文献
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Moyasar T. Yahya Timothy M. Straub Charles P. Gerba Aaron B. Margolin 《International journal of environmental health research》1991,1(2):76-86
Survival of bacteriophage MS‐2 and poliovirus was evaluated in new and aged copper, galvanized and plastic polymer (polybutylene, cross‐linked polyethylene, polyvinylchloride) pipes. Inactivation rates (k = — [log10Ct — log10C0]/t) were calculated as a log10 reduction h‐1. Levels of copper leached from copper pipes, over a period of 24 h, ranged from 400–800 μg 1‐1. Numbers of viable MS‐2 were reduced significantly in copper pipes (k = 0.32) compared to plastic polymer pipes (k: = 0.03). New galvanized pipes showed greater inactivation of MS‐2 (k = 2.57) when compared to new copper pipes, and similar rates were also observed in the aged pipes. Poliovirus showed more resistance (k = 0.015 and 0.009 for copper and galvanized pipes, respectively) to the action of copper and galvanized pipes than MS‐2. Addition of 0.20 (μg 1‐1 free chlorine to water containing 400 (μg 1‐1 leached copper significantly enhanced the inactivation of both viruses (k = 4.74 for MS‐2 and 0.04 for poliovirus, respectively) when compared to either copper or chlorine alone. Less copper was released from aged copper pipes compared to the new ones, resulting in a significantly lower inactivation of MS‐2 (new, k = 0.32; aged, k = 0.13). The use of copper or galvanized pipes in water distribution systems may serve as an additional protection against viral contamination. 相似文献
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产H2S肠道致病性大肠埃希菌0128:K67的发现与研究 总被引:3,自引:0,他引:3
目的:对新发现的产 H2S致病性大肠埃希菌进行一系列实验研究,确认该菌在临床实践中的重要意义和流行病学价 值.方法:不同时间、不同标本中分离的产 H2S致病性大肠埃希菌,经形态学、培养特性、生化反应、血清学反应等方 法初步鉴定后,报送国家权威实验室成都生物制品研究所鉴定并命名.结果:在腹泻、食物中毒病人标本、水源水中分离的 4株产 H2S致病性大肠埃希菌,经全面鉴定后,均为 EPEC O128: k67.结论:产 H2S致病性大肠埃希菌的发现 使致病大肠埃希菌家族增加了新的成员,为微生物学研究拓展了新的领域;该菌与大肠埃希菌有密切的亲缘关系, 是变异的致泻性大肠埃希菌;因其具有较强的致病性,故应引起有关部门的高度重视并采取相应的防治对策防止该 菌造成新的腹泻病的传播和蔓延. 相似文献
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硒和维生素E对前列环素和血栓素合成的调控机制 总被引:1,自引:0,他引:1
前列环素(PGI2)和血栓素(TXA2)是一对生物功能相反的强烈的细胞生理调节剂,其生物合成是由花生四烯酸经前列腺素合酶催化生成PGH2,再在前列环素合酶和血栓素合酶的作用下分别异构为PGI2和TXA2。由于过氧化物对前列腺素合酶、前列环素合酶和血栓素合酶的催化活性有不同影响,所以能控制体内过氧化物水平的抗氧化剂硒和维生素E对PGI2和TXA2的合成具有调控作用。硒和维生素E缺乏促进PGI2/TXA2比值下降,补硒和维生素E可以纠正这种作用 相似文献
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产H2S致泻大肠埃希菌的发现与研究 总被引:5,自引:1,他引:4
[目的]对新发现的产H2S致泻大肠埃希菌进行一系列实验研究,确认该菌在临床实践中的重要意义和流行病学价值。[方法]不同时间、不同标本中分离的不同血清型的产H2S致泻大肠埃希菌,经形态学、培养特性、生化学、血清学等微生物学鉴定,初步判定后,报送国家权威实验室成都生物制品研究所鉴定并命名。[结果]在腹泻、食物中毒病人标本、水源水中分离的5株产H2S致泻大肠埃希菌,经全面鉴定后,其中4株为EPEC O128:K67,1株为ETEC O25:K19。[结论]产H2S致泻大肠埃希菌的发现使致泻大肠埃希菌家族增加了新的成员,为微生物学研究拓展了新的领域;该菌与大肠埃希菌有密切的亲缘关系,是变异的致泻大肠埃希菌;因其具有较强的致病性,故应引起有关部门的高度重视并采取相应的防治对策防止该菌造成新的腹泻病的传播和蔓延。 相似文献
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Inhibition of tumor angiogenesis in lung cancer by T4 phage surface displaying mVEGFR2 vaccine 总被引:1,自引:0,他引:1
Vascular endothelial growth factor (VEGF) has been known as a potential vasculogenic and angiogenic factor and its receptor (VEGFR2) is a major receptor to response to the angiogenic activity of VEGF. The technique that to break the immune tolerance of “self-antigens” associated with angiogenesis is an attractive approach for cancer therapy with T4 phage display system. In this experiment, mouse VEGFR2 was constructed on T4 phage nanometer-particle surface as a recombinant vaccine. T4-mVEGFR2 recombinant vaccine was identified by PCR and western blot assay. Immunotherapy with T4-mVEGFR2 was confirmed by protective immunity against Lewis lung carcinoma (LLC) in mice. The antibody against mVEGFR2 was detected by ELISPOT, ELISA and Dot ELISA. The inhibitive effects against angiogenesis were studied using CD31 and CD105 via histological analysis. VEGF-mediated endothelial cells proliferation and tube formation were inhibited in vitro by immunoglobulin induced by T4-mVEGFR2. The antitumor activity was substantiated from the adoptive transfer of the purified immunoglobulin. Antitumor activity and autoantibody production of mVEGFR2 could be neutralized by the depletion of CD4+T lymphocytes. These studies strongly suggest that T4-mVEGFR2 recombinant vaccine might be a promising antitumor approach. 相似文献
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Tung-Sheng Shih Saou-Hsing Liou Cheng-Yao Chen Thomas J. Smith 《Archives of environmental & occupational health》2013,68(1):20-25
Urinary 2-methoxy acetic acid reportedly has a long half-life (77.1 hr) in humans. The authors studied urinary 2-methoxy acetic acid in a group of 18 workers exposed to 2-methoxy ethanol from Monday to Saturday following a 7-d cease in production. The weekly time-weighted average exposure concentration of 2-methoxy ethanol was 4.5 ppm. The urinary 2-methoxy acetic acid of exposed workers was increased significantly, from 18.5 μg/ml (10.6 mg/gm creatinine) on Monday (prior to work) to 48.4 μg/ml (46.5 mg/gm creatinine) on Friday (after work), to 51.2 μg/ml (45.6 mg/gm creatinine) on Saturday after work. These levels occurred, despite that fact that the daily mean time-weighted average 2-methoxy ethanol exposures were very consistent and were close to the current Taiwan Permissible Exposure Limit of 5 ppm. These urinary 2-methoxy acetic acid levels were much higher than levels that occur with inhalation only, and they demonstrate that skin absorption is a significant contributor to 2-methoxy ethanol exposure. The high background concentrations of 2-methoxy acetic acid in the preshift urine samples following a 7-d production halt confirm that there is a long half-life of 2-methoxy acetic acid in humans. The determination of urinary 2-methoxy acetic acid is recommended for exposure assessment of 2-methoxy ethanol. 相似文献
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目的:构建新型人白细胞介素-2(125-Ser)的表达载体,并在大肠杆菌中进行表达。方法:用PCR技术对天然人IL-2基因进行突变,并与表达载体pET-11b连接,转化入大肠杆菌BL21中,用IPTG诱导表达。结果:将编码天然人IL-2的125-Cys的密码子(TGT)变成了编码125-Ser的密码子(TCT),在大肠杆菌中表达量达27%。结论构建了表达新型人IL-2(125-Ser)的表达载体,并在大肠杆菌中获得高效表达,为后续的复性和纯化工作奠定了良好的基础。 相似文献
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目的:探讨香菇多糖体外对双歧杆菌和大肠杆菌的生长影响。方法:2个麦氏浓度的双歧杆菌和大肠杆菌分别接种于PYG培养基中,12h和24h分别检测细菌数量,气相色谱法测培养24h后的细菌培养液中乙酸含量。结果:香菇多糖体外对大肠杆菌存在抑制生长的作用,对双歧杆菌有促进生长的作用,大肠杆菌对双歧杆菌的体外生长无抑制作用,双歧杆菌、双歧杆菌+香菇多糖都能够体外抑制大肠杆菌生长;在香菇多糖作用下,双歧杆菌代谢的乙酸含量与其数量呈正相关关系。结论:香菇多糖与双歧杆菌联用可以更好的对大肠杆菌发挥生物拮抗作用;主要机制是因为香菇多糖可以作为双歧杆菌的益生元,双歧杆菌增殖后乙酸代谢也随之增加,从而抑制大肠杆菌的生长。 相似文献