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为研究丁香酚对多重耐药大肠杆菌(Multidrug-resistant Escherichia coli,MDR E.coli)的抑菌活性,利用微量二倍稀释法和琼脂扩散法确定丁香酚对多重耐药大肠杆菌的最低抑菌浓度(Minimum inhibitory concentration,MIC)和最低杀菌浓度(Minimum bactericidal concentration,MBC),并利用紫外分光光度法、考马斯亮蓝法等方法初步分析其作用机制。结果表明,丁香酚对MDR E.coli的MIC和MBC分别为2.50 mg/mL和5.00 mg/mL;丁香酚可延长MDR E.coli迟缓期进入对数生长期的进程,改变菌体结构,增加菌株可溶性蛋白的含量和胞外核酸的量,增大菌体培养液中的电导率,对MDR E.coli具有较强的抑菌作用,这些作用可能归因于丁香酚对其细胞结构的破坏。本研究为临床有效缓解或解决多重耐药大肠杆菌的耐药、感染和致死率等问题提供新的思路、新途径,并为其在医药和食品开发领域的应用奠定理论基础。 相似文献
44.
焙烤食品种类繁多、营养丰富,不仅容易氧化变质,更容易滋生霉菌,导致产品变质.本实验主要分为两部分:首先,分离、纯化几种发霉焙烤制品上的特征菌,通过形态观察,初步鉴定为青霉菌和曲霉菌;然后使用天然肉桂、丁香精油作为防腐剂,通过测定固相/气相抑菌圈和MIC来研究精油对霉菌的抑制作用.结果表明,肉桂、丁香精油对霉菌具有显著的抑制效果,可作为天然防腐荆应用于焙烤制品,达到抑菌、防腐和延长焙烤制品货架期的目的. 相似文献
45.
几种中草药提取液对沙门氏菌抑菌效果研究 总被引:2,自引:0,他引:2
用醇提和水煎两种方法从30种中草药中筛选抑菌作用显著的4种材料为鹿蹄草、山豆根、石榴皮、五倍子。用二倍稀释法测定测定这4种中草药对沙门氏菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),然后进一步研究其对温度、介质pH、紫外线照射的稳定性。结果表明:鹿蹄草最小抑菌浓度(MIC)为125mg/mL,最小杀菌浓度(MBC)为250mg/mL,五倍子和石榴皮MIC为62.5mg/mL,MBC为125mg/mL,山豆根MIC为250mg/mL,MBC为500mg/mL。温度、介质pH、紫外线照射对这4种中草药提取液稳定性有一定影响。 相似文献
46.
Hanene Jrah Harzallah Bochra Kouidhi Guido Flamini Amina Bakhrouf Touhami Mahjoub 《Food chemistry》2011
We investigate in this work the chemical composition by GC–EIMS, the antibacterial and the cytotoxic activities of Tunisian Nigella sativa essential oil and its bioactive compound, thymoquinone, were tested against various clinical cariogenic bacteria (n = 30). Eighty-four compounds were identified in the essential oil. The major one was p-cymene (49.48%) whereas thymoquinone represented only 0.79%. The essential oil (2.43 mg/disc) containing only 3.35 μg of thymoquinone showed pronounced dose dependant antibacterial activity against Streptococcus mitis, Streptococcus mutans, Streptococcus constellatus and Gemella haemolysans (15.5 ± 0.707 mm). However, pure thymoquinone compound (150 μg/disk) was active against all the studied strains especially S. mutans and S. mitis (24.5 ± 0.71 and 22 ± 1.41 mm inhibition zones, respectively). 相似文献
47.
An in vitro study on the dental caries preventing effect of oligomeric procyanidins in sorghum episperm 总被引:1,自引:0,他引:1
Procyanidins are abundant in sorghum episperm. In this study, the effects of procyanidins from Sorghum bicolor (L.) moench episperm (sorghum procyanidins, SPC) in preventing dental caries were investigated through analysis on SPCs’ effects on cariogenic bacteria and ability in scavenging superoxide anion free radicals. In addition, the SPC with activity in preventing dental caries were identified. The ESI-MS/MS analysis results revealed that the compositions of SPC purified by macroporous resin were dimmers, trimers, tetramers, pentamers and hexamers of procyanidins and catechin/epicatechin monomers. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of SPC on Streptococcus mutans (Ingbritt C) and Streptococcus sobrinus 6715 were 8 and 16 mg/ml, respectively. The SPC had a remarkable inhibition effect (P < 0.05) on acid production of S. sobrinus (Ingbritt C) and S. mutans 6715 compared with the control group, and a dose-dependent relationship was observed. By increasing the concentration of SPC in the experimental condition (200–600 mg/L), the scavenging ratio of superoxide anion radicals increased significantly, indicating that SPC could be used as a potential dental-caries-preventative medicine with its antibacterial and antioxidant ability. 相似文献
48.
J. Côté S. Caillet D. Dussault J.-F. Sylvain M. Lacroix 《Food research international (Ottawa, Ont.)》2011,44(9):2922-2929
The effects of the industrial juice process on the ability of neutralized cranberry samples and extracts (polar, apolar and anthocyanins) to inhibit the growth of Enterococcus faecium resistant to vancomycin (ERV), Escherichia coli O157:H7 EDL 933, E. coli ATCC 25922, Listeria monocytogenes HPB 2812, Pseudomonas aeruginosa ATCC 15442, Salmonella Typhimurium SL1344 and Staphylococcus aureus ATCC 29213 were investigated. The juice process appeared to have a general enhancing effect on the antibacterial properties of cranberry polar and anthocyanin extracts. The lowest minimum inhibitory concentrations (MICs) (1.80–7.0 μg phenol/well) were obtained when S. aureus, S. Typhimurium, and ERV were exposed to the juice concentrate. The growth of P. aeruginosa, L. monocytogenes, E. coli ATCC, and E. coli O157:H7 was not inhibited by the juice concentrate, but did show sensitivity (maximal tolerated concentrations of 0.007–0.4 μg phenol/well). The lowest MICs (22.6–90.5 μg phenol/well) for P. aeruginosa, S. aureus, S. Typhimurium, and ERV were observed when they were exposed to the cranberry anthocyanin extract obtained from cranberry pomace. The results also showed a negative effect of the juice process on the antibacterial properties of the cranberry apolar extracts: the one obtained from frozen cranberries was most efficient against P. aeruginosa, S. aureus, L. monocytogenes and S. Typhimirium (MIC of 45.50 μg phenol/well). The tested bacteria showed the greatest resistance toward the cranberry extracts obtained from the mash and the macerated and depectinized mash. 相似文献
49.
探索常见金属离子掺杂对抑菌片的抑菌性能的影响,为新型纳米TiO2抑菌片的制备与改善提供技术基础。选择固定质量分数的Ag+、Zn2+和Fe3+掺杂TiO2,通过抑菌圈、MIC与MBC方法综合评价其抑菌性能,对微观结构进行表征分析,探讨抑菌性能差异的原因。结果表明:抑菌性能大小顺序为Ag@TiO2> Zn@TiO2> Fe@TiO2,Zn@TiO2 的抑菌活性较好但抑菌稳定性差Ag@TiO2对大肠杆菌和金黄色葡萄球菌的MIC、MBC均是10、20 mg/L,Zn@TiO2对大肠杆菌和金黄色葡萄球菌的MIC、MBC均是30、50 mg/L。表征发现抑菌活性强弱主要归因于纳米TiO2表面与金属离子共同产生的活性位点数量及稳定性,与孔结构或表面宫能团的关联不大。 相似文献
50.
Nina Wurzler Jan D. Schutter Ralph Wagner Matthias Dimper Vasile-Dan Hodoroaba Dirk Lützenkirchen-Hecht Ozlem Ozcan 《工业材料与腐蚀》2021,72(6):983-994
Biofilm formation and microbially influenced corrosion of the iron-reducing microorganism Shewanella putrefaciens were investigated on stainless steel surfaces preconditioned in the absence and presence of flavin molecules by means of XANES (X-ray absorption near-edge structure) analysis and electrochemical methods. The results indicate that biofilm formation was promoted on samples preconditioned in electrolytes containing minute amounts of flavins. On the basis of the XANES results, the corrosion processes are controlled by the iron-rich outer layer of the passive film. Biofilm formation resulted in a cathodic shift of the open circuit potential and a protective effect in terms of pitting corrosion. The samples preconditioned in the absence of flavins have shown delayed pitting and the samples preconditioned in the presence of flavins did not show any pitting in a window of −0.3- to +0.0-V overpotential in the bacterial medium. The results indicate that changes in the passive film chemistry induced by the presence of minute amounts of flavins during a mild anodic polarization can change the susceptibility of stainless steel surfaces to microbially influenced corrosion. 相似文献