磺胺类抗生素与群体感应抑制剂对费氏弧菌的联合毒性及机制初探
发布时间：2018-09-03 19:41
【摘要】：抗生素自发现以来,因其惊人的抗菌能力,被广泛用于农业、渔业、畜牧业等领域。但是由于其大规模无节制的使用,诱导了抗性基因的产生,引发了一系列环境问题。为有效解决抗生素滥用而导致的抗性基因问题,群体感应抑制剂作为最为可能的抗生素替代品被提出。可见,抗生素与群体感应抑制剂在未来将不可避免的长期共存于环境中。因此,研究抗生素与群体感应抑制剂的慢性联合毒性,开展它们低剂量下是否存在刺激微生物生长(hormesis效应)的工作,为相关生态环境风险评价甚至医学联合用药提供理论依据,具有重要的科学意义。本文选取了12种磺胺类抗生素及三类群体感应抑制剂,以费氏弧菌为模式生物,分别测定了其15min急性单一毒性、15min急性混合毒性、24h慢性单一毒性、24h慢性混合毒性及24h慢性单一hormesis、24h慢性混合hormesis现象。通过化合物理化参数的计算、相关蛋白的同源建模、分子对接及细菌体内吲哚实验的测定,初步探讨了磺胺类抗生素与群体感应抑制剂的急慢性联合毒性作用机制及hormesis现象产生的原因。研究结果如下:(1)呋喃酮类化合物与磺胺类抗生素的二元等毒性比下的急性联合效应表现为协同与加和,吡咯酮类、吡咯类化合物与磺胺类抗生素的二元等毒性比下的急性联合效应分别表现为加和与拮抗。群体感应抑制剂的最正氢电荷的值的大小可能是其急性联合作用机制不同的原因。(2)三类群体感应抑制剂与磺胺类抗生素对费氏弧菌的慢性联合作用都表现为拮抗作用。推测其原因可能是磺胺类抗生素促进了细菌体内的Lux R蛋白的表达,而群体感应抑制剂与细菌产生的信号分子竞争结合Lux R蛋白,导致了慢性的拮抗。(3)12种磺胺在低剂量时会刺激费氏弧菌光值增大,产生hormesis效应。原因是其促进了细菌体内Lux R蛋白的表达,而Lux R蛋白是细菌发光的主要调控蛋白。通过细菌生长过程中吲哚的测定,推断吲哚并不是导致费氏弧菌Lux R蛋白表达量增加的物质,因此,hormesis现象产生的机制有待进一步的研究。(4)本研究具有hormesis效应的两种化合物混合后hormesis效应依然明显。用hormesis效应曲线与Y=0的直线所围成的闭合区间面积来评价hormesis效应。用Brain-Cousens模型将hormesis剂量-效应曲线拟合并计算闭合区间面积,建立单一hormesis面积与混合hormesis面积的相关关系方程,所建方程R2均大于0.64,说明该方程具有统计学意义,可用于混合hormesis效应的预测。
[Abstract]:Since its discovery, antibiotics have been widely used in agriculture, fishery, animal husbandry and so on. However, because of its large-scale and uncontrolled use, resistance genes are induced and a series of environmental problems are caused. In order to effectively solve the problem of resistance gene caused by antibiotic abuse, population sensing inhibitors have been proposed as the most likely substitute for antibiotics. It can be seen that antibiotics and colony-sensing inhibitors will inevitably coexist in the environment for a long time in the future. Therefore, to study the chronic joint toxicity of antibiotics and colony sensing inhibitors, and to study whether there is hormesis effect in low dose of antibiotics or not, to provide theoretical basis for ecological risk assessment and even medical combination drug use. It has important scientific significance. In this paper, 12 kinds of sulfonamides antibiotics and three kinds of population sensing inhibitors were selected, and Vibrio fernivalis was used as the model organism. The chronic mixed toxicity of 15min for 15 minutes and chronic mixed toxicity for 24 h and chronic mixed hormesis for 24 h were determined respectively. Through the calculation of physical and chemical parameters of compounds, the homology modeling of related proteins, the molecular docking and the determination of indole in bacteria, The mechanism of acute and chronic joint toxicity of sulfanilamide antibiotics and colony sensing inhibitors and the causes of hormesis phenomenon were discussed. The results are as follows: (1) the acute combined effects of furanone compounds and sulfanilamide antibiotics are synergistic and additive, pyrrolidone, pyrrolidone, The acute combined effects of pyrrole compounds and sulfanilamide antibiotics were additive and antagonistic respectively. The magnitude of the most positive hydrogen charge of the population sensing inhibitors may be the reason for the different mechanisms of their acute combination. (2) the chronic combination of three kinds of group induction inhibitors and sulfonamides against Vibrio ferrovirii showed antagonistic effects. It may be that sulfonamides promote the expression of Lux R protein in bacteria, while colony sensing inhibitors compete with the signal molecules produced by bacteria to bind Lux R protein. (3) 12 sulfonamides can stimulate the light value of Vibrio flexneri to increase at low dose and produce hormesis effect. The reason is that it promotes the expression of Lux R protein in bacteria, and Lux R protein is the main regulation protein of bacterial luminescence. Based on the determination of indole during bacterial growth, it was inferred that indole was not the substance that led to the increase of Lux R protein expression in Vibrio ferriformis. Therefore, the mechanism of hormesis needs further study. (4) the hormesis effect of the two compounds with hormesis effect is still obvious. The hormesis effect is evaluated by using the closed interval area between the hormesis effect curve and the straight line of Y _ (0). The hormesis dose-effect curve is combined with Brain-Cousens model to calculate the closed interval area, and the correlation equation between the single hormesis area and the mixed hormesis area is established. The equation R2 is larger than 0.64, which shows that the equation has statistical significance. It can be used to predict mixed hormesis effect.
【学位授予单位】：上海海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X171.5
本文编号：2220978
[Abstract]:Since its discovery, antibiotics have been widely used in agriculture, fishery, animal husbandry and so on. However, because of its large-scale and uncontrolled use, resistance genes are induced and a series of environmental problems are caused. In order to effectively solve the problem of resistance gene caused by antibiotic abuse, population sensing inhibitors have been proposed as the most likely substitute for antibiotics. It can be seen that antibiotics and colony-sensing inhibitors will inevitably coexist in the environment for a long time in the future. Therefore, to study the chronic joint toxicity of antibiotics and colony sensing inhibitors, and to study whether there is hormesis effect in low dose of antibiotics or not, to provide theoretical basis for ecological risk assessment and even medical combination drug use. It has important scientific significance. In this paper, 12 kinds of sulfonamides antibiotics and three kinds of population sensing inhibitors were selected, and Vibrio fernivalis was used as the model organism. The chronic mixed toxicity of 15min for 15 minutes and chronic mixed toxicity for 24 h and chronic mixed hormesis for 24 h were determined respectively. Through the calculation of physical and chemical parameters of compounds, the homology modeling of related proteins, the molecular docking and the determination of indole in bacteria, The mechanism of acute and chronic joint toxicity of sulfanilamide antibiotics and colony sensing inhibitors and the causes of hormesis phenomenon were discussed. The results are as follows: (1) the acute combined effects of furanone compounds and sulfanilamide antibiotics are synergistic and additive, pyrrolidone, pyrrolidone, The acute combined effects of pyrrole compounds and sulfanilamide antibiotics were additive and antagonistic respectively. The magnitude of the most positive hydrogen charge of the population sensing inhibitors may be the reason for the different mechanisms of their acute combination. (2) the chronic combination of three kinds of group induction inhibitors and sulfonamides against Vibrio ferrovirii showed antagonistic effects. It may be that sulfonamides promote the expression of Lux R protein in bacteria, while colony sensing inhibitors compete with the signal molecules produced by bacteria to bind Lux R protein. (3) 12 sulfonamides can stimulate the light value of Vibrio flexneri to increase at low dose and produce hormesis effect. The reason is that it promotes the expression of Lux R protein in bacteria, and Lux R protein is the main regulation protein of bacterial luminescence. Based on the determination of indole during bacterial growth, it was inferred that indole was not the substance that led to the increase of Lux R protein expression in Vibrio ferriformis. Therefore, the mechanism of hormesis needs further study. (4) the hormesis effect of the two compounds with hormesis effect is still obvious. The hormesis effect is evaluated by using the closed interval area between the hormesis effect curve and the straight line of Y _ (0). The hormesis dose-effect curve is combined with Brain-Cousens model to calculate the closed interval area, and the correlation equation between the single hormesis area and the mixed hormesis area is established. The equation R2 is larger than 0.64, which shows that the equation has statistical significance. It can be used to predict mixed hormesis effect.
【学位授予单位】：上海海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X171.5
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