乙醇对简单节杆菌生长和细胞形态的影响

发布时间：2018-04-19 09:06

本文选题：细胞形态 + 简单节杆菌　；参考：《天津科技大学》2012年硕士论文

【摘要】：微生物的有机溶剂耐性机制非常复杂,具有明显的菌种特异性和溶剂选择性,本论文以甾体C1,2脱氢反应菌种-简单节杆菌(Arthrobacter simplex)为研究模型,系统研究了有机溶剂对微生物细胞形态的影响。首先,通过传统紫外诱变结合高浓度乙醇驯化的方法,选育得到乙醇耐受性突变株TCCC11037-UV15X1-2,该菌株在乙醇浓度10%(v/v)时仍表现出一定的生长活性,并具有良好的遗传稳定性。出发菌株和耐性突变株均能利用乙醇作为唯一碳源生长,且耐性突变株表现出更高的乙醇利用能力,乙醇浓度为6%时菌体仍表现出良好的生长。乙醇培养初期添加对耐性突变株和出发菌株生长均产生了一定的抑制作用,且对出发菌株的抑制作用更为显著。随着乙醇浓度的增加,最大细胞浓度和比生长速率均显著降低,乙醇浓度为6%时分别为对照组的51.86%和21.90%,耐性突变株在乙醇添加浓度为2%时表现出的生长特性,最大细胞浓度和比生长速率分别0.822和0.106h-1,与未添加乙醇的对照组的0.732和0.108h-1相比几乎相同。当乙醇浓度为8%时耐性突变株延滞期延长,但之后又显示出一定的生长；乙醇对数中后期添加时,出发菌株的生长明显受到抑制,并随乙醇浓度的增加抑制作用逐渐增强。对于耐性突变株,乙醇浓度在2%-4%范围内,菌体生物量均呈现较明显的增长趋势。与出发菌株相比,耐性突变株具有一定的乙醇耐受性,且在4%浓度范围内乙醇对耐性突变株的生长存在促进作用。对于出发菌株,对数中后期添加不同浓度的乙醇,在乙醇浓度0-6%的的范围内,细胞的比表面积随着乙醇浓度的增加不断减小,最小减至8.334(对照组为10.527),并表现出明显的剂量依赖性。当乙醇压力移除后,菌体的细胞形态能够可逆回复。说明细胞形态通过降低与有机溶剂的接触面积而表现出一定的适应性,这种变化由乙醇诱导产生。而对于耐性突变株,未添加乙醇时细胞的比表面积为8.661,明显小于出发菌株(10.527),说明耐性菌株通过减小其比表面积降低与溶剂的接触面积,抵御乙醇对菌体的不利影响。并且其细胞比表面积不会随着乙醇浓度的改变和乙醇的撤除发生明显变化,说明耐性突变的细胞形态已经发生了一种较为稳定、长期的变化。静息体系下乙醇对细胞形态的研究表明,细胞形态对有机溶剂作出的响应能够在较短时间内完成,乙醇处理3h和24h后细胞表面积和比表面积没有明显波动。此外,静息体系下细胞形态的变化与有机溶剂的浓度没有明显的剂量依赖关系。
[Abstract]:The mechanism of organic solvent tolerance of microbes is very complex, with obvious strain specificity and solvent selectivity. In this paper, Arthrobacter simplexer, a steroidal C _ 1O _ 2 dehydrogenation reaction strain, was used as the research model.The effects of organic solvents on the morphology of microorganism were systematically studied.Firstly, the ethanol tolerant mutant TCCC11037-UV15X1-2 was obtained by traditional ultraviolet mutagenesis combined with high concentration ethanol acclimation. TCCC11037-UV15X1-2 still showed certain growth activity and good genetic stability when ethanol concentration was 10g / v.Both the original strain and the tolerant mutant could grow with ethanol as the sole carbon source, and the tolerant mutant showed higher ethanol utilization ability, and the bacteria still showed good growth when ethanol concentration was 6.In the early stage of ethanol culture, the growth of resistant mutants and parent strains was inhibited by adding ethanol, and the inhibitory effect on the original strain was more significant.With the increase of ethanol concentration, the maximum cell concentration and specific growth rate decreased significantly. When ethanol concentration was 6, it was 51.86% and 21.90% of the control group, respectively.The maximum cell concentration and specific growth rate were 0.822 and 0.106 h-1 respectively, which were almost the same as 0.732 and 0.108h-1 in the control group without ethanol.When the ethanol concentration was 8, the delay period of tolerant mutant was prolonged, but the growth of the mutant was shown to be certain. When the ethanol concentration was added in the middle and late period of ethanol, the growth of the original strain was obviously inhibited, and the inhibitory effect was gradually enhanced with the increase of ethanol concentration.For tolerant mutants, the biomass of bacteria increased significantly in the range of 2% -4% ethanol concentration.Compared with the original strain, the tolerant mutant had certain ethanol tolerance, and ethanol promoted the growth of the tolerant mutant in the range of 4%.For the original strain, the specific surface area of the cells decreased with the increase of ethanol concentration in the range of 0-6% ethanol concentration, when different concentrations of ethanol were added in the late logarithmic period.The minimum was reduced to 8.334 (the control group was 10.527) and showed a significant dose dependence.When the ethanol pressure was removed, the cell morphology was reversible.The results showed that the cell morphology showed adaptability by decreasing the contact area with organic solvents, which was induced by ethanol.For tolerant mutants, the specific surface area of the cells without ethanol was 8.661, which was significantly smaller than that of the original strain (10.527), which indicated that the resistant strain could resist the adverse effect of ethanol on the bacteria by reducing its specific surface area and reducing the contact area with the solvent.The specific surface area of the cells did not change obviously with the change of ethanol concentration and ethanol removal, which indicated that the cell morphology of tolerant mutation had been changed steadily and for a long time.The study of ethanol on cell morphology in resting system showed that the response of cell morphology to organic solvent could be completed in a relatively short time, and there was no obvious fluctuation of cell surface area and specific surface area after ethanol treatment for 3 h and 24 h.In addition, there was no significant dose-dependent relationship between the changes of cell morphology and the concentration of organic solvents in the resting system.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R378

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