厌氧水环境中噬菌体MS2的存活和团聚特性及理化因素的影响

为探究病毒在厌氧水环境中的存活特性,以噬菌体MS2为模式病毒,采用双层平板法进行噬菌体MS2的定量检测,研究温度、pH值、悬浮颗粒物、乙酸等理化条件对噬菌体MS2的影响,分析其衰减动力学特征,并通过测定Zeta电位和噬菌斑直径考察噬菌体颗粒在不同条件下的聚集状况.结果表明,在厌氧水环境中,噬菌体MS2的衰减符合一阶指数衰减模型.在众多研究因素中,温度是影响噬菌体MS2存活的最主要因素.噬菌体MS2在4,17,25和35℃时的T₉₀分别为20.36,6.14,5.15和0.46d.35℃条件下12h后噬菌体失活率高达2.44lg,而4℃条件下7d后噬菌体失活率仅有0.78lg.增加乙酸浓度能明显提高噬菌体MS2的衰减速率.低pH值和悬浮颗粒物条件会促进噬菌体的团聚,使噬菌体颗粒Zeta电位降低,水力学直径增大,但悬浮颗粒物浓度过高会影响颗粒间的静电作用.噬菌体的团聚也增加了噬菌斑的直径,pH=6和20mg/L的悬浮颗粒物条件下,直径1.0mm以上的大噬菌斑数量占比分别达到了45.61%和57.74%.明确厌氧水环境中各种理化因素对噬菌体MS2的影响,可为水环境病毒控制提供科学依据.

Survival and aggregation characteristics of bacteriophage MS2 in anaerobic water environment and influence of physicochemical factors

Bacteriophage MS2 was chosen as the model virus to reveal the survival characteristics of virus in anaerobic water environment. The effect of physicochemical conditions, including temperature, pH, suspended particles, and acetic acid on bacteriophage MS2 were studied by double-layer plate method. The decay kinetics of bacteriophage MS2 were analyzed, and the aggregation of phage particles under different conditions was investigated by measuring Zeta potential and plaque diameter. The results showed that the decay of bacteriophage MS2 in anaerobic water environment followed the first-order exponential decay model. Among the above-mentioned factors, temperature was the most important factor affecting the survival of bacteriophage MS2. At 4℃, 17℃, 25℃ and 35℃, the T₉₀ values of bacteriophage MS2 were 20.36d, 6.14d, 5.15d and 0.46d, respectively. The inactivation rate of bacteriophage MS2 was as high as 2.44lg after 12h at 35℃, while the inactivation rate was only 0.78lg after 7days at 4℃. Increasing the concentration of acetic acid significantly enhanced the inactivation rate of bacteriophage MS2. Low pH value and suspended particles promoted the aggregation of bacteriophage MS2, which caused Zeta potential decrease and the hydrodynamic diameter of phage particles increase, but excessively high concentrations of suspended particles affected the electrostatic interaction between particles. The aggregation of bacteriophage MS2 also increased the diameter of plaques. Under the condition of pH 6 and suspended particles at 20mg/L, the proportion of large plaques with diameter more than 1.0mm reached 45.61% and 57.74%, respectively. Clarification of the impact of various physicochemical factors on bacteriophage MS2 in anaerobic water environment can provide scientific basis for virus control in water environment.