【作者】 罗文清；

【导师】 赵以军；

【作者基本信息】 华中师范大学 ， 微生物， 2004， 硕士

【摘要】 浓缩是研究噬藻体的重要前期工作，我们以本实验室分离的淡水噬藻体PP为实验材料，结合超滤技术，建立了一套能够有效浓缩水样中噬藻体的方法---反冲超滤法。此浓缩技术可使噬藻体的回收率达90％以上，浓缩倍数达30倍。此法也适用于大量水样的处理，而且当采用两步反冲超滤技术时，噬藻体的浓缩倍数可以提升到近100倍。 以噬藻体PP为对象运用正交设计的实验方法，我们还研究了几种环境因子对噬藻体增殖的影响，结果如下： 在测定吸附率的实验中，我们发现温度是主要的影响因素，并且在统计学上有显著意义。随着温度的提高，饱和吸附率呈不断上升的趋势，达到饱和吸附率的时间也不断延长；与温度相比，光照是次要的影响因素，随着光照强度的增加，噬藻体对宿主藻的吸附速度不断提高，饱和吸附率不断上升，达到饱和吸附的时间也不断延长。并且，发现当温度和光照分别为28℃和2000Lux时，吸附率达到最大值为62.4％。 测定释放量和潜伏期的实验结果表明，温度和光照是主要的影响因子，在无光照或温度较低的情况下，噬藻体几乎不增殖。随着温度的升高和光照的增强，噬藻体的释放量会逐渐增大，而潜伏期却随温度的升高会逐渐地缩短，不过增加光照强度对潜伏期长短的影响并不大。宿主生长期和N、P浓度对释放量和潜伏期也有一定的影响。我们发现，在N、P浓度分别为2mM和0.2mM的培养基中，当宿主处于延迟生长期，感染温度、光照分别为28℃和2000 Lux时，噬藻体有最大释放量，为135 PFU·cell^-1。 根据有关噬藻体PP生理学实验的结果，我们采用逐步判别回归方法，初步建立了自然环境中噬藻体PP种群大小变化的动态平衡方程： N（t）=N（t-1）+N（t-n）^*Y（A）^*[Y（B）-1]^*dt-N（t）^*Y（C）^*dt+Y(D_t-1)更多还原

【Abstract】 Concentration is the important prophase step for studying cyanophage. A new concentration system, the backflushing ultrafiltration system , was constructed with the isolated cyanophage PP in our lab associated with the ultrafiltration technique.Basing on this system, the cyanophage concentration multiple could reach up to 30 times and the recovery rate of the cyanophage could exceed 90%. This method was also effective for concentrating virus form large volume water samples. Moreover/the concertration multiple of cyanophage PP could rise to nearly one-hundred times when two-step backflushing ultrafiltration technique was adopted.Again,using cyanophage PP and adopting orthogonal design ,we have \ performed the studies on the effects of several environmental factors on the multiplication of the cyanophage. Results are as follows:In the experiment of measuring the adsorption rate,temperature was found to be the primary influencing factor and displayed an obvious significance by the statistics analysis. As temperature rose, the saturated adsorption rate tended to increase ,and the time to reach saturation would become longer. Comparatively, the sunlight radiation showed a minor influence. With the intensity of sunlight radiation strengthened, the adsorption speed of the cyanophage to the host gradually quickened, and reached the maximum of 62.4% at 28Cand 2000 Lux.Results involved in measuring burst size and latent period of the cyanophage showed that both temperature and sunlight are the important effect factors. Under the dark condition or at low temperatures, the cyanophage wouldn’t multiply, but the elevation in both temperature and sunlight would bring about the burst size to increase. The rising temperature would lead the latent period to shorten, though the increasing sunlight intensity did not show much influence. In comparision with temperature and sunlight, the level of N and P concentration as well as the growth phase of the host represented the subordinate effect factors for the multiplicationof cyanophage. In our experiment at 28C and 2000 Lux ,it gave rise to the maximal burst size of 135 PFU cell-1 for cyanophage PP ,when it infected the lag phase host only grown in 2mM N and 0.2mM P medium.Furthermore, by adopting the experimental data and stepwise discriminant analysis,we established the preparatory dynamic balance equation for the change in the population of cyanophage PP in the natural environment as follows: N(t)=N(t-1)+N(t-n)* Y(A)* [ Y(B)-1 ] *dt-N(t)* Y(C)*dt+Y(Dt-1)更多还原