The Study Of Adsorption Rate And Stability Of Cyanophage PP

Cyanophage "PP" was the first freshwater cyanophage isolated in China by our lab and infected Plectonema boryanum IU594 and Phormidium foveolarum IU427. More detailed studies on its physiology were performed and the results were obtained as follows:The stability of cyanophage PP after conserved in five liquids showed gradually decreasing pattern in order as: common AA culture medium, common AA culture medium and PO43- free, common AA culture medium and NOs" free, common AA culture medium and Mg2+ free, distilled water. The results reflected the indispensable of Mg2+ for maintaining the stability of cyanophage PP.Results involved in the adsorption of cyanophage PP showed: 1. Divalent positive ion such as Mg2+, Ca2+ and Fe2+ were not necessary to the adsorption of cyanophage PP though it was favored by Ca2+ and Fe2 at 10mM. 2.The adsorption rate was affected by both PP and its host with regard to concentration. When the concentration of host cells was lower than 106 cell·mL-1, the adsorption rate tended to be low and presented itself more obvious in the case of higher concentration of the cyanophage than that of the host cells. In contrast, when the concentration of host cells was higher than 106 cell·mL-1 the result was just opposite. 3.With the increase in multiply of PP and host cells concentration, the adsorption rate was tend to rise.The changes in adsorption rate of PP by P. 5 94 in different growth stages and under various nutrition conditions were outlined as below: 1. Nitrogen and phosphate in different concentrations had no obvious effect on the adsorption , rather, the adsorption rate was affected by P.594 in different growth phrases, for example the adsorption rate in stationary phrase was much lower than that in log and decline phrase. 2. The latent period of PP was observed to be longer when nitrogen and phosphate were in high concentration. Oppositely, the latent period was short when host cell was old.The activity of cyanophage PP was influenced by both ultraviolet radiation (UV) at different wave lengths and sunlight radiation. For example, the inactivation by UVB was much greater than that by UVA, and the day inactivation in summer was much higher than that in winter.Evidently, photoreaction of PP occurred after PP radiated by UVA and UVB. Moreover, the photoreaction rate was affected by some factors such as UV radiation time, photoreaction time and growth state of host cells, etc. The longer the radiation time, the lower the photoreaction rate. On the contrary, the longer the photoreaction time, the higher the photoreaction rate. However, there existed a saturation phenomenon. In addition, the photoreaction ability showed weak tendency with the ageing of host cells.