FORMATION OF SUBMICRON COLLOIDAL PARTICLES FROM MARINE-BACTERIA BY VIRAL-INFECTION

We tested the hypothesis that viral lytic infection leads to the forma tion of submicron-sized colloidal particles originating from marine ba cteria. Laboratory experiments were performed using a marine bacterium , Vibrio alginolyticus, and and its infectious phage. A particle count er was used to determine abundance and size distribution of particles. We found that the non-living submicron sized particles (size range fr om 0.38 to 0.7 mu m in diameter) increased rapidly along with a decrea se of bacteria and an increase of phage, indicating that these particl es are cell debris originating from bacteria. These particles were sta ined faintly by acridine orange but were not countable due to the amor phous shape. These results show that amorphous submicron particles are produced by viral lysis of bacteria. This process maybe one of the ma jor pathways of colloid formation associated with microbial food webs in the sea.