Diversity of tailed phages in Baltic Sea sediment: large number of siphoviruses with extremely long tails.

We present the first attempt at quantitative analysis of morphological diversity of tailed viruses obtained from marine sediments without ultracentrifugation or enrichment on specific host strains. Sandy mud samples were collected in the Gulf of Gdańsk in the spring, autumn and winter. VLPs were analyzed by transmission electron microscopy. The distribution of three groups of tailed phages was similar in all seasons (Siphoviridae: 52% on average; Myoviridae: 42%; Podoviridae: 6%). 19% of siphoviruses had prolate heads. Interestingly, 11% of siphoviral particles had tails longer than 300 nm, and 6% longer than 600 nm.