MOLECULAR AND BIOCHEMICAL-STUDIES OF VIRUS-INFECTIONS IN 2 FILAMENTOUS BROWN-ALGAE

The filamentous marine brown algae Ectocarpus siliculosus and Feldmann ia simplex are infected by host specific DNA-viruses. Under Percoll is olation, Ectocarpus siliculosus-virus (EsV)-particles maintained their infective potential. The EsV has a circular genome of dsDNA with a si ze of 320 kb. A restriction map has been established. The gene of a ma jor coat protein (gp1) was detected in a genomic library and partly se quenced. Using gp1-sequences for polymerase chain reaction (PCR) ampli fication analysis, EsV-specific sequences could be detected in various symptom-free, clonal cultures of Ectocarpus. The PCR was also used to follow the passage of the virus genome during the meiosis of hosts. A monospecific antibody against recombinant gp1 was used for immunostai ning and infection experiments. The Feldmannia simplex-virus (FlexV-1) has a circular genome with a size of 220 kb and a 43% G+C content. Fs V-DNA contains methylated bases. 5-methylcytosine (5 mC) makes up 12% of the total cytosines.