The RNAs extracted from 28 high spin pellets of clarified lysates from
BGM cells, previously infected by concentrated Adriatic Sea water sam
ples, were analyzed by a dot blot test. We used a P-32-labeled cDNA pr
obe (BamHI220-670) from the 5' non-coding end of the cloned poliovirus
1 (Mahoney) genome. The probe was selected for its broad range of gen
etic specificities. Based on the density of the hybridization signals
on the autoradiograph, our dot blot results showed a high degree of re
activity of the probe to homologous (poliovirus 1) and heterologous (e
chovirus 6 and coxsackievirus B3) reference RNA, as predicted by a com
puter analysis of their sequences, and a low reactivity to that of the
samples leading us to exclude the presence of enteroviruses like the
reference strains. In order to understand if there were other enterovi
ral serotypes or not, dot blot tests were supplemented with Northern-b
lot hybridization assays. Results from the Northern-blot showed a seri
es of fragments ranging from 4.3 to 1.2 kb but no signal corresponding
to 7.5 kb (as did the positive control RNAs). These features suggeste
d that the tested RNAs might derive from viruses of the Reoviridae fam
ily, which includes members with segmented genome. Traditional PAGE an
alysis showed clearly the 10-fragments pattern characteristic of reovi
ruse. Twenty-three out of the twenty-eight samples tested showed the p
resence of viruses, and this confirms the previously noted cytopathic
effect (CPF) of the samples on the BGM cells.