The gene fucA1 is expressed in S.solfataricus at very low level under the conditions tested. In particular, the transcriptional analysis of the gene revealed that it is expressed at very low level in both YSM and YGM media. Similarly, no differences in the two media could be found by western blot probed with anti-Ssa-fuc antibodies, indicating that the low expression of the enzyme in S.solfataricus is the result of scarce transcription rather than suppressed translation.