MEDIEVAL WALL PAINTINGS - A HABITAT FOR ARCHAEA - IDENTIFICATION OF ARCHAEA BY DENATURING GRADIENT GEL-ELECTROPHORESIS (DGGE) OF PCR-AMPLIFIED GENE FRAGMENTS CODING FOR 16S RIBOSOMAL-RNA IN A MEDIEVAL WALL PAINTING

This report describes the detection and identification of archaea in a deteriorated medieval wall painting from the 13th century by denaturi ng gradient gel electrophoresis (DGGE) of PCR-amplified DNA encoding 1 6S rRNA without prior cultivation of the organisms. Total DNA was extr acted from wall painting material and 547 bp fragments of the 16S rDNA were amplified with archaeal specific primers. Six out of ten analyze d samples showed the presence of archaeal 16S rDNA fragments. The PCR products of uniform length presumably obtained from different archaea species were separated according to their sequence differences by DGGE to visualize the diversity of the archaeal community within the wall painting material. By sequencing an individual DNA band and comparing the data with known 16S rRNA sequences, the corresponding bacteria wer e identified as members or close relatives of the genus Halobacterium. The results suggest that archaea and, in particular, extremely haloph ilic species might be more widely involved in deterioration and discol ouration processes than commonly recognized. (C) 1998 Elsevier Science Ltd. All rights reserved.