Sequence analysis of bacterial DNA in the colon and stomach of the Tyrolean Iceman

The male human body found in an Alpine glacier on September 19, 1991 ("Tyrolean Iceman") has, for the first time in history, given scientists a chance to perform detailed anatomical, histological, and molecular investigations on the organs of a person from the Neolithic Age (5350-5100 B.P.). In the present study, tissue samples aseptically taken from the stomach and the colon of the mummy were utilized for DNA extraction, and the DNA was PCR-amplified, using primer pairs designed to bind to fragments of the 16s ribosomal RNA gene (16s rDNA) of a broad range of bacteria. The PCR products were cloned in plasmid vectors, and the recombinant clones (amplicons) were sequenced. The sequence data were finally used for scanning data libraries containing the corresponding sequences of present-day bacteria, to infer the putative ecophysiology of the ancient ones. The same procedure was repeated on some fragments of grass from the clothing found near the corpse. These fragments were taken as a control of the microbiological situation of the glacier. The results show that the flora of the Iceman's stomach is entirely composed of Burkholderia pickettii, an organism commonly found in aquatic habitats. The colon, on the other hand, contains several members of the fecal flora of humans, such as Clostridium perfringens, C. ghonii, C. sordellii, Eubacterium tenue, and Bacteroides sp. The Iceman's colon, however, was found to contain, rather unexpectedly, also some members of the genus Vibrio. The results are discussed in light of what is known about the preservation of microbial DNA at the Iceman's site and of previous parasitological studies performed on the Iceman himself and on human coprolites.     

Sequence analysis of bacterial DNA in the colon of an Andean mummy

We have isolated DNA from 14 tissue samples from the internal organs of an Andean human mummy (10th–11th century A.D.) and have checked the persistence of the original human and bacterial templates using the following main approaches: 1) amino acid racemization test; 2) quantification of mitochondrial DNA copy number; 3) survey of bacterial DNA in the different organs; 4) sequence analysis of bacterial amplicons of different lengths. The results demonstrate that both the original human DNA and the DNA of the bacteria of the mummy gut are preserved. In particular, sequence analysis of two (respectively 100 and 196 bp in length) libraries of bacterial 16s ribosomal RNA gene amplicons from the mummy colon shows that while the shortest amplicons give only modest and biased indications about the bacterial taxa, the longer amplicons allow the identification several species of the genus Clostridium which are typical of the human colon. This work represents a first example of a methodological approach which is applicable, in principle, to many other natural and artificial mummies and might open the way to the study of the structure of the human microbial ecosystem from prehistory to present. Am J Phys Anthropol 107:285–295, 1998. © 1998 Wiley-Liss, Inc.     

Fatty acid profile and proximate composition of fillets from Engraulis encrasicholus,Mullus barbatus,Merluccius merluccius and Sarda sarda caught in Tyrrhenian,Adriatic and Ionian seas

The study examined the proximate composition, cholesterol content and fatty acid profile of fillet from the most important species captured in Italian seas and commonly consumed in the European Union, such as anchovy (Engraulis encrasicholus L.), red mullet (Mullus barbatus L.), European hake (Merluccius merluccius L.) and Atlantic bonito (Sarda sarda L.). The fish were caught in three different geographic areas of the Italian seas: south Tyrrhenian (ST), south Adriatic (SA) and Ionian (IO). Anchovy from the ST sea had the highest lipid content (2.27%) compared to fish captured in the SA (1.81%) and IO seas (1.91%) (P < 0.01). Red mullet captured in the SA exhibited the highest amount of lipid content (7.54%) compared to fish from the ST (1.82%) and IO seas (3.23%) (P < 0.01). The total cholesterol content of fish did not show significant differences from one geographic area to the other, particularly for European hake (from 98 to 66 mg per 100 g). The fatty acid profile of anchovy species was not affected by the geographical capture area. European hake caught in the ST sea showed the highest proportion of DHA (29.13%) in comparison to those captured in the SA (19.98%) and IO seas (19.84%). Atlantic bonito from the ST had the highest proportions of DHA (24.94%), compared to those from the SA (12.08%) and IO seas (13.83%). The SA bonitos contained a significantly lower proportion of EPA (3.31%) in comparison to fish from both the ST and IO seas (5.66 and 5.17%, respectively). Red mullet captured in the ST exhibited the highest proportions of DHA, n‐3 PUFA, and total PUFA, and significantly lower proportions of oleic acid and MUFA. The fish from the ST sea showed better nutritional traits than those from other geographical areas although they all had excellent nutritional traits due to the low fat content and very high n‐3 PUFA proportion.     

Ancient microorganisms offer new clues to the Iceman’s mummification

The DNA identification of the microorganisms that colonized the so-called Tyrolean Iceman in the ancient times can offer a clue to understanding the exact process through which the natural mummification of the 5.100–5.300 year-old body took place. The results suggest that this process was considerably more complex than previously assumed (wind desiccation followed by freezing) possibly involving also a prolonged stage of water immersion of the corpse.     

DNA decay rate in papyri and human remains from Egyptian archaeological sites

The writing sheets made with strips from the stem (caulis) of papyri (Cyperus papyrus) are one of the most ingenious products of ancient technology. We extracted DNA from samples of modern papyri varying in age from 0-100 years BP and from ancient specimens from Egypt, with an age-span from 1,300-3,200 years BP. The copy number of the plant chloroplast DNA in the sheets was determined using a competitive PCR system designed on the basis of a short (90 bp) tract of the chloroplast's ribulose bisphosphate carboxylase large subunit (rbcL) gene sequence. The results allowed us to establish that the DNA half-life in papyri is about 19-24 years. This means that the last DNA fragments will vanish within no more than 532-672 years from the sheets being manufactured. In a parallel investigation, we checked the archaeological specimens for the presence of residual DNA and determined the extent of racemization of aspartic (Asp) acid in both modern and ancient specimens, as a previous report (Poinar et al. [1996], Science 272:864-866) showed that racemization of aspartic acid and DNA decay are linked. The results confirmed the complete loss of authentic DNA, even in the less ancient (8th century AD) papyri. On the other hand, when the regression for Asp racemization rates in papyri was compared with that for human and animal remains from Egyptian archaeological sites, it proved, quite surprisingly, that the regressions are virtually identical. Our study provides an indirect argument against the reliability of claims about the recovery of authentic DNA from Egyptian mummies and bone remains.