Freezing at -800 degrees C distorts the DNA composition of bacterial communities in intestinal samples.
Terminal-restriction fragment length polymorphism (T-RFLP) was used to evaluate how to store intestinal specimens for bacterial community analysis. Bacterial communities are increasingly often described by means of DNA-based methods and it is common practice to store intestinal or faecal specimens either at -20 degrees C or -80 degrees C. In this study, samples of intestines from five different pigs were stored at -80 degrees C and -20 degrees C, respectively and a thawing and freezing procedure was carried out three times for each intestinal per pig per temperature. The cumulative sum of the T-RFLP peak heights (T-RF intensities) decreased as the temperature decreased. The composition of the bacterial community changed when stored at -80 degrees C compared to the samples stored at -20 degrees C. Thus it is recommended from this study that samples of intestinal content are stored at -20 degrees C before use for bacterial community analysis, instead of the current practice at -80 degrees C.
Mølbak
Lars
L
Danish Institute for Food and Veterinary Research, Copenhagen. lam@dfvf.dk
Sommer
Helle M
HM
Johnsen
Kaare
K
Boye
Mette
M
Johansen
Markku
M
Møller
Kristian
K
Leser
Thomas D
TD
D000818:Animals; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000032:analysis* / Q000235:genetics*; D005243:Feces / Q000737:chemistry / Q000382:microbiology*; D005615:Freezing; D012150:Polymorphism, Restriction Fragment Length; D013048:Specimen Handling; D013552:Swine
D004269:DNA, Bacterial