Abstract: The total microbial DNA of mice feces was extracted by GITC (guandine thiocyanate) method, CTAB (hexadecyl trimethyl ammonium bromide) method, Tiangen and Omega fecal DNA extraction kits. The yield and purity of the extracted DNA were determined by spectrophotometer of NanoDrop 2000. The results showed that the DNA extracted by the commercial DNA extraction kits was of the highest purity but of lowest yield, while the DNA with highest yield and lowest purity was obtained by CTAB method. The DNA extracted from mice feces by using GITC method showed higher purity than that retrieved from CTAB method, and higher yield than that extracted by commercial DNA extraction kits. The bacterial richness and diversity were further compared among the four methods by using 16S rDNA-PCR-DGGE fingerprinting method. Results revealed that significantly higher bacterial richness and diversity were observed in the community extracted from GITC method than that from the other three methods. In conclusion, the GITC method developed in our lab had some advantages as a fecal DNA extraction protocol, with higher DNA quality and quantity, specifically, higher richness and diversity of intestinal microbiota, compared with CTAB method, Tiangen and Omega fecal DNA extraction kits.

Key words: community production, saturation threshold, climate warming, biomass allocation, alpine meadow, nitrogen addition