Comparative analysis of the intestinal microbial flora diversity of adult and young African lions / 中国兽医学报

In this study,the intestinal microbial flora diversity of adult and young African lions in the same breeding environment was detected by PCR-DGGE technique.Total bacterial DNA was extracted and 16S rDNA V3 region was amplified,then conducting PCR-DGGE.Subsequently,the specific bands of DGGE were cloned and sequenced.The bacterial species were identified by comparing the sequence through BLAST.The results indicated that the intestinal microbial flora of adult African lions includes Clostridium,Lachnospiraceae bacterium,Anaerovorax,Lactococcus,Peptostreptococcus and Blautia.While the intestinal microbial flora of young African lions is lesser,most bacteria are common to adult and young lions,such as Bacteroidetes bacterium and rumen bacterium.The UPGMA clustering analysis of the DGGE fingerprint showed the similarities of the bacteria structures between adult and young African lions were only 34％.These results revealed that the intestinal microbial flora has significant difference in different stages of African lions.This study lays a foundation for the development of microecological agents in different growth stages of wild animals.

Zinc-finger recombinase activities in vitro.

Zinc-finger recombinases (ZFRs) are chimaeric proteins comprising a serine recombinase catalytic domain linked to a zinc-finger DNA binding domain. ZFRs can be tailored to promote site-specific recombination at diverse 'Z-sites', which each comprise a central core sequence flanked by zinc-finger domain-binding motifs. Here, we show that purified ZFRs catalyse efficient high-specificity reciprocal recombination between pairs of Z-sites in vitro. No off-site activity was detected. Under different reaction conditions, ZFRs can catalyse Z-site-specific double-strand DNA cleavage. ZFR recombination activity in Escherichia coli and in vitro is highly dependent on the length of the Z-site core sequence. We show that this length effect is manifested at reaction steps prior to formation of recombinants (binding, synapsis and DNA cleavage). The design of the ZFR protein itself is also a crucial variable affecting activity. A ZFR with a very short (2 amino acids) peptide linkage between the catalytic and zinc-finger domains has high activity in vitro, whereas a ZFR with a very long linker was less recombination-proficient and less sensitive to variations in Z-site length. We discuss the causes of these phenomena, and their implications for practical applications of ZFRs.