Role of DNA in bacterial aggregation.
The role of DNA in bacterial aggregation was determined using various types of DNA and Escherichia coli, a good model for investigating the correlation between added polymer and bacterial aggregation and adsorption of polymer to bacterial surfaces. The results of the aggregation assay suggest that extracellular DNA indeed increased the aggregation percentage of E. coli, but this effect was dependent on DNA concentration and length. Moreover, DNA promoted bacterial aggregation in a type-nonspecific way. The combined results of the aggregation assay and the adsorption assay show further that the promotion of E. coli aggregation by DNA occurred along with adsorption of DNA to E. coli. Consequently, the possible mechanisms for DNA-promoted bacterial aggregation are discussed. Using fluorescent-labeled DNA, we mapped DNA within the E. coli aggregates. Subsequently, introduction of DNase I broke up the DNA-involved E. coli aggregates. These results suggest that DNA functions as a molecular bridge to promote E. coli aggregation.
Liu
Hui-Hui
HH
Laboratory of Microbial Genetics, College of Life Sciences, Wuhan University, Wuhan 430072, PR China.
Yang
Yi-Ran
YR
Shen
Xin-Cheng
XC
Zhang
Zhi-Ling
ZL
Shen
Ping
P
Xie
Zhi-Xiong
ZX
D001422:Bacterial Adhesion; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism*; D004279:DNA, Viral / Q000737:chemistry / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D004926:Escherichia coli / Q000502:physiology*; D008970:Molecular Weight
D004269:DNA, Bacterial; D004279:DNA, Viral; D003850:Deoxyribonuclease I