Preliminary Investigation Of Microbial Community Dynamics Of The Early-stage Biofouling

Oceanic biofouling brings huge economic losses each year all around the world. Itis in an urgent need to develop efficient and environmentally safe antifouling reagents.Our lab is doing best to combine present antifouling paints with some components thatcan prevent growth of microbes in the early stage of biofouling. In order to achievethis goal, it is essential to investigate dynamic changes of microbial community.This study includes the following parts:(1) Fliping chart experiments for one year.Based on the results, eight groups of steel plates have designed and suspended in themarine water at Little island (Weihai). Microbial samples are collected every other day.The purpose is to know microbial community dynamics in the early20days.(2)Genome samples are extracted from the steel plate samples and are used as templatefor16s rDNA amplification. The amplified DNA fragments were cloned into E. coliusing TA-cloning. The selected colonies are grown by cell culture for plasmid isolation.Those qualified colonies have been sequenced.(3) Based on the sequencing results,Blast analysis is undertaken to get bacteria information for the basic microbialcommunity composition.(4) Using those bacteria with whole genome sequences,species-specific primers have been designed to develop quantitative PCR (qPCR)protocol to acquire bacterial type and amount information. Thus, the preliminarydynamic process of some early-stage bacteria is able to be described.The conclusions:(1) After a one-year observation, it has been decided that the first20days couldbe treated as the early stage of biofouling. Steel plates have been set up at water depthsof1.3m,1.6m and1.9m at the three locations: Little Island, Weihai Port and Shandafarm. Biofouling processes in the three locations are compared and Little Island isfinally chosen to collect microbe samples attached to the steel plates in the early15days.(2) Through the16s rDNA sequence analysis, we preliminarily obtain24types ofearly fouling microorganisms in Little Island. Eight types of microbes are detected on1-day plates, while fifteen types of microbes are detected on15-day plates. As timeincreases within the experimental period, the types of microorganisms attached to steelplates showed a rising trend.(3) By bioinformatics and computaional tools, six pairs of species-specificprimers are determined for Pseudoalteromonas tetraodonis, Pseudoalteromonasatlantica, Pseudoalteromonas marina, Pseudoalteromonas issachenkonii,Marinomonas pontica and Psychrobacter marincola. With the analysis of the Ct values of qPCR, we find the quantitative changes of each type of bacterium attached to thesteel plates between day-1to day-15. These data provides a good start to studydynamics of microbial community of early-stage biofouling.