Microbial Communities Structure And In The Northern Slope Of South China Sea & Prilimilary Functional Studies Of Kangiella Strains

The thesis made research on microbial structure about microbial community structure in the northern slope of South China Sea and prilimilary functional studies of kangiella strainsFor doing survey on microbial structure of the Northern South China Sea,PCR in 16S r RNA V4 was used with different primers.The results show that bacteria was consist of 13 phylum level,Proteobacteria and Actinobacteria are the mainly species in seawater,archaea were consisted of5 phylum level,Euryarchaeota and Crenarchaeota are the mainly species in seawater.We also did some research on Kangilla strains which was explosive in2014 autumn cruise at TS07-450 m(3:34),including Kangiella profundi FT102,K.aquimarina DSM 16071,K.geojedonensis YCS-5 and K.koreensis DSM 16069.Analyzed the alkaline serine protease genes expression and physiological characteristics of four Kangiella strains with different metal ions Na⁺,Mg²⁺,Ca²⁺and K⁺.Firstly,the growth of four Kangiella strains in different culture were observed.Then,using Folin method to test the extracellular protease activities of different cultures with2%casein as substrate.According to conserved alkaline serine protease coding sequences(asp1,asp2 and asp3)and pho P/pho Q in 3 Kangiella strains(K.aquimarina DSM 16071,K.geojedonensis YCS-5 and K.koreensis DSM 16069)designed degenerate primers,amplified the aimed genes from K.profundi FT102.Lastly,the Real-time PCR method was used to detect the expression of three conserved alkaline serine protease genes in these four strains.The results showed to us that Na⁺is necessary for the growth of Kangiella strains,Mg²⁺and Ca²⁺have different effects on the transcription of 3 serine protease coding genes asp1,asp2,asp3.The biomass,extracellular protease activity and the transcription level of 3conserved serine protease genes and pho P,pho Q were significantly elevated in K.koreensis DSM 16069 when Mg²⁺was not supplemented in the marine broth 2216E.