Isolation, Characterization Of Thermus Phage TTP23from Tengchong Hot Spring, And Research On Interaction Relationship Of TSP4and Its Host Cell

Thermus is an ancient group of thermophilus eubacteria and is regarded as a model organism of thermophiles. Reccently, Thermus phages have obtained more attention for their unique biological and evolutional characteristics. Total of4families of Thermus phages:Myoviridae, Siphoviridae, Tectiviridae and Inoviridae were reported. In addition, more researches have focused on the interaction relationship between phages and its host. And the related research included the interaction between Thermus thermophilus HB27and Thermus thermophilus HB8with bacteriophage P23-45andΦYS40in molecular level, respectively.Thermus phage TTP23(Thermus Tectiviridae phage23) was isolated from high temperature alkaline hot springs in Tengchong, Yunnan. TTP23had double-strand DNA and had coat proteins and membranes as the cover layer(5nm in thickness) The diameter of TTP23was60nm, and its optimum growth temperature and pH were65-70℃and pH7-7.5respectively. Infection of TTP23could cause the lysis of host cells, and released a lot of progeny phage particles.In addition, RNA extraction, real-time fluorescent quantitative PCR, bioinformatics and other approaches were used to investigate the interaction relationship between TSP4and its host, Results showed that TSP4functional genes were temporal transcription, and were controlled by early, middle and late promoter,respectively. Early promoter characterized by the5'-TTATTCTTTTa-3" sequence and middle and late promoter shared the5'-TATAnt-3'sequence, respectively. Early promoter controlled by the virus-coded RNAP, but middle and late promoter controlled by host-coded RNAP. After infection its host, TSP4could hijack the host cell transcription, translation and metabolic processes,In addition to TSP4infection, host bacteria could activate the genomic CRISPRs, CRISPR-associated (CAS) gene expression, and cAMP signal function to maintain the host cell defense system (response system) to stop the virus or exogenous replicon from attacking host cells.This article will help us to realize the distribution and characteristic of the thermophilic bacteria phages in Tengchong hot springs, understand the interaction of viruses with its host cells at gene level and the evolution of thermophilic bacteria at high temperature environment.