| Marine micro-organisms are the smallest and largest populations of life on the planet.Marine micro-organisms have existed on Earth for billions of years.During the long period of time,marine micro-biological systems have contributed enormous biomass and productivity.The key factors in the cycle of production factors are linked to life and non-living systems.Marine planktonic viruses together with phytoplankton,zooplankton and planktonic bacteria constitute a complete plankton community.With the development of microscopy technology,people have recognized the existence of micro-organisms,while marine viruses are the most numerous particles in life,and biomass is second only to prokaryotes.The study of marine viruses began in the 1960s.In the 1990s,its enormous quantity,important ecological functions and status were recognized by people and became one of the hottest research topics in marine ecology.The diversity and huge number of species of bacteriophages in the ocean far exceeds our previous understanding.Our exploration of marine bacteriophages has only just begun.In this dissertation,the representative strains of Alteromonas,Roseobacter,and Eythrobacter,which are widely distributed and have strong environmental adaptability,were selected as hosts for phage isolation,purification and physiological and biochemical properties analysis.The main results are as follows:We used two representative strains of Alteromonas of different ecological bacteria as the host,of which Alteromonas ATCC 27126 is a representative "surface ecotype" strain in the global surface sea area.The "deep-sea ecotype" strain AltDE isolated from the deep water layer from the South Adriatic Sea.A new siphovirus phage bacteriophage RAV6062 with Alteromonas ATCC 27126 as host was obtained.Two strains were no-tailed phage obtained by Alteromonas AltDE as the host,and the whole genome analysis of physiological parameters was described on RAV6062.Studies have shown that RAV6062 has a icosahedral head and a long non-telescopic tail.It is insensitive to chloroform and can infect other strains that are similar to the host in evolutionary relationship.Genome sequencing showed that RAV6062 had a total genome length of 42722bp and a GC content of 54.72%.The whole genome alignment showed that RAV6062 is a relatively new type of phage.Among the 73 encoded proteins,28 functional genes were annotated.In addition to the tail and head structural proteins,there are also related coding genes for phage replication.ORF4,ORF5,and ORF6 are three DNA polymerase encoding genes similar to Vibriophage.Highly homologous DNA polymerase-encoding genes were also found in the genome of phage vB_AspP-H4/4.Based on the diversity of phage morphology,we selected 8 strains of bacteriophage which were hosted by 3 strains of Dinoroseobacter shibae DFL12T and Erythrobacter litlitalis DSM 8509 and Erythrobacter sp.JL475 for whole proteomics research.The proteome results showed that the phage are mainly assembled by phage tail protein,tail tube protein,tail fibrin,head and tail connexin,major capsid protein,minor capsid protein,head morphogenetic protein,head decoration protein and others Structural proteins.The enzymes involved in phage replication and metabolism include single-stranded DNA-binding enzymes,DNA polymerases,D-alanyl-D-alanine carboxylase,RNA polymerase,ribonuclease,and terminating enzymes.By comparison of relative abundances,the relative abundances of proteins of different phage were consistent.The relative abundance of structural proteins was above 60%,of which the main coat protein content was the highest,accounting for about 30%to 70%,followed by channel proteins and tail proteins,accounting for 2%to 10%,DNA replication And the proportion of enzymes that regulate life activities is very small,with the vast majority less than 1%. |
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