No abstract

We used the double-agar layer method to isolate a novel Marinobacter marina bacteriophage, B23, from the surface water sample of the Bohai sea of China. There is some work to better understand the phage. The result of transmission electron microscopy revealed that B23 belongs to the family Siphoviridae with a head of 80 nm in diameter and a tail of 230 nm. Microbiological characterization evidenced that phage B23 is stable at the temperatures from - 25 to 60 °C, and showed vigorous vitality at pH between 4.0 and 12.0. One-step growth experiment showed that it had a longer latent period and higher lysis efficiency. Furthermore, the complete genome of B23 was sequenced and analyzed, which consists of a 35132 bp DNA with a G + C content of 59.8% and 50 putative open reading frames. The genome was divided into five parts, consisting of DNA replication and regulation, phage packaging, phage structure, host lysis and hypothetical protein.

Green tides caused by Ulva prolifera occur annually in the Yellow Sea, potentially influencing the marine microorganisms. Here, we focused on the variations in marine bacterial and archaeal communities during an U. prolifera green tide in coastal Qingdao areas with Illumina high-throughput sequencing analysis. Our results revealed that the diversity and structure of bacterial and archaeal communities, as well as the organization and structure of microbial co-occurrence networks, varied during the green tide. The decline phase may be favorable to the bacterial and archaeal diversity and richness. The bacterial community, as well as the archaeal community, showed clear variations between the outbreak and decline phases. A simpler and less connected microbial co-occurrence network was observed during the outbreak phase compared with the decline phase. Flavobacteriales and Rhodobacterales separately dominated the bacterial community during the outbreak and decline phase, and Marine Group II (MGII) dominated the archaeal community during the green tide. Combined with microbial co-occurrence network analysis, Flavobacteriales, Rhodobacterales and MGII may be important organisms during the green tide. Temperature, chlorophyll a content and salinity may have an important impact on the variations in bacterial and archaeal communities during the green tide.