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Abstract Recent research has underscored the immense diversity and key biogeochemical roles of large DNA viruses in the ocean. Although they are important constituents of marine ecosystems, it is sometimes difficult to detect these viruses due to their large size and complex genomes. This is true for “jumbo” bacteriophages, which have genome sizes >200 kbp and large capsids reaching up to 0.45 µm in diameter. In this study, we sought to assess the genomic diversity and distribution of these bacteriophages in the ocean by generating and analyzing jumbo phage genomes from metagenomes. We recover 85 marine jumbo phages that ranged in size from 201 to 498 kilobases, and we examine their genetic similarities and biogeography together with a reference database of marine jumbo phage genomes. By analyzing Tara Oceans metagenomic data, we show that although most jumbo phages can be detected in a range of different size fractions, 17 of our bins tend to be found in those greater than 0.22 µm, potentially due to their large size. Our network-based analysis of gene-sharing patterns reveals that jumbo bacteriophages belong to five genome clusters that are typified by diverse replication strategies, genomic repertoires, and potential host ranges. Our analysis of jumbo phage distributions in the ocean reveals that depth is a major factor shaping their biogeography, with some phage genome clusters occurring preferentially in either surface or mesopelagic waters, respectively. Taken together, our findings indicate that jumbo phages are widespread community members in the ocean with complex genomic repertoires and ecological impacts that warrant further targeted investigation.
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This content will become publicly available on December 29, 2026
Isolation and characterization of four novel Vibrio parahaemolyticus bacteriophages from oysters
Vibrio parahaemolyticus(VP) is a bacterial pathogen found in brackish and marine water that infects many marine organisms, such as oysters and shrimp. Consumption of raw or undercooked seafood contaminated withV. parahaemolyticusis a primary cause of seafood-borne gastroenteritis in humans. Due to increasing ocean temperatures,V. parahaemolyticuscontamination of oyster beds in the United States has spread up the east and west coasts to the northern-most states. Promising new research is exploring the isolation of bacteriophages againstV. parahaemolyticuswith a long-term goal to possibly decontaminate oyster beds, thereby expanding the harvest season and allowing for safer consumption of seafood. In this study, store-bought oysters harvested from the Chesapeake Bay in Virginia were used to isolate four bacteriophages with activity against a specificV. parahaemolyticusstrain. A standard double agar overlay plaque assay was used to identify phage activity. After phage isolation, the genomes were sequenced, and transmission electron microscopy (TEM) was performed to visualize the virions. The genomes and TEM images revealed four distinct phages. Three of the phages are distinct isolates that exhibit podovirus-like morphology with short tails and genome sizes of approximately 43 kbp. One phage has siphovirus-like morphology and is a mid-sized tailed phage with a genome size of 80 kbp. Although spot tests performed with the oyster homogenates on up to 10 differentV. parahaemolyticusstrains recovered activity across a wide range of hosts, plaque assays with the isolated phages showed limited host range. Future work will be necessary to determine the viability of using the bacteriophages for elimination ofV. parahaemolyticusin harvested oysters, treatment of aquaculture seed and spat, and/or the environment.
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- Award ID(s):
- 2141862
- PAR ID:
- 10659344
- Editor(s):
- Fernández_Robledo, José A
- Publisher / Repository:
- Public Library of Science
- Date Published:
- Journal Name:
- PLOS One
- Volume:
- 20
- Issue:
- 12
- ISSN:
- 1932-6203
- Page Range / eLocation ID:
- e0339894
- Subject(s) / Keyword(s):
- Bacteriophages, viral diversity, vibrio, pathogens
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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