A novel vibriophage exhibits inhibitory activity against host protein synthesis machinery

Abstract

Since the emergence of deadly pathogens and multidrug-resistant bacteria at an alarmingly increased rate, bacteriophages have been developed as a controlling bioagent to prevent the spread of pathogenic bacteria. One of these pathogens, disease-causing Vibrio parahaemolyticus (Vp AHPND ) which induces acute hepatopancreatic necrosis, is considered one of the deadliest shrimp pathogens, and has recently become resistant to various classes of antibiotics. Here, we discovered a novel vibriophage that specifically targets the vibrio host, VP AHPND . The vibriophage, designated Seahorse, was classified in the family Siphoviridae because of its icosahedral capsid surrounded by head fibers and a non-contractile long tail. Phage Seahorse was able to infect the host in a broad range of pH and temperatures, and it had a relatively short latent period (nearly 30 minutes) in which it produced progeny at 72 particles per cell at the end of its lytic cycle. Upon phage infection, the host nucleoid condensed and became toroidal, similar to the bacterial DNA morphology seen during tetracycline treatment, suggesting that phage Seahorse hijacked host biosynthesis pathways through protein translation. As phage Seahorse genome encodes 48 open reading frames with many hypothetical proteins, this genome could be a potential untapped resource for the discovery of phage-derived therapeutic proteins.Vibrio is a genus of motile Gram-negative bacteria that possesses a curved-rod cell shape with a single flagellum. Vibrios are abundant and diverse bacteria that are typically found in marine habitats. The genus Vibrio consists of 14 recognized clades and at least 86 different species 1 . While some of them are not pathogenic, many can cause serious health effects in both human and aquatic life. Due to the continuously rising ocean temperature, the composition of vibrio in the ocean microbiome has been reported to be higher than usual 2-4 . This vibrio-rich environment might increase the incident of a vibrio outbreak in the near future posing risks to global health 2 .Vibrio parahaemolyticus, which is one of the disease-causing Vibrio species, is pathogenic to both humans and marine animals 5 . Consumption of raw seafoods contaminated with the bacteria can cause acute gastroenteritis 5,6 . This opportunistic bacterium is also able to infect through an open wound which can lead to sepsis and, in rare cases, subsequent death in immunocompromised patients 7,8 . Moreover, V. parahaemolyticus that has acquired a plasmid encoding the deadly binary toxins PirA vp /PirB vp is even more virulent 9 . The V. parahaemolyticus strain harboring the plasmid has been found to cause a newly emerging disease in shrimp, known as acute hepatopancreatic necrosis disease (AHPND) 9 . Moreover, the AHPND-causing plasmid is also found to be transferable among other vibrios, increasing the chance of the disease spreading regionally and globally 10 . Unsurprisingly, the spread of AHPND has been reported in many countries, including China, Vietnam, Malaysia, Thailand, Me...

Phage-resistant Pseudomonas aeruginosa against a novel lytic phage JJ01 exhibits hypersensitivity to colistin and reduces biofilm production

“…The supernatant was serially diluted in SM buffer, and a spot titer test was performed to determine the number of free phage particles in the supernatant. The experiment was performed in triplicates ( Thammatinna et al, 2020 ).…”

Nucleus-forming jumbophage PhiKZ therapeutically outcompetes non-nucleus-forming jumbophage Callisto

“…To observe the progress of the replication cycle of the phage Callisto in comparison to the well-studied chimalliviruses PhiKZ, we performed a single-cell infection assay and observed DAPI-staining DNA to follow the phage reproduction process in the host cells. 41 , 52 The results showed that, during the phage infections, the infected Pseudomonas cells had their morphology altered throughout the time, which might be a result of the phage infections compared to the uninfected cell control ( Figures 3 A, 3C, and 3D). During infection with phage PhiKZ ( Figure 3 A; PhiKZ), the phage assembled the phage nucleus localized close to the midcell of the host ( Figure 3 A; PhiKZ, green arrows).…”

The First Cbk-Like Phage Infecting Erythrobacter, Representing a Novel Siphoviral Genus

“…Two genes (ORFs 8 and 13) were predicted to encode virions and phage structure proteins. Major capsid protein (ORF 9) and minor capsid protein (ORF 11) were identified in the genome; the former is the major structural component of icosahedral virus particles, and the latter is believed to enhance the stability of capsid structure by forming protein–protein interactions (Thammatinna et al, 2020 ). Four ORFs were related to tube structure, including major tail tube protein (ORF 17), which is used for viral genome delivery to the host cells (Davidson et al, 2012 ); tail fiber protein (ORF 25), which is responsible for host-range determination (Garcia-Doval and van Raaij, 2012 ); and two tail proteins (ORFs 24 and 26).…”