Adaptive lifestyle of bacteria determines phage-bacteria interaction

Abstract

Bacteriophages and their interactions with microbes are not well understood. As a first step toward achieving a better understanding, we isolated and sequenced the Curvibacter phage PCA1 for the purpose of eliminating Curvibacter sp. AEP1.3, the main colonizer of Hydra vulgaris AEP. Our experiments showed that PCA1 phage caused a strong, virulent infection only in sessile Curvibacter sp. AEP1.3 but was unable to infect planktonic and host-associated bacterial cells of the same strain. In an effort to investigate this phenomenon, we compared sessile, planktonic, and host-associated bacteria via RNA sequencing and found that all three states differed significantly in their expression patterns. This finding led us to propose that the adaptive lifestyle of Curvibacter sp. AEP1.3 results in varying degrees of susceptibility to bacteriophage infection. This concept could be relevant for phage research and phage therapy in particular. Finally, we were able to induce phage infection in planktonic cells and pinpoint the infection process to a membrane protein. We further identified potential phage-binding protein candidates based on expression pattern analysis.

Determinants in the phage life cycle: The dynamic nature of ssDNA phage FLiP and host interactions under varying environmental conditions and growth phases

“…Most often, FLiP replication is weak in traditional liquid cultures and the OD of the liquid cultures do not drop during FLiP infection (Figures S3 and S4), meaning that only a few cells are lysed, which was also indicated by the EM images (Figure 4). The efficient FLiP infection seems to require the surface attachment of the host, as has been observed also with some other Flavobacterium-infecting phages (Almeida et al, 2019;Laanto et al, 2015) as well as in some other phagehost systems (Ulrich et al, 2022). So far described Flavobacterium infecting phages appear to be associated with Type 9 Secretion System (T9SS) (Castillo et al, 2021;Kunttu et al, 2021;Shrivastava et al, 2013).…”

Optimizing bacteriophage treatment of resistant Pseudomonas

“…As we have learned previously, the ability of phages to infect a bacterium on solid medium does not guarantee success when infecting its bacterial host in liquid culture ( 34 ). Since our goal was to prepare a therapeutic intervention regimen using bacteriophages effective against bacteria in liquid culture and on solid surfaces, we tested infectivity of all our phages in P. alcaligenes liquid culture.…”

“…DNA of Psari100M and CL phage was extracted using CTAB extraction buffer (100 mM Tris at a pH of 8, 3 M NaCl, 20 mM EDTA, and 3% cetyltrimethylammonium bromide), as described in our previous report ( 34 ). DNA was re-suspended in 40 µL DNase-free water and stored at −80°C before sequencing.…”