So far, we have made significant progress towards achieving our aims according to our original plan. Our major results and progress are:
1) We revealed that the CORE provides the basis for a nanotube-organelle that connects pathogenic E. coli (EPEC) to its host, enabling host nutrient extraction (Pal et al., 2019 Cell, Cell cover, Cell featured article, Nature Highlights) (see Figure "Cell cover").
2) We discovered that the conserved CORE components serve dually for flagellar and nanotube assembly in diverse species belonging to different phyla (Bhattacharya et al., 2019 Cell Reports) (see Figure "Bs nanotubes").
3) We found that bacterial intercellular nanotube connection is enabled by the delivery of lytic enzymes over nanotubes from a donor bacterium to rapture the recipient bacterium cell wall (Baidya et al., 2020 Nature Communications) (see Figure "Bs Sa nanotube").
4) Using an array of biochemical and genetic screens, we identified new CORE-nanotube components in the model organisms EPEC and B. subtilis.
5) By exploring nanotube formation of natural B. subtilis isolates, we revealed the existence of a protein that interacts with the CORE to block cargo delivery.
6) With the Team Member Prof. Waksman (Birkbeck, UK), we solved the structure of the CORE complex of EPEC, and identified mutations that specifically affect CORE-nanotube formation.
7) By visualizing CORE-apparatuses by cryo-ET, in collaboration with Prof. Jensen (Caltech, USA), we identified a new CORE-dependent organelle (Kaplan et al., J. Bact 2022), that we are now investigating in depth.
8) We defined the global protein delivery from B. subtilis to EPEC, revealing that B. subtilis sends an array of enzymes to degrade proteins of EPEC, as a mode to acquire nutrients.
9) We identified OmpA, a porin, and LpxR, a lipid A-deacylase, as proteins deposited on the host surface during infection.
10) We formulated a selective labeling approach of newly synthesized RNA in vivo without any need for genetic manipulation.
11) We determined the EPEC RNA interactome during infection and its impact on CORE (Pearl Mizrahi et al. Sci Adv, 2021).
12) By investigating the impact of CORE on the expansion of plaques, caused by bacteriophage infection, we discovered a phage tolerance response that is elicited by the non-infected bacteria, in response to infection of their neighbors (Tzipilevich et al, EMBO J 2022).
13) We devised a new approach to record bacteria spatial interactions in natural communities.
14) We developed a novel way to observe and record nanotube formation and dynamics by real-time microscopy. For the first time, we could image events of nanotube protrusions from the CORE, and the establishment of nanotube connections between neighboring bacteria.
