Pseudomonas aeruginosa is able to colonize various habitats and utilize a broad range of nutrients. To
establish an acute infection, P. aeruginosa employs an extensive arsenal of virulence determinants,
including the type III secretion system (T3SS). T3SS is a multi-protein complex with a needle-like structure,
delivering effector proteins from the bacteria’s cytosol directly into the host’s cytosol. Despite the versatility
of hosts, environments and large genome, only six known effectors were identified in this pathogen thus far.
This sets up the basis for our hypothesis that more undiscovered T3SS effectors are encoded in the P.
aeruginosa genome. A machine-learning algorithm constructed a top-ranked putative effectors list, using
several genomes of P. aeruginosa strains representing both clinical isolates and laboratory strains. We
identified six novel effectors, PemA-F, and assessed their effect on the multicellular organism model
—Caenorhabditis elegans. Using a lifespan assay, we established that T3SS plays an important role in P.
aeruginosa infection of C. elegans. We found that PemB showed a toxic effect on C. elegans, via the
Programmed Cell Death pathway. Using a microfluidic device, we revealed that PemB is localized in the C.
elegans intestine. Hence, we examined whether P. aeruginosa has a physiological effect on C. elegans
intestine using the intestine staining approach. We found that PemB causes leakage in C. elegans
intestine, impairing its integrity. Our next goal is to unravel the molecular pathway and protein interactions
of PemB in the nematode. The findings of this research constitute an important step towards a better
understanding of virulence and host evasion mechanisms adopted by P. aeruginosa.

_Pseudomonas aeruginosa_ is able to colonize various habitats and utilize a broad range of nutrients. To
establish an acute infection, _P. aeruginosa_ employs an extensive arsenal of virulence determinants,
including the type III secretion system (T3SS). T3SS is a multi-protein complex with a needle-like structure,
delivering effector proteins from the bacteria’s cytosol directly into the host’s cytosol. Despite the versatility
of hosts, environments and large genome, only six known effectors were identified in this pathogen thus far.
This sets up the basis for our hypothesis that more undiscovered T3SS effectors are encoded in the _P._
_aeruginosa_ genome. A machine-learning algorithm constructed a top-ranked putative effectors list, using
several genomes of _P. aeruginosa_ strains representing both clinical isolates and laboratory strains. We
identified six novel effectors, PemA-F, and assessed their effect on the multicellular organism model
—_Caenorhabditis elegans_. Using a lifespan assay, we established that T3SS plays an important role in _P._
_aeruginosa_ infection of _C. elegans_. We found that PemB showed a toxic effect on _C. elegans_, via the
Programmed Cell Death pathway. Using a microfluidic device, we revealed that PemB is localized in the _C._
_elegans_ intestine. Hence, we examined whether P. aeruginosa has a physiological effect on C. elegans
intestine using the intestine staining approach. We found that PemB causes leakage in _C. elegans_
intestine, impairing its integrity. Our next goal is to unravel the molecular pathway and protein interactions
of PemB in the nematode. The findings of this research constitute an important step towards a better
understanding of virulence and host evasion mechanisms adopted by _P. aeruginosa_.

Characterization of PemB, a novel effector of Pseudomonas aeruginosa type III secretion system

Exploring the intricacies of host-pathogen communication is vital in order to understand why
some microbes persist within a host, while others are effectively cleared. As such,
host-pathogen communication is an urgent area of research underpinning human health
and disease, especially given the emerging concerns of antibiotic resistance.
Understanding host-pathogen pathways requires intricate knowledge in the fields of both
microbiology and immunology.

Living in a world of specialists, where scientists sometimes invest their whole career
studying one organism, a specific pathway or a protein, multidisciplinary discussions of
host-pathogen interactions are highly needed. This international conference will provide
such a forum for scientific exchange at the highest level, between scientists from different
research areas related to host-pathogen interactions, with the aim to trigger fruitful
collaborations addressing the urgent questions in the field.

This meeting has an additional special focus of bringing researchers from Ireland, Denmark
and Israel together to learn about cutting edge biology and form new collaborations.
Thus, the conference will be a showcase for the exciting and original research emanating
from these three small but innovative countries.