Molecular and physiological response of foodborne pathogens to selected natural bioactive compounds and development of novel biodegradable polymers with antibacterial activity

Project partner: Dorota Korsak (Principal Investigator: Dusan Misic)

Natural bioactive compounds found in plant have played a crucial role in the domain of discovery and development of new drugs including antimicrobial drugs. 

In our research we want to reveal the molecular and physiological mechanisms of reactions of foodborne pathogenic bacteria exposed to selected natural bioactive molecules (NBMs) that can be used for food preservation in the future.

We are planning to (i) analyze the molecular and physiological mechanisms of actions of selected NBMs on foodborne pathogens, using combined microbiological and „omics“ approaches, (ii) identify and analyze the molecular and physiological basis of the influence of NBMs on biofilm formation and disruption, (iii) analyze the influence of NBMs on bacterial spores development and germination, (iv) identify the potential synergism of NBMs and their stability (activity) under altered physico-chemical conditions. Finally, we want to  develop novel biodegradable polymeric materials with antibacterial properties based on pure active NBMs and their combinations.

FUNDING SOURCES: Opus 18 grant, National Science Centre, Poland

FUNDING AMOUNT: PLN 2 628 600

Mechanisms controlling gene expression in Yersinia enterocolitica at the post-transcriptional level – role of small regulatory RNAs (OmrA, RyhB-1/RyhB-2)

Principal Investigator: Karolina Jaworska (Supervisor Adrianna Raczkowska)

In our research we will determine the participation of the sRNA OmrA, RyhB-1 and RyhB-2 in the post-transcriptional regulation of genes involved in the pathogenicity and adaptation to different environmental niches of enteropathogenic Y. enterocolitica. We will establish whether these sRNAs participate in post-transcriptional control of regulatory and structural genes involved in the virulence and adaptive abilities of Y. enterocolitica and whether OmrA, RyhB-1 and RyhB-2 modulates physiological processes, i.e. motility, microcolony and biofilm formation, adhesion/invasion and colonization, and adaptation to stress conditions. Because of the multiphasic life cycle of Y. enterocolitica, which includes periods of residence in the external environment and the host, we expect that these sRNAs regulate cellular processes that permit colonization of these different habitats. We hope to provide new insights into the role of OmrA, RyhB-1 and RyhB-2 in the pathophysiology of Y. enterocolitica, as well as other virulent species  of genus Yersinia, namely Y. pestis and Y. pseudotuberculosis.

FUNDING SOURCES: Preludium 17 grant, National Science Centre, Poland

FUNDING AMOUNT: PLN 206 440

Functional analysis of ferritin operon genes encoding unknown factors involved in virulence, antibiotic resistance and stress adaptation of Listeria monocytogenes 

Principal Investigator: Agata Krawczyk-Balska (Project partner: Birgitte Kallipolitis and Maria Górna)

Listeria monocytogenes is an opportunistic humans and animals pathogen that can adapt to survival in a wide range of environmental conditions. Cases of listeriosis, an infection with a mortality rate up to 30 % despite undertaken antibiotic therapy, are associated with the consumption of food contaminated with this microorganism.

Ferritin is a protein which plays an important role in the virulence, resistance to β-lactams antibiotics and adaptation to various stress conditions of L. monocytogenes. This protein is encoded by the first gene of the operon in which four other genes are located.  The physiological function and role in stress adaptation of the ferritin operon genes is unknown. In the project, we intend to investigate the role and mechanism of action of these genes through the use of bacterial genetics, microbiology and high-throughput methods as well as studies on the tissue cultures and animal model.

In an effort to decrease the significant human and economic costs associated with listeriosis, it is crucial to develop of methodologies to prevent the survival of L. monocytogenes in the clinical and non-clinical settings. In the respect, the identification and characterization of so far unknown factors which contribute to virulence and stress adaptation of L. monocytogenes could pave the way to develop new treatment strategies for this important pathogen. 

FUNDING SOURCES: Opus 11 grant, National Science Centre, Poland

FUNDING AMOUNT: PLN 772 600

Mechanisms controlling gene expression in Yersinia enterocolitica at the transcriptional level – role of EnvZ/OmpR, two-component signal transduction system

Principal Investigators: Katarzyna Brzostek

Our previous studies have demonstrated, that OmpR, the response regulator of two component transduction system EnvZ/OmpR, participates in the pathophysiology of Yersinia enterocolitica. By acting as a global regulator of gene expression, including virulence genes, OmpR produces pleiotropic effects in this enteropathogen. OmpR is involved in the adaptation of this pathogen to multiple environmental stresses by controlling of various cellular processes and functions, including adhesion, invasion, motility, Yop production, biofilm formation, and multidrug and serum resistance. 

Our current research focuses on the contribution of OmpR to iron homeostasis in Y. enterocolitica. We will establish whether there exists direct OmpR-dependent regulation of fur transcription and consequently whether or not OmpR controls expression of selected Fur regulon members.

Besides expanding the knowledge base concerning OmpR, our research highlight TCSs as potential targets for inhibitors that might be used therapeutically to fight bacterial infections in this era of widespread antibiotic resistance.

FUNDING SOURCES: Opus 11 grant, National Science Centre, Poland

FUNDING AMOUNT: PLN 903 700

Elucidation of the mechanism of regulation of expression of ferritin operon genes by the chaperone RNA - Hfq protein of Listeria monocytogenes and its role in the metabolism of heme iron and adaptation to various stresses

Principal Investigator: Agata Krawczyk-Balska (Project partner: Birgitte Kallipolitis)

Hfq is RNA-binding protein highly conserved in prokaryotes. It is best known as a RNA chaperone involved in post-transcriptional regulation of gene expression by promoting interaction between sRNA and mRNA. Hfq function as sRNA-mRNA matchmaker is well established in Gram-negative species, in Gram-positive ones is still inconclusive. While, the ability of Hfq from different Gram-positive species to bind sRNA is well documented, so far only a single sRNA from Gram-positive species is known to rely on Hfq for stability and base pairing to target mRNAs, namely Listeria monocytogenes LhrA. Besides of LhrA, sRNAs from LhrC family are known to interact with the chaperone Hfq of L. monocytogenes. However, so far the interactions between LhrCs and mRNAs targets have been shown to be Hfq-independent.

Our preliminary studies revealed that LhrC5 belongs to the ferritin operon of L. monocytogenes, and what's more, Hfq interacts in vivo with mRNAs of genes from the operon. In the project, we will establish whether Hfq and LhrC5 of L. monocytogenes are involved in regulation of expression of the ferritin operon genes in various stress conditions and subsequently elucidate the molecular mechanism of the regulation. 

The results of the project will provide a new data concerning the regulatory mechanisms of Hfq in Gram-positive bacteria and a more comprehensive view of the post-transcriptional regulation of stress response in L. monocytogenes. 

FUNDING SOURCES: Sonata Bis 5 grant, National Science Centre, Poland

FUNDING AMOUNT: PLN 1 590 720

The role of Listeria monocytogenes efflux pumps in determining resistance, biofilm formation and maintaining cell homeostasis

Principal Investigator: Dorota Korsak

The widespread and inappropriate use of antimicrobials, such as antibiotics and chemotherapeutics,  disinfectants or antiseptics  in medicine, veterinary, agriculture or industry has led to selection and spread of resistant strains of bacteria for the last few decades. Microorganisms developed various mechanisms of resistance in response to the presence of antibacterial compounds in the environment. One of the strategies frequently used by bacteria is active efflux responsible for moving such compounds out of the cell into the external environment. Transport of the substances is possible due to specific transport proteins present in the cell membrane. 

In our research we determine the role of genes which potentially encode the transport proteins (efflux proteins) of the pathogen bacterium Listeria monocytogenes in development of tolerance or resistance of that bacterium to various antibacterial compounds, as well as to define their functions in the process of formation of biofilms and maintenance of the cellular homeostasis.

Resistance of Listeria spp. to different toxic compounds

Principal Investigator: Dorota Korsak

In our research we determine the susceptibility of nonpathoegenic and pathogenic Listeria strains to different antimicrobials, disinfectans and heavy metals. We identify the genetic basis of the resistance, genomic localization of the resistance genes and possibility of their transfer between different Listeria species.