scholarly journals The de novo Purine Biosynthesis Pathway Is the Only Commonly Regulated Cellular Pathway during Biofilm Formation in TSB-Based Medium in Staphylococcus aureus and Enterococcus faecalis

2021 ◽  
Keyword(s):  
Staphylococcus Aureus ◽  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
De Novo ◽  
Purine Biosynthesis ◽  
Biosynthesis Pathway ◽  
Chronic Infections ◽  
De Novo Purine Biosynthesis ◽  
Cellular Pathways ◽  
Different Strains

Bacterial biofilms are involved in chronic infections and confer 10 to 1,000 times more resistance to antibiotics compared with planktonic growth, leading to complications and treatment failure. When transitioning from a planktonic lifestyle to biofilms, some Gram-positive bacteria are likely to modulate several cellular pathways, including central carbon metabolism, biosynthesis pathways, and production of secondary metabolites. These metabolic adaptations might play a crucial role in biofilm formation by Gram-positive pathogens such as Staphylococcus aureus and Enterococcus faecalis. Here, we performed a transcriptomic approach to identify cellular pathways that might be similarly regulated during biofilm formation in these bacteria. Different strains and biofilm-inducing media were used to identify a set of regulated genes that are common and independent of the environment or accessory genomes analyzed. Our approach highlighted that the de novo purine biosynthesis pathway was upregulated in biofilms of both species when using a tryptone soy broth-based medium but not so when a brain heart infusion-based medium was used. We did not identify other pathways commonly regulated between both pathogens. Gene deletions and usage of a drug targeting a key enzyme showed the importance of this pathway in biofilm formation of S. aureus. The importance of the de novo purine biosynthesis pathway might reflect an important need for purine during biofilm establishment, and thus could constitute a promising drug target. IMPORTANCE Biofilms are often involved in nosocomial infections and can cause serious chronic infections if not treated properly. Current anti-biofilm strategies rely on antibiotic usage, but they have a limited impact because of the biofilm intrinsic tolerance to drugs. Metabolism remodeling likely plays a central role during biofilm formation. Using comparative transcriptomics of different strains of Staphylococcus aureus and Enterococcus faecalis, we determined that almost all cellular adaptations are not shared between strains and species. Interestingly, we observed that the de novo purine biosynthesis pathway was upregulated during biofilm formation by both species in a specific medium. The requirement for purine could constitute an interesting new anti-biofilm target with a wide spectrum that could also prevent resistance evolution. These results are also relevant to a better understanding of the physiology of biofilm formation.

scholarly journals Cellular adaptation and the importance of the purine biosynthesis pathway during biofilm formation in Gram-positive pathogens

2020 ◽  
Author(s):  
Martin Gélinas ◽  
Léa Museau ◽  
Arielle Milot ◽  
Pascale B Beauregard
Keyword(s):  
Secondary Metabolites ◽  
Biofilm Formation ◽  
Gene Set Enrichment Analysis ◽  
Purine Biosynthesis ◽  
Biosynthesis Pathway ◽  
Gram Positive ◽  
Cellular Adaptation ◽  
Gram Positive Bacteria ◽  
Cellular Pathways ◽  
Different Strains

Bacterial biofilms are involved in chronic infections and confer 10 to 1000 times more resistance to antibiotics, leading to treatment failure and complications. When transitioning from a planktonic lifestyle to biofilms, certain Gram-positive bacteria are likely to modulate several cellular pathways including central carbon metabolism, primary biosynthesis pathways and production of secondary metabolites. These metabolic adaptations might play a crucial role in biofilm formation by Gram-positive pathogens such as Staphylococcus aureus and Enterococcus faecalis. Here, we performed a transcriptomic approach to identify cellular pathways that might be similarly regulated during biofilm formation in these bacteria. Different strains and biofilm-inducing media were used to identify a set of regulated genes that are common and independent of the environment or accessory genomes analysed. The gene set enrichment analysis of the transcriptome of four different strains of Gram-positive bacteria identified biosynthesis of secondary metabolites, biosynthesis of antibiotics and purine biosynthesis as three commonly upregulated pathways in biofilm. Our approach did not highlight downregulated pathways during biofilm formation that were common to S. aureus and E. faecalis. Of the three upregulated pathways, the de novo IMP biosynthesis pathway constitutes a promising target of cellular adaptation during biofilm formation. Gene deletions in this pathway, particularly purN, purL, purQ, purH and purM significantly impaired biofilm formation of S. aureus.

scholarly journals De Novo Purine Biosynthesis Is Required for Intracellular Growth of Staphylococcus aureus and for the Hypervirulence Phenotype of a purR Mutant

2020 ◽  
Vol 88 (5) ◽  
Author(s):  
Mariya I. Goncheva ◽  
Ronald S. Flannagan ◽  
David E. Heinrichs
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Metabolic Regulation ◽  
De Novo ◽  
Purine Biosynthesis ◽  
Mammalian Host ◽  
Cell Binding ◽  
Intracellular Growth ◽  
Content Type ◽  
De Novo Purine Biosynthesis

ABSTRACT Staphylococcus aureus is a noted human and animal pathogen. Despite decades of research on this important bacterium, there are still many unanswered questions regarding the pathogenic mechanisms it uses to infect the mammalian host. This can be attributed to it possessing a plethora of virulence factors and complex virulence factor and metabolic regulation. PurR, the purine biosynthesis regulator, was recently also shown to regulate virulence factors in S. aureus, and mutations in purR result in derepression of fibronectin binding proteins (FnBPs) and extracellular toxins, required for a so-called hypervirulent phenotype. Here, we show that hypervirulent strains containing purR mutations can be attenuated with the addition of purine biosynthesis mutations, implicating the necessity for de novo purine biosynthesis in this phenotype and indicating that S. aureus in the mammalian host experiences purine limitation. Using cell culture, we showed that while purR mutants are not altered in epithelial cell binding, compared to that of wild-type (WT) S. aureus, purR mutants have enhanced invasion of these nonprofessional phagocytes, consistent with the requirement of FnBPs for invasion of these cells. This correlates with purR mutants having increased transcription of fnb genes, resulting in higher levels of surface-exposed FnBPs to promote invasion. These data provide important contributions to our understanding of how the pathogenesis of S. aureus is affected by sensing of purine levels during infection of the mammalian host.

In Silico Structure Modeling and Molecular Docking Analysis of Phosphoribosyl Pyrophosphate Amidotransferase (PPAT) with Antifolate Inhibitors

2019 ◽  
Vol 19 (5) ◽  
pp. 408-416 ◽  
Author(s):  
Nousheen Bibi ◽  
Zahida Parveen ◽  
Muhammad Sulaman Nawaz ◽  
Mohammad Amjad Kamal
Keyword(s):  
Hydrogen Bonding ◽  
Molecular Docking ◽  
Active Site ◽  
Electrostatic Interactions ◽  
De Novo ◽  
Cancer Therapeutics ◽  
Purine Biosynthesis ◽  
Biosynthesis Pathway ◽  
Phosphoribosyl Pyrophosphate ◽  
De Novo Purine Biosynthesis

Background: Cancer remains one of the most serious disease worldwide. Robust metabolism is the hallmark of cancer. PPAT (phosphoribosyl pyrophosphate amidotransferase) catalyzes the first committed step of de novo purine biosynthesis. Hence PPAT, the key regulatory spot in De novo purine nucleotide biosynthesis, is an attractive and credible drug target for leukemia and other cancer therapeutics. Objective: In the present study, detailed computational analysis has been performed for PPAT protein, the key enzyme in de novo purine biosynthesis which is inhibited by many folate derivatives, hence we aimed to investigate and gauge the inhibitory effect of antifolate derivatives; lomexterol (LTX) methotrexate (LTX), and pipretixin (PTX) with human PPAT to effectively capture and inhibit De novo purine biosynthesis pathway. Methods: The sequence to structure computational approaches followed by molecular docking experiments was performed to gain insight into the inhibitory mode, binding orientation and binding affinities of selected antifolate derivatives against important structural features of PPAT. Results: Results indicated a strong affinity of antifolate inhibitors for the conserved active site of PPAT molecule encompassing a number of hydrophobic, hydrogen bonding, Vander Waals and electrostatic interactions. Results: Results indicated a strong affinity of antifolate inhibitors for the conserved active site of PPAT molecule encompassing a number of hydrophobic, hydrogen bonding, Vander Waals and electrostatic interactions. Conclusion: Conclusively, the strong physical interaction of selected antifolate inhibitors with human PPAT suggests the selective inhibition of De novo purine biosynthesis pathway by antifolate derivatives towards cancer therapeutics.

Sign in / Sign up

Export Citation Format

Share Document