A thermodynamic bottleneck in the TCA cycle contributes to acetate overflow in .

During aerobic growth, relies on acetate overflow metabolism, a process where glucose is incompletely oxidized to acetate, for its bioenergetic needs. Acetate is not immediately captured as a carbon source and is excreted as waste by cells. The underlying factors governing acetate overflow in have not been identified.

Tissue niche influences immune and metabolic profiles to Staphylococcus aureus biofilm infection.

Infection is a devastating post-surgical complication, often requiring additional procedures and prolonged antibiotic therapy. This is especially relevant for craniotomy and prosthetic joint infections (PJI), both of which are characterized by biofilm formation on the bone or implant surface, respectively, with S. aureus representing a primary cause.

Aconitate decarboxylase 1 mediates the acute airway inflammatory response to environmental exposures.

Background: Environmental lipopolysaccharide (LPS) and microbial component-enriched organic dusts cause significant lung disease. These environmental exposures induce the recruitment and activation of distinct lung monocyte/macrophage subpopulations involved in disease pathogenesis. Aconitate decarboxylase 1 () was one of the most upregulated genes following LPS (vs.

Selective host autophagy is induced during the intracellular parasite infection controlling amino acid levels.

Unlabelled: a widespread parasite, has the ability to infect nearly any nucleated cell in warm-blooded vertebrates. It is estimated that around 2 billion people globally have been infected by this pathogen. Although most healthy individuals can effectively control parasite replication, certain parasites may evade the immune response, establishing cysts in the brain that are refractory to the immune system and resistant to available drugs.

An optimized artificial blood feeding assay to study tick cuticle biology.

Ticks, ectoparasitic arachnids, are prominent disease vectors impacting both humans and animals. Their unique blood-feeding phase involves significant abdominal cuticle expansion, sharing certain similarities with insects. However, vital aspects, including the mechanisms of cuticle expansion, changes in cuticular protein composition, chitin synthesis, and cuticle function, remain poorly understood.

Granulocytic myeloid-derived suppressor cell activity during biofilm infection is regulated by a glycolysis/HIF1a axis.

Staphylococcus aureus is a leading cause of biofilm-associated prosthetic joint infection (PJI). A primary contributor to infection chronicity is an expansion of granulocytic myeloid-derived suppressor cells (G-MDSCs), which are critical for orchestrating the antiinflammatory biofilm milieu. Single-cell sequencing and bioinformatic metabolic algorithms were used to explore the link between G-MDSC metabolism and S.

Glutamatedependent arginine biosynthesis requires the inactivation of , and in .

Genome sequencing has demonstrated that encodes arginine biosynthetic genes synthesizing proteins that mediate arginine biosynthesis using glutamate as a substrate. Paradoxically, however, does not grow in a defined, glutamate-replete medium lacking arginine and glucose (CDM-R). Studies from our laboratory have found that specific mutations are selected by that facilitate growth in CDM-R.

counters organic acid anion-mediated inhibition of peptidoglycan cross-linking through robust alanine racemase activity.

Weak organic acids are commonly found in host niches colonized by bacteria, and they can inhibit bacterial growth as the environment becomes acidic. This inhibition is often attributed to the toxicity resulting from the accumulation of high concentrations of organic anions in the cytosol, which disrupts cellular homeostasis. However, the precise cellular targets that organic anions poison and the mechanisms used to counter organic anion intoxication in bacteria have not been elucidated.

Metabolic diversity of human macrophages: potential influence on intracellular survival.

is a leading cause of medical device-associated biofilm infections. This is influenced by the ability of biofilm to evade the host immune response, which is partially driven by the anti-inflammatory cytokine interleukin-10 (IL-10). Here, we show that treatment of human monocyte-derived macrophages (HMDMs) with IL-10 enhanced biofilm formation, suggesting that macrophage anti-inflammatory programming likely plays an important role during the transition from planktonic to biofilm growth.

Host autophagy is exploited by the intracellular parasite to enhance amino acids levels.

Unlabelled: a widespread parasite, has the ability to infect nearly any nucleated cell in warm-blooded vertebrates. It is estimated that around 2 billion people globally have been infected by this pathogen. Although most healthy individuals can effectively control parasite replication, certain parasites may evade the immune response, establishing cysts in the brain that are refractory to the immune system and resistance to available drugs.

A critical role for staphylococcal nitric oxide synthase in controlling flavohemoglobin toxicity.

Most coagulase-negative staphylococcal species, including the opportunistic pathogen Staphylococcus epidermidis, struggle to maintain redox homeostasis and grow under nitrosative stress. Under these conditions, growth can only resume once nitric oxide (NO) is detoxified by the flavohemoglobin Hmp. Paradoxically, S.

Metabolic reprogramming and altered cell envelope characteristics in a pentose phosphate pathway mutant increases MRSA resistance to β-lactam antibiotics.

Central metabolic pathways control virulence and antibiotic resistance, and constitute potential targets for antibacterial drugs. In Staphylococcus aureus the role of the pentose phosphate pathway (PPP) remains largely unexplored. Mutation of the 6-phosphogluconolactonase gene pgl, which encodes the only non-essential enzyme in the oxidative phase of the PPP, significantly increased MRSA resistance to β-lactam antibiotics, particularly in chemically defined media with physiologically-relevant concentrations of glucose, and reduced oxacillin (OX)-induced lysis.

Metabolic reprogramming and flux to cell envelope precursors in a pentose phosphate pathway mutant increases MRSA resistance to β-lactam antibiotics.

Unlabelled: Central metabolic pathways controls virulence and antibiotic resistance, and constitute potential targets for antibacterial drugs. In the role of the pentose phosphate pathway (PPP) remains largely unexplored. Mutation of the 6-phosphogluconolactonase gene which encodes the only non-essential enzyme in the oxidative phase of the PPP, significantly increased MRSA resistance to β-lactam antibiotics, particularly in chemically defined media with glucose, and reduced oxacillin (OX)-induced lysis.

Role of Staphylococcus aureus Formate Metabolism during Prosthetic Joint Infection.

Biofilms are bacterial communities characterized by antibiotic tolerance. Staphylococcus aureus is a leading cause of biofilm infections on medical devices, including prosthetic joints, which represent a significant health care burden. The major leukocyte infiltrate associated with S.

PGC-1β and ERRα Promote Glutamine Metabolism and Colorectal Cancer Survival via Transcriptional Upregulation of PCK2.

Background: Previous studies have shown that Peroxisome Proliferator-Activated Receptor Gamma, Coactivator 1 Beta (PGC-1β) and Estrogen-Related Receptor Alpha (ERRα) are over-expressed in colorectal cancer and promote tumor survival.

Methods: In this study, we use immunoprecipitation of epitope tagged endogenous PGC-1β and inducible PGC-1β mutants to show that amino acid motif LRELL on PGC-1β is responsible for the physical interaction with ERRα and promotes ERRα mRNA and protein expression. We use RNAsequencing to determine the genes regulated by both PGC-1β & ERRα and find that mitochondrial Phosphoenolpyruvate Carboxykinase 2 (PCK2) is the gene that decreased most significantly after depletion of both genes.

Transient Glycolytic Complexation of Arsenate Enhances Resistance in the Enteropathogen Vibrio cholerae.

The ubiquitous presence of toxic arsenate (As) in the environment has raised mechanisms of resistance in all living organisms. Generally, bacterial detoxification of As relies on its reduction to arsenite (As) by ArsC, followed by the export of As by ArsB. However, how pathogenic species resist this metalloid remains largely unknown.

Interplay of CodY and CcpA in Regulating Central Metabolism and Biofilm Formation in Staphylococcus aureus.

Staphylococcus aureus is a medically important pathogen with high metabolic versatility allowing it to infect various niches within a host. S. aureus utilizes two major transcriptional regulators, namely, CodY and CcpA, to remodel metabolic and virulence gene expression in response to changing environmental conditions.

Catabolic Ornithine Carbamoyltransferase Activity Facilitates Growth of Staphylococcus aureus in Defined Medium Lacking Glucose and Arginine.

Previous studies have found that arginine biosynthesis in Staphylococcus aureus is repressed via carbon catabolite repression (CcpA), and proline is used as a precursor. Unexpectedly, however, robust growth of S. aureus is not observed in complete defined medium lacking both glucose and arginine (CDM-R).

The Staphylococcus aureus CidA and LrgA Proteins Are Functional Holins Involved in the Transport of By-Products of Carbohydrate Metabolism.

The Staphylococcus aureus and operons encode members of a well-conserved family of proteins thought to be involved in programmed cell death (PCD). Based on the structural similarities that CidA and LrgA share with bacteriophage holins, we have hypothesized that these proteins function by forming pores within the cytoplasmic membrane. To test this, we utilized a "lysis cassette" system that demonstrated the abilities of the and genes to support bacteriophage endolysin-induced cell lysis.

Staphylococcal ClpXP protease targets the cellular antioxidant system to eliminate fitness-compromised cells in stationary phase.

The transition from growth to stationary phase is a natural response of bacteria to starvation and stress. When stress is alleviated and more favorable growth conditions return, bacteria resume proliferation without a significant loss in fitness. Although specific adaptations that enhance the persistence and survival of bacteria in stationary phase have been identified, mechanisms that help maintain the competitive fitness potential of nondividing bacterial populations have remained obscure.

Accumulation of Succinyl Coenzyme A Perturbs the Methicillin-Resistant (MRSA) Succinylome and Is Associated with Increased Susceptibility to Beta-Lactam Antibiotics.

Penicillin binding protein 2a (PBP2a)-dependent resistance to β-lactam antibiotics in methicillin-resistant Staphylococcus aureus (MRSA) is regulated by the activity of the tricarboxylic acid (TCA) cycle via a poorly understood mechanism. We report that mutations in and , but not other TCA cycle enzymes, negatively impact β-lactam resistance without changing PBP2a expression. Increased intracellular levels of succinyl coenzyme A (succinyl-CoA) in the mutant significantly perturbed lysine succinylation in the MRSA proteome.

Staphylococcus aureus ATP Synthase Promotes Biofilm Persistence by Influencing Innate Immunity.

is a major cause of prosthetic joint infection (PJI), which is characterized by biofilm formation. biofilm skews the host immune response toward an anti-inflammatory profile by the increased recruitment of myeloid-derived suppressor cells (MDSCs) that attenuate macrophage proinflammatory activity, leading to chronic infection. A screen of the Nebraska Transposon Mutant Library identified several hits in the ATP synthase operon that elicited a heightened inflammatory response in macrophages and MDSCs, including , which encodes the alpha subunit of ATP synthase.

Lactate production by Staphylococcus aureus biofilm inhibits HDAC11 to reprogramme the host immune response during persistent infection.

Staphylococcus aureus is a leading cause of biofilm-associated prosthetic joint infection (PJI), resulting in considerable disability and prolonged treatment. It is known that host leukocyte IL-10 production is required for S. aureus biofilm persistence in PJI.

An integrated computational and experimental study to investigate Staphylococcus aureus metabolism.

Staphylococcus aureus is a metabolically versatile pathogen that colonizes nearly all organs of the human body. A detailed and comprehensive knowledge of staphylococcal metabolism is essential to understand its pathogenesis. To this end, we have reconstructed and experimentally validated an updated and enhanced genome-scale metabolic model of S.

Identification of the main glutamine and glutamate transporters in Staphylococcus aureus and their impact on c-di-AMP production.

A Staphylococcus aureus strain deleted for the c-di-AMP cyclase gene dacA is unable to survive in rich medium unless it acquires compensatory mutations. Previously identified mutations were in opuD, encoding the main glycine-betaine transporter, and alsT, encoding a predicted amino acid transporter. Here, we show that inactivation of OpuD restores the cell size of a dacA mutant to near wild-type (WT) size, while inactivation of AlsT does not.