A5070237784- Antibiotic Resistance in Bacteria
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Fungal and yeast genetics research
- Endoplasmic Reticulum Stress and Disease
- Bacterial Genetics and Biotechnology
- Antifungal resistance and susceptibility
- Autophagy in Disease and Therapy
- Cancer therapeutics and mechanisms
- Microbial Inactivation Methods
- Escherichia coli research studies
- Antibiotics Pharmacokinetics and Efficacy
- Microbial Natural Products and Biosynthesis
- Fungal Infections and Studies
- Studies on Chitinases and Chitosanases
- Click Chemistry and Applications
- Plant-Microbe Interactions and Immunity
- Peptidase Inhibition and Analysis
- Cell death mechanisms and regulation
- RNA regulation and disease
- Enzyme-mediated dye degradation
- Electrochemical sensors and biosensors
- Mycotoxins in Agriculture and Food
- Fungal Biology and Applications
- Lung Cancer Treatments and Mutations
Novartis (United States)
2012-2022
Novartis (Switzerland)
2015
University of Cincinnati Medical Center
2006-2013
Sabin Vaccine Institute
2006-2010
University of Cincinnati
2008-2009
Filamentous fungi rely heavily on the secretory pathway, both for delivery of cell wall components to hyphal tip and production secretion extracellular hydrolytic enzymes needed support growth polymeric substrates. Increased demand system exerts stress endoplasmic reticulum (ER), which is countered by activation a coordinated response pathway termed unfolded protein (UPR). To determine contribution UPR virulence filamentous fungal pathogen Aspergillus fumigatus, we disrupted hacA gene,...
Endoplasmic reticulum (ER) stress is a condition in which the protein folding capacity of ER becomes overwhelmed by an increased demand for secretion or exposure to compounds that disrupt homeostasis. In yeast and other fungi, accumulation unfolded proteins detected ER-transmembrane sensor IreA/Ire1, responds cleaving intron from downstream cytoplasmic mRNA HacA/Hac1, allowing translation transcription factor coordinates series adaptive responses are collectively known as response (UPR)....
ABSTRACT Autophagy is the major cellular pathway for bulk degradation of cytosolic material and required to maintain viability under starvation conditions. To determine contribution autophagy stress responses in filamentous fungus Aspergillus fumigatus , we disrupted A. atg1 gene, encoding a serine/threonine kinase autophagy. The ΔAf mutant showed abnormal conidiophore development reduced conidiation, but defect could be bypassed by increasing nitrogen content medium. When transferred...
Summary We have examined the contribution of metacaspases to growth and stress response opportunistic human mould pathogen, Aspergillus fumigatus , based on increasing evidence implicating yeast metacaspase Yca1p in apoptotic‐like programmed cell death. Single metacaspase‐deficient mutants were constructed by targeted disruption each two genes A. casA casB a mutant, Δ /Δ was disrupting both genes. Stationary phase cultures wild‐type associated with appearance typical markers apoptosis,...
ABSTRACT Lipid A on the Gram-negative outer membrane (OM) is synthesized in cytoplasm by Lpx pathway and translocated to OM Lpt pathway. Some Acinetobacter baumannii strains can tolerate complete loss of lipopolysaccharide (LPS) resulting from inactivation early LPS genes such as lpxC . Here, we characterized a mutant deleted for lptD , which encodes an protein that mediates final translocation fully OM. Cells lacking had growth defect comparable deletion under conditions tested but were...
The genome of Aspergillus fumigatus encodes two isoforms the catalytic subunit cAMP-dependent Protein Kinase (PKA). Although deletion class I isoform, pkaC1, leads to an attenuation virulence, function II subunit, PkaC2, was previously uninvestigated. In this report, we demonstrate that both act in concert support various physiologic processes promote virulence pathogen. Whereas pkaC1 and pkaC2 single-deletion mutants display wild-type conidial germination, a double-deletion mutant is...
The filamentous fungal pathogen Aspergillus fumigatus secretes hydrolytic enzymes to acquire nutrients from host tissues. production of these exerts stress on the endoplasmic reticulum (ER), which is alleviated by two responses: unfolded protein response (UPR), adjusts folding capacity ER, and ER-associated degradation (ERAD), disposes proteins that fail fold correctly. In this study, we examined contribution integrated pathways growth virulence A. fumigatus, focusing ERAD DerA master...
The lipid A moiety of lipopolysaccharide (LPS) is the main constituent outer leaflet Gram-negative bacterial membrane (OM) and essential in many pathogens. An exception Acinetobacter baumannii ATCC 19606, where mutants lacking enzymes occurring early biosynthesis (LpxA, LpxC or LpxD), correspondingly LPS, can grow. In contrast, we show here that LpxH, an enzyme occurs downstream LpxD biosynthetic pathway, for growth this strain. Multiple attempts to disrupt lpxH on genome were unsuccessful,...
ABSTRACT High-throughput phenotypic screening against the yeast Saccharomyces cerevisiae revealed a series of triazolopyrimidine-sulfonamide compounds with broad-spectrum antifungal activity, no significant cytotoxicity, and low protein binding. To elucidate target this series, we have applied chemogenomic profiling approach using S. deletion collection. All yielded highly similar profiles that suggested acetolactate synthase (Ilv2p, which catalyzes first common step in branched-chain amino...
Since their discovery over 5 decades ago, quinolone antibiotics have found enormous success as broad spectrum agents that exert activity through dual inhibition of bacterial DNA gyrase and topoisomerase IV. Increasing rates resistance, driven largely by target-based mutations in the GyrA/ParC resistance determining region, eroded utility threaten future use this vital class antibiotics. Herein we describe optimization a series 4-(aminomethyl)quinolin-2(1H)-ones, exemplified 34, inhibit IV...
Acinetobacter baumannii ATCC 19606 can grow without lipid A, the major component of lipooligosaccharide. However, we previously reported that depletion LpxH (the fourth enzyme in A biosynthetic pathway) prevented growth this strain due to toxic accumulation pathway intermediates. Here, explored whether a similar phenomenon occurred with LpxK, kinase phosphorylates disaccharide 1-monophosphate (DSMP) at 4' position yield IVA. An A. derivative LpxK expression under control an isopropyl...
Mycograb C28Y is a recombinant human antibody fragment thought to target HSP-90 and potentiate amphotericin B (AMB). Absence of in vivo efficacy led us reevaluate its vitro activity. Interactions between AMB were investigated using checkerboard design. Addition or various unrelated proteins, including serum, resulted similar decreases the MIC AMB. Potentiation by appears be nonspecific protein effect.
ABSTRACT Proteins that are destined for release outside the eukaryotic cell, insertion into plasma membrane, or delivery to intracellular organelles processed and folded in endoplasmic reticulum (ER). An imbalance between level of nascent proteins entering ER organelle's ability manage load results accumulation unfolded proteins. Terminally disposed by ER-associated degradation (ERAD), a pathway transports aberrant across membrane cytosol proteasomal degradation. The ERAD was targeted mold...
Herein, we describe the discovery and optimization of a novel series that inhibits bacterial DNA gyrase topoisomerase IV via binding to, stabilization of, cleavage complexes. Optimization this led to identification compound 25, which has potent activity against Gram-positive bacteria, favorable in vitro safety profile, excellent vivo pharmacokinetic properties. Compound 25 was found be efficacious fluoroquinolone-sensitive Staphylococcus aureus infection mouse thigh model at lower doses than...
Systemic life-threatening fungal infections represent a significant unmet medical need. Cell-based, phenotypic screening can be an effective means of discovering potential novel antifungal compounds, but it does not address target identification, normally required for compound optimization by medicinal chemistry. Here, we demonstrate combination screening, genetic, and biochemical approaches to identify characterize compounds. We isolated set non-azole compounds which no or mechanism action...
Tight coordination of inner and outer membrane biosynthesis is very important in Gram-negative bacteria. Biosynthesis the lipid A moiety lipopolysaccharide, which comprises leaflet has garnered interest for antibacterial discovery. In particular, several potent inhibitors LpxC (the first committed step pathway) are described. Here we show that serial passaging Klebsiella pneumoniae increasing levels an inhibitor yielded mutants grew only presence inhibitor. These strains had mutations fabZ...
AbstractNutrient limitation is one of the most common forms stress encountered by microorganisms in environment. Surviving this depends upon a number integrated responses, important which autophagy. When filamentous fungus Aspergillus fumigatus becomes nutrient deprived it undergoes two processes: developmental pathway for asexual sporulation (conidiation), and foraging response that promotes migration hyphal tips into new substrate. To determine contribution autophagy to these functions, we...
Acinetobacter baumannii ATCC 19606 can grow without lipooligosaccharide (LOS). Lack of LOS result from disruption the early lipid A biosynthetic pathway genes lpxA, lpxC or lpxD. Although itself is not essential for growth A. 19606, it was previously shown that depletion enzyme LpxK in cells inhibited due to toxic accumulation intermediates. Growth LpxK-depleted restored by chemical inhibition biosynthesis using CHIR-090 (LpxC) and fatty acid cerulenin (FabB/F) pyridopyrimidine...
Aspergillus fumigatus is an important opportunistic fungal pathogen that responsible for high mortality rates in the immunosuppressed population. CgrA, A. ortholog of a Saccharomyces cerevisiae nucleolar protein involved ribosome biogenesis, contributes to virulence this fungus by supporting rapid growth at 37 degrees C. To determine how CgrA affects biogenesis fumigatus, polysome profile and ribosomal subunit analyses were performed on both wild-type DeltacgrA mutant. The loss was...
CUO246, a novel DNA gyrase/topoisomerase IV inhibitor, is active in vitro against broad range of Gram-positive, fastidious Gram-negative, and atypical bacterial pathogens retains activity quinolone-resistant strains circulation. The frequency selection for single step mutants wild-type S. aureus with reduced susceptibility to CUO246 was <4.64 × 10-9 at 4× 8× MIC remained low when using an isogenic QRDR mutant (<5.24 MIC). Biochemical assays indicated that had potent inhibitory both gyrase...