In methicillin-sensitive (MSSA), the tricarboxylic acid (TCA) cycle is known to negatively regulate production of the major biofilm-matrix exopolysaccharide, PIA/PNAG. However, methicillin-resistant (MRSA) produce a primarily proteinaceous biofilm matrix, and contribution of the TCA-cycle therein remains unclear. Utilizing USA300-JE2 Tn-mutants (NARSA) in genes encoding TCA- and urea cycle enzymes for transduction into a prolific biofilm-forming USA300 strain (UAS391-Ery), we studied the contribution of the TCA- and urea cycle and of proteins, eDNA and PIA/PNAG, to the matrix. Genes targeted in the urea cycle encoded argininosuccinate lyase and arginase (::Tn and ::Tn), and in the TCA-cycle encoded succinyl-CoA synthetase, succinate dehydrogenase, aconitase, isocitrate dehydrogenase, fumarate hydratase class II, and citrate synthase II (::Tn, ::Tn, ::Tn, ::Tn, ::Tn and ::Tn). Biofilm formation was significantly decreased under no flow and flow conditions by Tn, Tn and Tn (range OD 0.374-0.667; integrated densities 2.065-4.875) compared to UAS391-Ery (OD 0.814; integrated density 10.676) ( ≤ 0.008). Cellular and matrix stains, enzymatic treatment (Proteinase K, DNase I), and reverse-transcriptase PCR-based gene-expression analysis of fibronectin-binding proteins and the staphylococcal accessory regulator on pre-formed UAS391-Ery and Tn-mutant biofilms showed: (i) < 1% PIA/PNAG in the proteinaceous/eDNA matrix; (ii) increased proteins under no flow and flow in the matrix of Tn mutant biofilms (on average 50 and 51 (±11)%) compared to UAS391-Ery (on average 22 and 25 (±4)%) ( < 0.001); and (iii) down- and up-regulation of and , respectively, in Tn-mutants compared to UAS391-Ery (0.62-, 0.57-, and 2.23-fold on average). In conclusion, we show that the biofilm matrix of MRSA-USA300 and the corresponding Tn mutants is PIA/PNAG-independent and are mainly composed of proteins and eDNA. The primary impact of TCA-cycle inactivation was on the protein component of the biofilm matrix of MRSA-USA300.
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http://dx.doi.org/10.3390/microorganisms6040113 | DOI Listing |
Pharmaceutics
January 2025
Department of Pharmacy, "Federico II" University of Naples, 80131 Naples, Italy.
Arginase (ARG) is a binuclear manganese-containing metalloenzyme that can convert L-arginine to L-ornithine and urea and plays a key role in the urea cycle. It also mediates different cellular functions and processes such as proliferation, senescence, apoptosis, autophagy, and inflammatory responses in various cell types. In mammals, there are two isoenzymes, ARG-1 and ARG-2; they are functionally similar, but their coding genes, tissue distribution, subcellular localization, and molecular regulation are distinct.
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January 2025
Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia.
Macular telangiectasia type 2 (MacTel) is a slowly progressive macular disorder that is often diagnosed late due to the gradual onset of vision loss. Recent advances in diagnostic techniques have facilitated earlier detection and have shown that MacTel is more common than initially thought. The disease is genetically complex, and multiple variants contribute incrementally to the overall risk.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Institute of Molecular Biology, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. Bl. 21, 1113 Sofia, Bulgaria.
Replication forks encounter various impediments, which induce fork stalling and threaten genome stability, yet the precise dynamics of fork stalling and restart at the single-cell level remain elusive. Herein, we devise a live-cell microscopy-based approach to follow hydroxyurea-induced fork stalling and subsequent restart at 30 s resolution. We measure two distinct processes during fork stalling.
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January 2025
Department of Urology, Renmin Hospital of Wuhan University, Wuhan 430060, China.
Acute kidney injury (AKI) and chronic kidney disease (CKD) represent two frequently observed clinical conditions. AKI is characterized by an abrupt decrease in glomerular filtration rate (GFR), generally associated with elevated serum creatinine (sCr), blood urea nitrogen (BUN), and electrolyte imbalances. This condition usually persists for approximately a week, causing a transient reduction in kidney function.
View Article and Find Full Text PDFWaste Manag
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Luzhou LaoJiao Co., Ltd, Luzhou 646699 China.
Solid-state fermentation of lignocellulosic waste to produce feed protein is a means of realising solid waste. However, low efficiency and susceptibility to microbial contamination remain significant challenges in feed protein production through room-temperature solid-state fermentation. In this study, thermophilic microbiomes were enriched.
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