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Yang H, Zhang X, Zhu Y, Zhang B, Fan J, Zhao H, Zhang B. Utilization of Peptidoglycans from Lactic Acid Bacterial Cell Walls for the Mitigation of Acrylamide and 5-Hydroxymethylfurfural. TOXICS 2024; 12:380. [PMID: 38922060 PMCID: PMC11209152 DOI: 10.3390/toxics12060380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 05/14/2024] [Accepted: 05/21/2024] [Indexed: 06/27/2024]
Abstract
Acrylamide (AA) and 5-hydroxymethylfurfural (HMF), which are potentially carcinogenic to humans, are often produced during the hot processing of foods. This study first used a molecular docking model to simulate the binding behavior of four lactic acid bacteria peptidoglycans (PGNs) to AA/HMF, and the binding rate of LAB-based PGNs to AA/HMF was evaluated in vitro. In silico results show that interaction energy is the driving force responsible for the adsorption of LAB-derived PGNs to AA/HMF. In vitro results showed that the PGN of B. lactis B1-04 bound the most AA (28.7%) and HMF (48.0%), followed by L. acidophilus NCFM, B. breve CICC 6079, and L. plantarum CICC 22135. Moreover, an AA/HMF-bound layer on the cell surface of B. lactis B1-04 was observed via AFM and SEM due to adsorption. XPS analysis indicated the removal rate of AA/HMF by selected strains was positively correlated with the proportion of C-O, C=O, and N-H groups of PGNs. The atoms O1, O2, O3, O4, N1, N2, N3, H1, and H2 are involved in the adsorption of LAB-based PGNs to AA/HMF. Thus, the PGNs derived from these four Lactobacillus strains can be regarded as natural adsorbents for the binding of AA/HMF.
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Affiliation(s)
| | | | | | | | | | - Hongfei Zhao
- Beijing Key Laboratory of Forest Food Processing and Safety, College of Biological Science & Biotechnology, Beijing Forestry University, Beijing 100083, China; (H.Y.); (X.Z.); (Y.Z.); (B.Z.); (J.F.)
| | - Bolin Zhang
- Beijing Key Laboratory of Forest Food Processing and Safety, College of Biological Science & Biotechnology, Beijing Forestry University, Beijing 100083, China; (H.Y.); (X.Z.); (Y.Z.); (B.Z.); (J.F.)
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Panda S, Jayasinghe YP, Shinde DD, Bueno E, Stastny A, Bertrand BP, Chaudhari SS, Kielian T, Cava F, Ronning DR, Thomas VC. Staphylococcus aureus counters organic acid anion-mediated inhibition of peptidoglycan cross-linking through robust alanine racemase activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.15.575639. [PMID: 38293037 PMCID: PMC10827132 DOI: 10.1101/2024.01.15.575639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
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. Here, we utilize acetic acid, a weak organic acid abundantly found in the gut to investigate its impact on the growth of Staphylococcus aureus. We demonstrate that acetate anions bind to and inhibit d-alanyl-d-alanine ligase (Ddl) activity in S. aureus. Ddl inhibition reduces intracellular d-alanyl-d-alanine (d-Ala-d-Ala) levels, compromising staphylococcal peptidoglycan cross-linking and cell wall integrity. To overcome the effects of acetate-mediated Ddl inhibition, S. aureus maintains a high intracellular d-Ala pool through alanine racemase (Alr1) activity and additionally limits the flux of d-Ala to d-glutamate by controlling d-alanine aminotransferase (Dat) activity. Surprisingly, the modus operandi of acetate intoxication in S. aureus is common to multiple biologically relevant weak organic acids indicating that Ddl is a conserved target of small organic anions. These findings suggest that S. aureus may have evolved to maintain high intracellular d-Ala concentrations, partly to counter organic anion intoxication.
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Affiliation(s)
- Sasmita Panda
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Yahani P Jayasinghe
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Dhananjay D Shinde
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Emilio Bueno
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Center for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umea SE-90187, Sweden
| | - Amanda Stastny
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Blake P Bertrand
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Sujata S Chaudhari
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Tammy Kielian
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Center for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umea SE-90187, Sweden
| | - Donald R Ronning
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Vinai C Thomas
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, USA
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Mishra NR, Sharma AD, Gargvanshi S, Gutheil WG. Deconvolution of multichannel LC-MS/MS chromatograms of glucosamine-phosphates: Evidence of a GlmS regulatory difference between Staphylococcus aureus and Enterococcus faecium. TALANTA OPEN 2023; 8:100241. [PMID: 38187186 PMCID: PMC10769159 DOI: 10.1016/j.talo.2023.100241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024] Open
Abstract
Resolving isomeric analytes is challenging given their physical similarity - making chromatographic resolution difficult, and their identical masses - making simple mass resolution impossible. MS/MS data provides a means to resolve isomeric analytes if their MS/MS intensity profiles are sufficiently different. Glucosamine-6-phosphate (GlcN-6P) and glucosamine-1-phosphate (GlcN-1P) are early bacterial cell wall intermediates. These and other isomeric hexosamine-phosphates are highly polar and unretained on reverse-phase chromatography media. Three commercially available hexosamine-phosphate standards (GlcN-6P, GlcN-1P, and GalN-1P) were derivatized with octanoic anhydride, and chromatographic conditions were established to resolve these analytes on C18 columns. GlcN-1P and GalN-1P overlapped chromatographically under all tested chromatography conditions. Three MS/MS fragments (79, 97, and 199 m/z) were common to all three commercially available hexosamine-phosphates. Intensity ratios of the three MS/MS fragments from these three hexosamine-phosphate standards were used to deconvolute mixture chromatograms of these standards by non-negative linear regression. This approach allowed the complete resolution of these analytes. The chromatographically overlapping GlcN-1P and GalN-1P, which shared similar but modestly different MS/MS intensity profiles, were fully resolved with this non-negative deconvolution approach. This approach was then applied to MRSA, VSE, and VRE bacterial extracts before and after exposure to vancomycin. This demonstrated a substantial (3-fold) increase in GlcN-6P in vancomycin-treated MRSA samples but not in vancomycin-treated VSE or VRE samples. These observations appear to localize previously observed differences between MRSA and VRE/VSE peptidoglycan biosynthesis regulation to GlmS, which synthesizes GlcN-6P and is the product of a regulatory ribozyme sensitive to the levels of GlcN-6P.
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Affiliation(s)
| | | | - Shivani Gargvanshi
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, 64108, USA
| | - William G. Gutheil
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, 64108, USA
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Ayon NJ. High-Throughput Screening of Natural Product and Synthetic Molecule Libraries for Antibacterial Drug Discovery. Metabolites 2023; 13:625. [PMID: 37233666 PMCID: PMC10220967 DOI: 10.3390/metabo13050625] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 04/29/2023] [Accepted: 05/01/2023] [Indexed: 05/27/2023] Open
Abstract
Due to the continued emergence of resistance and a lack of new and promising antibiotics, bacterial infection has become a major public threat. High-throughput screening (HTS) allows rapid screening of a large collection of molecules for bioactivity testing and holds promise in antibacterial drug discovery. More than 50% of the antibiotics that are currently available on the market are derived from natural products. However, with the easily discoverable antibiotics being found, finding new antibiotics from natural sources has seen limited success. Finding new natural sources for antibacterial activity testing has also proven to be challenging. In addition to exploring new sources of natural products and synthetic biology, omics technology helped to study the biosynthetic machinery of existing natural sources enabling the construction of unnatural synthesizers of bioactive molecules and the identification of molecular targets of antibacterial agents. On the other hand, newer and smarter strategies have been continuously pursued to screen synthetic molecule libraries for new antibiotics and new druggable targets. Biomimetic conditions are explored to mimic the real infection model to better study the ligand-target interaction to enable the designing of more effective antibacterial drugs. This narrative review describes various traditional and contemporaneous approaches of high-throughput screening of natural products and synthetic molecule libraries for antibacterial drug discovery. It further discusses critical factors for HTS assay design, makes a general recommendation, and discusses possible alternatives to traditional HTS of natural products and synthetic molecule libraries for antibacterial drug discovery.
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Affiliation(s)
- Navid J Ayon
- Chemistry of Life Processes Institute, Northwestern University, Evanston, IL 60208, USA
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Centeno-Leija S, Espinosa-Barrera L, Velazquez-Cruz B, Cárdenas-Conejo Y, Virgen-Ortíz R, Valencia-Cruz G, Saenz RA, Marín-Tovar Y, Gómez-Manzo S, Hernández-Ochoa B, Rocha-Ramirez LM, Zataraín-Palacios R, Osuna-Castro JA, López-Munguía A, Serrano-Posada H. Mining for novel cyclomaltodextrin glucanotransferases unravels the carbohydrate metabolism pathway via cyclodextrins in Thermoanaerobacterales. Sci Rep 2022; 12:730. [PMID: 35031648 PMCID: PMC8760340 DOI: 10.1038/s41598-021-04569-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/20/2021] [Indexed: 11/21/2022] Open
Abstract
Carbohydrate metabolism via cyclodextrins (CM-CD) is an uncommon starch-converting pathway that thoroughly depends on extracellular cyclomaltodextrin glucanotransferases (CGTases) to transform the surrounding starch substrate to α-(1,4)-linked oligosaccharides and cyclodextrins (CDs). The CM-CD pathway has emerged as a convenient microbial adaptation to thrive under extreme temperatures, as CDs are functional amphipathic toroids with higher heat-resistant values than linear dextrins. Nevertheless, although the CM-CD pathway has been described in a few mesophilic bacteria and archaea, it remains obscure in extremely thermophilic prokaryotes (Topt ≥ 70 °C). Here, a new monophyletic group of CGTases with an exceptional three-domain ABC architecture was detected by (meta)genome mining of extremely thermophilic Thermoanaerobacterales living in a wide variety of hot starch-poor environments on Earth. Functional studies of a representative member, CldA, showed a maximum activity in a thermoacidophilic range (pH 4.0 and 80 °C) with remarkable product diversification that yielded a mixture of α:β:γ-CDs (34:62:4) from soluble starch, as well as G3-G7 linear dextrins and fermentable sugars as the primary products. Together, comparative genomics and predictive functional analysis, combined with data of the functionally characterized key proteins of the gene clusters encoding CGTases, revealed the CM-CD pathway in Thermoanaerobacterales and showed that it is involved in the synthesis, transportation, degradation, and metabolic assimilation of CDs.
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Affiliation(s)
- Sara Centeno-Leija
- Consejo Nacional de Ciencia y Tecnología, Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico.
| | - Laura Espinosa-Barrera
- Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Beatriz Velazquez-Cruz
- Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Yair Cárdenas-Conejo
- Consejo Nacional de Ciencia y Tecnología, Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Raúl Virgen-Ortíz
- Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico
| | - Georgina Valencia-Cruz
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Avenida 25 de julio 965, Colonia Villa de San Sebastián, 28045, Colima, Colima, Mexico
| | - Roberto A Saenz
- Facultad de Ciencias, Universidad de Colima, Bernal Díaz del Castillo 340, 28045, Colima, Colima, Mexico
| | - Yerli Marín-Tovar
- Laboratorio de Bioquímica Estructural, Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa, 62210, Cuernavaca, Mexico
| | - Saúl Gómez-Manzo
- Laboratorio de Bioquímica Genética, Instituto Nacional de Pediatría, Secretaría de Salud, 04530, Mexico City, Mexico
| | - Beatriz Hernández-Ochoa
- Laboratorio de Inmunoquímica y Biología Celular, Hospital Infantil de México Federico Gómez, Secretaría de Salud, 06720, Mexico City, Mexico
| | - Luz María Rocha-Ramirez
- Unidad de Investigación en Enfermedades Infecciosas, Hospital Infantil de México Federico Gómez, Dr. Márquez No. 162, Colonia Doctores, 06720, Delegación Cuauhtémoc, Mexico
| | - Rocío Zataraín-Palacios
- Escuela de Medicina General, Universidad José Martí, Bosques del Decán 351, 28089, Colima, Colima, México
| | - Juan A Osuna-Castro
- Facultad de Ciencias Biológicas y Agropecuarias, Universidad de Colima, Autopista Colima-Manzanillo, 28100, Tecomán, Colima, Mexico
| | - Agustín López-Munguía
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa, 62210, Cuernavaca, Morelos, Mexico
| | - Hugo Serrano-Posada
- Consejo Nacional de Ciencia y Tecnología, Laboratorio de Biología Sintética, Estructural y Molecular, Laboratorio de Agrobiotecnología, Tecnoparque CLQ, Universidad de Colima, Carretera Los Limones-Loma de Juárez, 28627, Colima, Colima, Mexico.
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Susceptibility of Ocular Staphylococcus aureus to Antibiotics and Multipurpose Disinfecting Solutions. Antibiotics (Basel) 2021; 10:antibiotics10101203. [PMID: 34680784 PMCID: PMC8533015 DOI: 10.3390/antibiotics10101203] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 10/01/2021] [Accepted: 10/01/2021] [Indexed: 12/18/2022] Open
Abstract
Staphylococcus aureus is a frequent cause of ocular surface infections worldwide. Of these surface infections, those involving the cornea (microbial keratitis) are most sight-threatening. S. aureus can also cause conjunctivitis and contact lens-related non-infectious corneal infiltrative events (niCIE). The aim of this study was to determine the rates of resistance of S. aureus isolates to antibiotics and disinfecting solutions from these different ocular surface conditions. In total, 63 S. aureus strains from the USA and Australia were evaluated; 14 were from niCIE, 26 from conjunctivitis, and 23 from microbial keratitis (MK). The minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) of all the strains to ciprofloxacin, ceftazidime, oxacillin, gentamicin, vancomycin, chloramphenicol, azithromycin, and polymyxin B were determined. The MIC and MBC of the niCIE strains to contact lens multipurpose disinfectant solutions (MPDSs) was determined. All isolates were susceptible to vancomycin (100%). The susceptibility to other antibiotics decreased in the following order: gentamicin (98%), chloramphenicol (76%), oxacillin (74%), ciprofloxacin (46%), ceftazidime (11%), azithromycin (8%), and polymyxin B (8%). In total, 87% of all the isolates were multidrug resistant and 17% of the isolates from microbial keratitis were extensively drug resistant. The microbial keratitis strains from Australia were usually susceptible to ciprofloxacin (57% vs. 11%; p = 0.04) and oxacillin (93% vs. 11%; p = 0.02) compared to microbial keratitis isolates from the USA. Microbial keratitis isolates from the USA were less susceptible (55%) to chloramphenicol compared to conjunctivitis strains (95%; p = 0.01). Similarly, 75% of conjunctivitis strains from Australia were susceptible to chloramphenicol compared to 14% of microbial keratitis strains (p = 0.04). Most (93%) strains isolated from contact lens wearers were killed in 100% MPDS, except S. aureus 27. OPTI-FREE PureMoist was the most active MPDS against all strains with 35% of strains having an MIC ≤ 11.36%. There was a significant difference in susceptibility between OPTI-FREE PureMoist and Biotrue (p = 0.02). S. aureus non-infectious CIE strains were more susceptible to antibiotics than conjunctivitis strains and conjunctivitis strains were more susceptible than microbial keratitis strains. Microbial keratitis strains from Australia (isolated between 2006 and 2018) were more susceptible to antibiotics in comparison with microbial keratitis strains from the USA (isolated in 2004). Most of the strains were multidrug-resistant. There was variability in the susceptibility of contact lens isolates to MPDSs with one S. aureus strain, S. aureus 27, isolated from niCIE, in Australia in 1997 being highly resistant to all four MPDSs and three different types of antibiotics. Knowledge of the rates of resistance to antibiotics in different conditions and regions could help guide treatment of these diseases.
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Effect of Vancomycin on Cytoplasmic Peptidoglycan Intermediates and van Operon mRNA Levels in VanA-Type Vancomycin-Resistant Enterococcus faecium. J Bacteriol 2021; 203:e0023021. [PMID: 34060906 DOI: 10.1128/jb.00230-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Resistance in VanA-type vancomycin-resistant Enterococcus faecium (VREfm) is due to an inducible gene cassette encoding seven proteins (vanRSHAXYZ). This provides for an alternative peptidoglycan (PG) biosynthesis pathway whereby D-Ala-D-Ala is replaced by D-Ala-d-lactate (Lac), to which vancomycin cannot bind effectively. This study aimed to quantify cytoplasmic levels of normal and alternative pathway PG intermediates in VanA-type VREfm by liquid chromatography-tandem mass spectrometry before and after vancomycin exposure and to correlate these changes with changes in vanA operon mRNA levels measured by real-time quantitative PCR (RT-qPCR). Normal pathway intermediates predominated in the absence of vancomycin, with low levels of alternative pathway intermediates. Extended (18-h) vancomycin exposure resulted in a mixture of the terminal normal (UDP-N-acetylmuramic acid [NAM]-l-Ala-D-Glu-l-Lys-D-Ala-D-Ala [UDP-Penta]) and alternative (UDP-NAM-l-Ala-γ-D-Glu-l-Lys-D-Ala-D-Lac [UDP-Pentadepsi]) pathway intermediates (2:3 ratio). Time course analyses revealed normal pathway intermediates responding rapidly (peaking in 3 to 10 min) and alternative pathway intermediates responding more slowly (peaking in 15 to 45 min). RT-qPCR demonstrated that vanA operon mRNA transcript levels increased rapidly after exposure, reaching maximal levels in 15 min. To resolve the effect of increased van operon protein expression on PG metabolite levels, linezolid was used to block protein biosynthesis. Surprisingly, linezolid dramatically reduced PG intermediate levels when used alone. When used in combination with vancomycin, linezolid only modestly reduced alternative UDP-linked PG intermediate levels, indicating substantial alternative pathway presence before vancomycin exposure. Comparison of PG intermediate levels between VREfm, vancomycin-sensitive Enterococcus faecium, and methicillin-resistant Staphylococcus aureus after vancomycin exposure demonstrated substantial differences between S. aureus and E. faecium PG biosynthesis pathways. IMPORTANCE VREfm is highly resistant to vancomycin due to the presence of a vancomycin resistance gene cassette. Exposure to vancomycin induces the expression of genes in this cassette, which encode enzymes that provide for an alternative PG biosynthesis pathway. In VanA-type resistance, these alternative pathway enzymes replace the D-Ala-D-Ala terminus of normal PG intermediates with D-Ala-D-Lac terminated intermediates, to which vancomycin cannot bind. While the general features of this resistance mechanism are well known, the details of the choreography between vancomycin exposure, vanA gene induction, and changes in the normal and alternative pathway intermediate levels have not been described previously. This study comprehensively explores how VREfm responds to vancomycin exposure at the mRNA and PG intermediate levels.
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The Antibacterial Activity of Human Amniotic Membrane against Multidrug-Resistant Bacteria Associated with Urinary Tract Infections: New Insights from Normal and Cancerous Urothelial Models. Biomedicines 2021; 9:biomedicines9020218. [PMID: 33672670 PMCID: PMC7924402 DOI: 10.3390/biomedicines9020218] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/12/2021] [Accepted: 02/17/2021] [Indexed: 12/31/2022] Open
Abstract
Urinary tract infections (UTIs) represent a serious global health issue, especially due to emerging multidrug-resistant UTI-causing bacteria. Recently, we showed that the human amniotic membrane (hAM) could be a candidate for treatments and prevention of UPEC and Staphylococcus aureus infections. However, its role against multidrug-resistant bacteria, namely methicillin-resistant S. aureus (MRSA), extended-spectrum beta-lactamases (ESBL) producing Escherichia coli and Klebsiella pneumoniae, vancomycin-resistant Enterococci (VRE), carbapenem-resistant Acinetobacter baumannii, and Pseudomonas aeruginosa has not yet been thoroughly explored. Here, we demonstrate for the first time that the hAM homogenate had antibacterial activity against 7 out of 11 tested multidrug-resistant strains, the greatest effect was on MRSA. Using novel approaches, its activity against MRSA was further evaluated in a complex microenvironment of normal and cancerous urinary bladder urothelia. Even short-term incubation in hAM homogenate significantly decreased the number of bacteria in MRSA-infected urothelial models, while it did not affect the viability, number, and ultrastructure of urothelial cells. The hAM patches had no antibacterial activity against any of the tested strains, which further exposes the importance of the hAM preparation. Our study substantially contributes to basic knowledge on the antibacterial activity of hAM and reveals its potential to be used as an antibacterial agent against multidrug-resistant bacteria.
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c-di-AMP Accumulation Impairs Muropeptide Synthesis in Listeria monocytogenes. J Bacteriol 2020; 202:JB.00307-20. [PMID: 33020220 DOI: 10.1128/jb.00307-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 09/17/2020] [Indexed: 12/14/2022] Open
Abstract
Cyclic di-AMP (c-di-AMP) is an essential and ubiquitous second messenger among bacteria. c-di-AMP regulates many cellular pathways through direct binding to several molecular targets in bacterial cells. c-di-AMP depletion is well known to destabilize the bacterial cell wall, resulting in increased bacteriolysis and enhanced susceptibility to cell wall targeting antibiotics. Using the human pathogen Listeria monocytogenes as a model, we found that c-di-AMP accumulation also impaired cell envelope integrity. An L. monocytogenes mutant deleted for c-di-AMP phosphodiesterases (pdeA pgpH mutant) exhibited a 4-fold increase in c-di-AMP levels and several cell wall defects. For instance, the pdeA pgpH mutant was defective for the synthesis of peptidoglycan muropeptides and was susceptible to cell wall-targeting antimicrobials. Among different muropeptide precursors, we found that the pdeA pgpH strain was particularly impaired in the synthesis of d-Ala-d-Ala, which is required to complete the pentapeptide stem associated with UDP-N-acetylmuramic acid (MurNAc). This was consistent with an increased sensitivity to d-cycloserine, which inhibits the d-alanine branch of peptidoglycan synthesis. Finally, upon examining d-Ala:d-Ala ligase (Ddl), which catalyzes the conversion of d-Ala to d-Ala-d-Ala, we found that its activity was activated by K+ Based on previous reports that c-di-AMP inhibits K+ uptake, we propose that c-di-AMP accumulation impairs peptidoglycan synthesis, partially through the deprivation of cytoplasmic K+ levels, which are required for cell wall-synthetic enzymes.IMPORTANCE The bacterial second messenger c-di-AMP is produced by a large number of bacteria and conditionally essential to many species. Conversely, c-di-AMP accumulation is also toxic to bacterial physiology and pathogenesis, but its mechanisms are largely undefined. We found that in Listeria monocytogenes, elevated c-di-AMP levels diminished muropeptide synthesis and increased susceptibility to cell wall-targeting antimicrobials. Cell wall defects might be an important mechanism for attenuated virulence in bacteria with high c-di-AMP levels.
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10
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Ayon NJ, Sharma AD, Gutheil WG. LC-MS/MS-Based Separation and Quantification of Marfey's Reagent Derivatized Proteinogenic Amino Acid DL-Stereoisomers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:448-458. [PMID: 30421361 PMCID: PMC6417927 DOI: 10.1007/s13361-018-2093-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/15/2018] [Accepted: 10/15/2018] [Indexed: 05/31/2023]
Abstract
D-Amino acids are important biological molecules. Improved analytical methods for their resolution and quantification remain of keen interest. In this study, we investigated the use of Marfey's reagent (chiral) derivatization coupled with LC-MS/MS-based separation and detection of the resulting diastereomers for quantification of the 19 common L- and D-amino acids and glycine. Standard formic acid (pH 2)-based separations on reverse phase media were unable to separate all 19 amino acid DL pairs. In contrast, a water/acetonitrile/ammonium acetate (pH 6.5) solvent system allowed all 19 amino acid DL pairs to be chromatographically resolved on a 30 min gradient, with negative mode detection at pH 6.5 giving good sensitivity. Derivatization reaction rates between amino acids varied substantially, with overnight derivatization required for some amino acids. Chromatography at pH 6.5 combined with MS/MS quantification in negative mode demonstrated good linearity over a wide concentration range for all 20 amino acids. Matrix effects, assessed with an MRSA extract, were negligible. Marfey's derivatized analytes were stable for 24 h at room temperature. This method was demonstrated by determining the levels of these analytes in mid-log phase MRSA extracts. This approach provides for the chromatographic resolution and MS/MS-based quantification of all 20 common L- and D-amino acids in complex matrices. Graphical Abstract.
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Affiliation(s)
- Navid J Ayon
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA
| | - Amar Deep Sharma
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA
| | - William G Gutheil
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO, 64108, USA.
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11
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Ameryckx A, Thabault L, Pochet L, Leimanis S, Poupaert JH, Wouters J, Joris B, Van Bambeke F, Frédérick R. 1-(2-Hydroxybenzoyl)-thiosemicarbazides are promising antimicrobial agents targeting d-alanine-d-alanine ligase in bacterio. Eur J Med Chem 2018; 159:324-338. [DOI: 10.1016/j.ejmech.2018.09.067] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/09/2018] [Accepted: 09/26/2018] [Indexed: 12/21/2022]
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12
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Antibiotic Effects on Methicillin-Resistant Staphylococcus aureus Cytoplasmic Peptidoglycan Intermediate Levels and Evidence for Potential Metabolite Level Regulatory Loops. Antimicrob Agents Chemother 2017; 61:AAC.02253-16. [PMID: 28320719 DOI: 10.1128/aac.02253-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 03/10/2017] [Indexed: 11/20/2022] Open
Abstract
Cytoplasmic peptidoglycan (PG) precursor levels were determined in methicillin-resistant Staphylococcus aureus (MRSA) after exposure to several cell wall-targeting antibiotics. Three experiments were performed: (i) exposure to 4× MIC levels (acute); (ii) exposure to sub-MIC levels (subacute); (iii) a time course experiment of the effect of vancomycin. In acute exposure experiments, fosfomycin increased UDP-GlcNAc, as expected, and resulted in substantially lower levels of total UDP-linked metabolite accumulation relative to other pathway inhibitors, indicating reduced entry into this pathway. Upstream inhibitors (fosfomycin, d-cycloserine, or d-boroalanine) reduced UDP-MurNAc-pentapeptide levels by more than fourfold. Alanine branch inhibitors (d-cycloserine and d-boroalanine) reduced d-Ala-d-Ala levels only modestly (up to 4-fold) but increased UDP-MurNAc-tripeptide levels up to 3,000-fold. Downstream pathway inhibitors (vancomycin, bacitracin, moenomycin, and oxacillin) increased UDP-MurNAc-pentapeptide levels up to 350-fold and UDP-MurNAc-l-Ala levels up to 80-fold, suggesting reduced MurD activity by downstream inhibitor action. Sub-MIC exposures demonstrated effects even at 1/8× MIC which strongly paralleled acute exposure changes. Time course data demonstrated that UDP-linked intermediate levels respond rapidly to vancomycin exposure, with several intermediates increasing three- to sixfold within minutes. UDP-linked intermediate level changes were also multiphasic, with some increasing, some decreasing, and some increasing and then decreasing. The total (summed) UDP-linked intermediate pool increased by 1,475 μM/min during the first 10 min after vancomycin exposure, providing a revised estimate of flux in this pathway during logarithmic growth. These observations outline the complexity of PG precursor response to antibiotic exposure in MRSA and indicate likely sites of regulation (entry and MurD).
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13
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Zhang D, Liu W, Li L, Zhao HY, Sun HY, Meng MH, Zhang S, Shao ML. Key role of peptidoglycan on acrylamide binding by lactic acid bacteria. Food Sci Biotechnol 2017; 26:271-277. [PMID: 30263538 DOI: 10.1007/s10068-017-0036-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 10/15/2016] [Accepted: 10/24/2016] [Indexed: 12/23/2022] Open
Abstract
The primary purpose of this study was to analyze the ability of four peptidoglycan (PGN) from different lactic acid bacteria to bind acrylamide (AA) and to identify the binding mechanism. In this study, to clarify the possible binding interactions among AA and components of PGN, chemical components, surface structure, amino acids component, and functional groups of peptidoglycans were studied. It was found that PGN from Lactobacillus plantarum 1.0065 had the highest ability to bind AA with 87%. Furthermore, a significant positive relation was found between the carbohydrate content of PGN and percentage of bind AA, and the content of four specific amino acids of PGN and AA binding ability were also positive correlated. Thereinto, alanine of PGN had a significant impact on AA binding among four amino acids. Additionally, the C-O (carboxyl, polysaccharides, and arene), C=O amide, and N-H amines groups of PGN were involved in AA binding.
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Affiliation(s)
- Dan Zhang
- 1College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030 China
| | - Wei Liu
- 2Tongjiang entry-exit inspection and Quarantine Bureau, Tongjiang, Heilongjiang, 156400 China
| | - Liang Li
- 1College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030 China
| | - Hong-Yu Zhao
- 1College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030 China
| | - Hong-Yang Sun
- 1College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030 China
| | - Ming-Han Meng
- 1College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030 China
| | - Sheng Zhang
- 1College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030 China
| | - Mei-Li Shao
- 1College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030 China
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