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1.
Int J Mol Sci ; 25(9)2024 Apr 26.
Article in English | MEDLINE | ID: mdl-38731937

ABSTRACT

Due to the favorable features obtained through the incorporation of fluorine atom(s), fluorinated drugs are a group with emerging pharmaceutical importance. As their commercial availability is still very limited, to expand the range of possible candidates, new fluorinated tryptophan analogs were synthesized. Control of enantiopurity during the synthesis procedure requires that highly efficient enantioseparation methods be available. In this work, the enantioseparation of seven fluorinated tryptophans and tryptophan was studied and compared systematically to (i) develop analytical methods for enantioselective separations and (ii) explore the chromatographic features of the fluorotrytophans. For enantioresolution, macrocyclic glycopeptide-based selectors linked to core-shell particles were utilized, applying liquid chromatography-based methods. Application of the polar-ionic mode resulted in asymmetric and broadened peaks, while reversed-phase conditions, together with mobile-phase additives, resulted in baseline separation for all studied fluorinated tryptophans. The marked differences observed between the methanol and acetonitrile-containing eluent systems can be explained by the different solvation abilities of the bulk solvents of the applied mobile phases. Among the studied chiral selectors, teicoplanin and teicoplanin aglycone were found to work effectively. Under optimized conditions, baseline separations were achieved within 6 min. Ionic interactions were semi-quantitatively characterized and found to not influence enantiorecognition. Interestingly, fluorination of the analytes does not lead to marked changes in the chromatographic characteristics of the methanol-containing eluents, while larger differences were noticed when the polar but aprotic acetonitrile was applied. Experiments conducted on the influence of the separation temperature indicated that the separations are enthalpically driven, with only one exception. Enantiomeric elution order was found to be constant on both teicoplanin and teicoplanin aglycone-based chiral stationary phases (L < D) under all applied chromatographic conditions.


Subject(s)
Glycopeptides , Halogenation , Teicoplanin , Tryptophan , Tryptophan/chemistry , Tryptophan/analogs & derivatives , Glycopeptides/chemistry , Stereoisomerism , Teicoplanin/chemistry , Teicoplanin/analogs & derivatives , Chromatography, Liquid/methods , Chromatography, High Pressure Liquid/methods , Macrocyclic Compounds/chemistry
2.
Molecules ; 28(3)2023 Jan 26.
Article in English | MEDLINE | ID: mdl-36770866

ABSTRACT

The enantioselective potential of two macrocyclic glycopeptide-based chiral stationary phases for analysis of 28 structurally diverse biologically active compounds such as derivatives of pyrovalerone, ketamine, cathinone, and other representatives of psychostimulants and antidepressants was evaluated in sub/supercritical fluid chromatography. The chiral selectors immobilized on 2.7 µm superficially porous particles were teicoplanin (TeicoShell column) and modified macrocyclic glycopeptide (NicoShell column). The influence of the organic modifier and different mobile phase additives on the retention and enantioresolution were investigated. The obtained results confirmed that the mobile phase additives, especially water as a single additive or in combination with basic and acidic additives, improve peak shape and enhance enantioresolution. In addition, the effect of temperature was evaluated to optimize the enantioseparation process. Both columns exhibited comparable enantioselectivity, approximately 90% of the compounds tested were enantioseparated, and 30% out of them were baseline enantioresolved under the tested conditions. The complementary enantioselectivity of the macrocyclic glycopeptide-based chiral stationary phases was emphasized. This work can be useful for the method development for the enantioseparation of basic biologically active compounds of interest.


Subject(s)
Chromatography, Supercritical Fluid , Chromatography, Supercritical Fluid/methods , Stereoisomerism , Glycopeptides/chemistry , Teicoplanin/chemistry , Pharmaceutical Preparations
3.
Chem Res Toxicol ; 35(2): 199-202, 2022 02 21.
Article in English | MEDLINE | ID: mdl-35107993

ABSTRACT

Teicoplanin is a glycopeptide antibiotic deployed to combat Gram-positive bacterial infection and has recently been associated with development of adverse drug reactions, particularly following previous exposure to vancomycin. In this study, we generated teicoplanin-specific monoclonal T-cell populations from healthy volunteers expressing HLA-A*32:01 and defined pathways of T-cell activation and HLA allele restriction. Teicoplanin-responsive T-cells were CD8+, HLA class I-restricted, and cross-reacted with the lipoglycopeptide daptomycin in proliferation and cytokine/cytolytic molecule (granzyme B, Perforin, and FasL) release assays. These data show that teicoplanin activates T-cells, which may play a role in the pathogenesis of teicoplanin-induced adverse events, in HLA-A*32:01 positive donors.


Subject(s)
Anti-Bacterial Agents/pharmacology , HLA-A Antigens/biosynthesis , T-Lymphocytes/drug effects , Teicoplanin/pharmacology , Anti-Bacterial Agents/chemistry , Healthy Volunteers , Humans , T-Lymphocytes/metabolism , Teicoplanin/chemistry
4.
Chirality ; 34(12): 1494-1502, 2022 12.
Article in English | MEDLINE | ID: mdl-36221174

ABSTRACT

Chiral carbon nanoparticles (CNPs) represent a rapidly evolving area of research for optical and biomedical technologies. Similar to small molecules, applications of CNPs as well as fundamental relationships between their optical activity and structural asymmetry would greatly benefit from their enantioselective separations by chromatography. However, this technique remains in its infancy for chiral carbon and other nanoparticles. The possibility of effective separations using high performance liquid chromatography (HPLC) with chiral stationary phases remains an open question whose answer can also shed light on the components of multiscale chirality of the nanoparticles. Herein, we report a detailed methodology of HPLC for successful separation of chiral CNPs and establish a path for its future optimization. A mobile phase of water/acetonitrile was able to achieve chiral separation of CNPs derived from L- and D-cysteine denoted as L-CNPs and D-CNPs. Molecular dynamics simulations show that the teicoplanin-based stationary phase has a higher affinity for L-CNPs than for D-CNPs, in agreement with experiments. The experimental and computational findings jointly indicate that chiral centers of chiral CNPs are present at their surface, which is essential for the multiple applications of these chiral nanostructures and equally essential for interactions with biomolecules and circularly polarized photons.


Subject(s)
Nanoparticles , Teicoplanin , Stereoisomerism , Teicoplanin/chemistry , Chromatography, High Pressure Liquid/methods , Carbon/chemistry , Nanoparticles/chemistry
5.
J Microencapsul ; 39(3): 288-297, 2022 May.
Article in English | MEDLINE | ID: mdl-35475397

ABSTRACT

The aim of our work is to formulate teicoplanin-loaded lipid liquid-crystalline (cubosomes) nanoparticles laden gel to sustain the release of teicoplanin for effective treatment of infected bone. Cubosomal gels were prepared by emulsification technique. The batches were characterised for morphology, size, entrapment efficacy, viscosity, in-vitro flux, in-vivo drug release and histopathological studies. Transmission electron microscopy images confirmed the bi-continuous liquid crystalline phase. The size (61-202 nm), viscosity (12 138-13 132 cp), and entrapment efficacy (69.0-81.8% w/w) increase with the level of glycerol monooleate. The in-vitro flux data showed sustain teicoplanin release from the cubosomal gels for 36 days, compared to 48 h from the control gel. The in-vivo teicoplanin release study (osteomyelitis induced by S. aureus) showed low serum drug-concentration from the gel (up to 14 days) compared to high-serum drug-concentration using intravenous injections. In conclusion the study demonstrated the potential of cubosomes for effective delivery of teicoplanin to replace injections.


Subject(s)
Nanoparticles , Osteomyelitis , Gels/chemistry , Humans , Nanoparticles/chemistry , Osteomyelitis/drug therapy , Osteomyelitis/pathology , Particle Size , Staphylococcus aureus , Teicoplanin/chemistry , Teicoplanin/therapeutic use
6.
Nanotechnology ; 32(46)2021 Aug 27.
Article in English | MEDLINE | ID: mdl-34330111

ABSTRACT

The use of nanoparticles is one of the strategies currently studied to minimize the toxicity and lack of tissue specificity of many cancer drugs used in chemotherapy. In this research the physicochemical and biological behavior of a novel self-assembled nanostructure of the antibiotic Teicoplanin (Teico) was characterized as a nanocarrier system for solubilizing highly hydrophobic drugs like Paclitaxel (Ptx) in aqueous media. The Teico micelles were loaded with Ptx in DMSO or PEG-400. The interaction between the loaded micelles and Albumin human serum albumin (HSA) was then studied by size exclusion chromatography. Transmission electron microscopy, dynamic light scattering and high-resolution liquid chromatography were also used to characterize the physicochemical and structural properties of the micelles to form the Teico/Ptx and Teico/Ptx/HSA micelles. Cellular uptake of Ptx was evaluated by fluorescent microscopy. Thein vitrocytotoxicity of the complexes was studied on Hep-2 tumor cells, by a Crystal Violet assay. Teico cosolvent-free micelles can solubilize up to 20 mg.ml-1of Ptx dissolved in PEG, increasing four times the solubility of Ptx in water compared to Abraxane, and 20 000 times the intrinsic solubility of Ptx in water. In addition, Teico/Ptx micelles binds spontaneously HSA through hydrophobic interaction. Teico and Teico/HSA micelles as a Ptx transporter does not affect its release or biological activity. Therefore, Teico/Ptx or Teico/Ptx/HSA complexes appear as new alternatives for transporting larger amounts of hydrophobic drugs that offer advantages, turning it an interesting option for further study.


Subject(s)
Bridged-Ring Compounds/chemistry , Drug Carriers/chemistry , Glycopeptides/chemistry , Nanoparticles/chemistry , Taxoids/chemistry , Teicoplanin/chemistry , Antineoplastic Agents/chemistry , Cell Line, Tumor , Humans , Micelles , Paclitaxel/chemistry , Particle Size , Polyethylene Glycols/chemistry , Solubility
7.
Nature ; 521(7550): 105-9, 2015 May 07.
Article in English | MEDLINE | ID: mdl-25686610

ABSTRACT

Non-ribosomal peptide synthetase (NRPS) mega-enzyme complexes are modular assembly lines that are involved in the biosynthesis of numerous peptide metabolites independently of the ribosome. The multiple interactions between catalytic domains within the NRPS machinery are further complemented by additional interactions with external enzymes, particularly focused on the final peptide maturation process. An important class of NRPS metabolites that require extensive external modification of the NRPS-bound peptide are the glycopeptide antibiotics (GPAs), which include vancomycin and teicoplanin. These clinically relevant peptide antibiotics undergo cytochrome P450-catalysed oxidative crosslinking of aromatic side chains to achieve their final, active conformation. However, the mechanism underlying the recruitment of the cytochrome P450 oxygenases to the NRPS-bound peptide was previously unknown. Here we show, through in vitro studies, that the X-domain, a conserved domain of unknown function present in the final module of all GPA NRPS machineries, is responsible for the recruitment of oxygenases to the NRPS-bound peptide to perform the essential side-chain crosslinking. X-ray crystallography shows that the X-domain is structurally related to condensation domains, but that its amino acid substitutions render it catalytically inactive. We found that the X-domain recruits cytochrome P450 oxygenases to the NRPS and determined the interface by solving the structure of a P450-X-domain complex. Additionally, we demonstrated that the modification of peptide precursors by oxygenases in vitro--in particular the installation of the second crosslink in GPA biosynthesis--occurs only in the presence of the X-domain. Our results indicate that the presentation of peptidyl carrier protein (PCP)-bound substrates for oxidation in GPA biosynthesis requires the presence of the NRPS X-domain to ensure conversion of the precursor peptide into a mature aglycone, and that the carrier protein domain alone is not always sufficient to generate a competent substrate for external cytochrome P450 oxygenases.


Subject(s)
Cytochrome P-450 Enzyme System/metabolism , Glycopeptides/biosynthesis , Peptide Synthases/chemistry , Peptide Synthases/metabolism , Amino Acid Sequence , Crystallography, X-Ray , Models, Molecular , Protein Structure, Tertiary , Teicoplanin/analogs & derivatives , Teicoplanin/biosynthesis , Teicoplanin/chemistry , Teicoplanin/metabolism , Vancomycin/biosynthesis
8.
Anal Chem ; 92(16): 11462-11468, 2020 08 18.
Article in English | MEDLINE | ID: mdl-32693581

ABSTRACT

The intracellular invasion and survival of a pathogen like Staphylococcus aureus (S. aureus) within host cells enable them to resist antibiotic treatment and colonize long-term in the host, which leads to a series of clinical issues. Rapid and specific detection of intracellular bacteria is important in diagnosis of infection and guiding antibiotic administration. Herein, this work reports a simple one-step fluorescence resonance energy transfer (FRET) platform-based strategy to achieve specific and rapid detection of S. aureus in specimens of phagocytic cells. The aptamer modified quantum dots (Aptamer-QDs) and antibiotic molecule of Teicoplanin functionalized-gold nanoparticles (Teico-AuNPs) dual-recognition units to S. aureus are employed as energy donor and acceptor, respectively. Based on the "off" to "on" signal readout mode, when in the presence of target S. aureus, the donor and acceptor are close to each other and bring high FRET efficiency, which is suitable for analysis of intracellular S. aureus. After it was incubated with the sample for 2 h, the as-prepared FRET sensor showed selectivity to the target S. aureus, and the changed fluorescence signal shows an obvious variation with increasing concentration of S. aureus in pure buffer. When the FRET strategy was further applied to assay intracellular S. aureus, there was an obvious fluorescence signal change obtained both by spectrum analysis and visual fluorescence microscope observation when the average number of S. aureus in one host cell (NS. aureus/cell) was as low as 1, which can be attributed to the high fluorescence quenching efficiency of about 41.3%. It could be envisioned that this FRET nanoprobe with high fluorescence quenching efficiency may provide a simple approach for the facile, selective, and rapid diagnosis of an intracellular bacterial infection.


Subject(s)
Aptamers, Nucleotide/chemistry , Bacterial Load/methods , Fluorescence Resonance Energy Transfer/methods , Fluorescent Dyes/chemistry , Quantum Dots/chemistry , Staphylococcus aureus/isolation & purification , Animals , Gold/chemistry , Limit of Detection , Macrophages/microbiology , Metal Nanoparticles/chemistry , Mice , RAW 264.7 Cells , Staphylococcus aureus/chemistry , Teicoplanin/chemistry
9.
Analyst ; 145(13): 4436-4441, 2020 Jul 07.
Article in English | MEDLINE | ID: mdl-32469359

ABSTRACT

Anti-Stokes fluorescence induced by near-IR (NIR) radiation is particularly advantageous for the bioassay of complex samples, but most of the commonly used NIR-induced fluorescence nanomaterials such as up-conversion nanoparticles (UCNPs) do not exhibit satisfactory fluorescence intensity and work against achieving a highly sensitive bioassay. In this study, we a construct sensitive and specific bacteria biosensor based on the NIR-stimulated CaS: Eu, Sm, Mn and SrS: Ce, Sm, Mn nanoparticles. The fluorescent nanoparticles are conjugated with bacteria recognition fragments. In addition, the independent emission bands of these two types of fluorescent nanoparticles make it possible to detect and quantify Gram-positive strain and Gram-negative strain, simultaneously. Intense fluorescence and magnetic enrichment of magneto-fluorescence systems enable bacteria discrimination with the naked eye and improve sensitivity in trace bacteria detection (<20 CFU mL-1). The linear relationship between the fluorescence intensity and bacterial concentration is established with a detection range of 25-106 CFU mL-1. Furthermore, this NIR-excited assay strategy demonstrates better anti-interference capability than UV/visible-excited assay methods, showing high potential and practical value for medical diagnostics and bacteria monitoring.


Subject(s)
Bacteriological Techniques/methods , Escherichia coli/isolation & purification , Fluorescent Dyes/chemistry , Metal Nanoparticles/chemistry , Staphylococcus aureus/isolation & purification , Animals , Calcium Compounds/chemistry , Calcium Compounds/radiation effects , Escherichia coli/chemistry , Fluorescence , Food Contamination/analysis , Infrared Rays , Limit of Detection , Magnetic Phenomena , Metal Nanoparticles/radiation effects , Metals, Heavy/chemistry , Metals, Heavy/radiation effects , Microscopy, Fluorescence , Milk/microbiology , Polymyxin B/chemistry , Spectrometry, Fluorescence , Staphylococcus aureus/chemistry , Sulfides/chemistry , Sulfides/radiation effects , Teicoplanin/chemistry
10.
Appl Microbiol Biotechnol ; 104(8): 3279-3291, 2020 Apr.
Article in English | MEDLINE | ID: mdl-32076781

ABSTRACT

Teicoplanin (Tcp) is a clinically relevant glycopeptide antibiotic (GPA) that is produced by the actinobacterium Actinoplanes teichomyceticus. Tcp is a front-line therapy for treating severe infections caused by multidrug-resistant Gram-positive pathogens in adults and infants. In this review, we provide a detailed overview of how Tcp is produced by A. teichomyceticus by describing Tcp biosynthesis, regulation, and resistance. We summarize the knowledge gained from in vivo and in vitro studies to provide an integrated model of teicoplanin biosynthesis. Then, we discuss genetic and nutritional factors that contribute to the regulation of teicoplanin biosynthesis, focusing on those that have been successfully applied for improving teicoplanin production. A current view on teicoplanin self-resistance mechanisms in A. teichomyceticus is given, and we compare the Tcp biosynthetic gene cluster with other glycopeptide gene clusters from actinoplanetes and from unidentified isolates/metagenomics samples. Finally, we provide an outlook for further directions in studying Tcp biosynthesis and regulation.


Subject(s)
Actinoplanes/genetics , Actinoplanes/metabolism , Anti-Bacterial Agents/biosynthesis , Gene Expression Regulation, Bacterial , Multigene Family , Teicoplanin/biosynthesis , Anti-Bacterial Agents/chemistry , Bacteria/drug effects , Biosynthetic Pathways , Teicoplanin/chemistry
11.
Molecules ; 25(18)2020 Sep 08.
Article in English | MEDLINE | ID: mdl-32911715

ABSTRACT

Dalbavancin is a novel semisynthetic glycopeptide antibiotic that comprises multiple homologs and isomers of similar polarities. However, pharmacokinetic studies have only analyzed the primary components of dalbavancin, namely B0 and B1. In this study, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously determinate and investigate the five homologous components of dalbavancin, namely, A0, A1, B0, B1, and B2, in rat plasma. In this method, methanol was used to precipitate plasma, and a triple-bonded alkyl chromatographic column was used for molecule separation, using 0.1% formic acid-acetonitrile as the mobile phase for gradient elution. Targeted homologs were analyzed by a triple quadrupole mass spectrometer using positive electrospray ionization in multiple reaction monitoring mode. The linearity range was 50-2500 ng/mL with a high correlation coefficient (r2 > 0.998). This method was successfully applied in the pharmacokinetic analysis of dalbavancin hydrochloride to investigate dalbavancin components in rats.


Subject(s)
Chromatography, High Pressure Liquid , Tandem Mass Spectrometry , Teicoplanin/analogs & derivatives , Animals , Drug Monitoring , Molecular Structure , Rats , Reproducibility of Results , Sensitivity and Specificity , Teicoplanin/chemistry , Teicoplanin/pharmacokinetics
12.
World J Microbiol Biotechnol ; 36(5): 69, 2020 Apr 25.
Article in English | MEDLINE | ID: mdl-32333113

ABSTRACT

Emergence of resistance to traditional antibiotic treatments necessitates alternative delivery systems. Teicoplanin is a glycopeptide antibiotic used in the treatments of serious infections caused by Gram-positive bacteria, including Methicillin Resistant Staphylococcus aureus (MRSA). One strategy to keep up with antibiotic resistance development is to limit dose and amount during treatments. Targeted delivery systems of antibiotics have been suggested as a mechanism to slow-down the evolution of resistance and to increase efficiency of the antimicrobials on already resistant pathogens. In this study, we report teicoplanin delivery nanoparticles of Poly Lactic-co-Glycolic Acid (PLGA), which are functionalized with S. aureus specific aptamers. A 32-fold decrease in minimum inhibitory concentration (MIC) values of teicoplanin for S. aureus was demonstrated for susceptible strains and about 64-fold decline in MIC value was achieved for moderately resistant clinical isolates of MRSA upon teicoplanin treatment with aptamer-PLGA nanoparticles. Although teicoplanin delivery in PLGA nanoparticles without targeting demonstrated eightfold decrease in MIC of susceptible strains of S. aureus and S. epidermidis and twofold in MIC of resistant strains, the aptamer targeting specifically decreased MIC for S. aureus, but not for S. epidermidis. Therefore, aptamer-targeted PLGA delivery of antibiotic can be an attractive alternative to combat with some of the multi-drug resistant bacterial pathogens.


Subject(s)
Anti-Bacterial Agents/pharmacology , Nanoparticles/chemistry , Polylactic Acid-Polyglycolic Acid Copolymer/pharmacology , Staphylococcus aureus/drug effects , Teicoplanin/pharmacology , Anti-Bacterial Agents/chemistry , Drug Resistance, Multiple, Bacterial , Methicillin-Resistant Staphylococcus aureus/drug effects , Microbial Sensitivity Tests , Nanoparticles/administration & dosage , Polylactic Acid-Polyglycolic Acid Copolymer/chemistry , Staphylococcal Infections/drug therapy , Staphylococcal Infections/microbiology , Staphylococcus aureus/growth & development , Staphylococcus epidermidis/drug effects , Teicoplanin/chemistry
13.
Article in English | MEDLINE | ID: mdl-30397070

ABSTRACT

The determination of antibiotic potency against bacterial strains by assessment of their minimum inhibitory concentration normally uses a standardized broth microdilution assay procedure developed more than 50 years ago. However, certain antibiotics require modified assay conditions in order to observe optimal activity. For example, daptomycin requires medium supplemented with Ca2+, and the lipoglycopeptides dalbavancin and oritavancin require Tween 80 to be added to the growth medium to prevent the depletion of free drug via adsorption to the plastic microplate. In this report, we examine systematically the effects of several different plate types on microdilution broth MIC values for a set of antibiotics against Gram-positive and Gram-negative bacteria, both in medium alone and in medium supplemented with the commonly used additives Tween 80, lysed horse blood, and 50% human serum. We observed very significant differences in measured MICs (up to 100-fold) for some lipophilic antibiotics, such as the Gram-positive lipoglycopeptide dalbavancin and the Gram-negative lipopeptide polymyxins, and found that nonspecific binding plates can replace the need for surfactant additives. Microtiter plate types and any additives should be specified when reporting broth dilution MIC values, as results can vary dramatically for some classes of antibiotics.


Subject(s)
Culture Media/chemistry , Escherichia coli/drug effects , Methicillin-Resistant Staphylococcus aureus/drug effects , Microbial Sensitivity Tests/instrumentation , Aminoglycosides/chemistry , Aminoglycosides/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Calcium/pharmacology , Ciprofloxacin/chemistry , Ciprofloxacin/pharmacology , Colistin/chemistry , Colistin/pharmacology , Culture Media/pharmacology , Depsipeptides/chemistry , Depsipeptides/pharmacology , Escherichia coli/growth & development , Escherichia coli/metabolism , Factor Analysis, Statistical , Lipoglycopeptides/chemistry , Lipoglycopeptides/pharmacology , Methicillin-Resistant Staphylococcus aureus/growth & development , Methicillin-Resistant Staphylococcus aureus/metabolism , Oxacillin/chemistry , Oxacillin/pharmacology , Penicillin G/chemistry , Penicillin G/pharmacology , Plastics/chemistry , Polymyxin B/chemistry , Polymyxin B/pharmacology , Polysorbates/pharmacology , Rifampin/chemistry , Rifampin/pharmacology , Teicoplanin/analogs & derivatives , Teicoplanin/chemistry , Teicoplanin/pharmacology , Trimethoprim/chemistry , Trimethoprim/pharmacology , Vancomycin/chemistry , Vancomycin/pharmacology
14.
Electrophoresis ; 40(15): 1966-1971, 2019 08.
Article in English | MEDLINE | ID: mdl-30725477

ABSTRACT

This work deals with the potentiality of nano liquid chromatography (Nano-LC) for the chiral separation of racemic mixture of tryptophan and some selected derivatives by using 100 µm i.d. fused silica capillary packed with teicoplanin bonded to 5 µm diol silica stationary phase. The experiments were carried out by using a cheap and laboratory-assembled nano-LC-UV system. Elution was done in an isocratic mode using a polar organic mobile phase. In order to find the optimum chiral separation of the studied enantiomers, some chromatographic experimental parameters were systematically studied and optimized. Among them, mobile phase composition, namely organic modifier type and concentration, buffer type and pH and aqueous content and sample solvent dilution on retention time, retention factor and enantioresolution factor were studied. Baseline enantioresolution and good peak shape was achieved utilizing the mobile phase containing 40 mM ammonium formate at pH pH 2.5 in ACN/water/acetone (60:30:10, v/v/v) at 520 nL/min in less than 8 min analysis time.


Subject(s)
Chromatography, Liquid/methods , Nanotechnology/methods , Silicon Dioxide/chemistry , Teicoplanin/chemistry , Tryptophan , Stereoisomerism , Tryptophan/analogs & derivatives , Tryptophan/analysis , Tryptophan/chemistry , Tryptophan/isolation & purification
15.
Article in English | MEDLINE | ID: mdl-30275088

ABSTRACT

Glycopeptide antibiotics (GPAs) include clinically important drugs used for the treatment of infections caused by Gram-positive pathogens. These antibiotics are specialized metabolites produced by several genera of actinomycete bacteria. While many GPAs are highly chemically modified, A47934 is a relatively unadorned GPA lacking sugar or acyl modifications, common to other members of the class, but which is chlorinated at three distinct sites. The biosynthesis of A47934 is encoded by a 68-kb gene cluster in Streptomyces toyocaensis NRRL 15009. The cluster includes all necessary genes for the synthesis of A47934, including two predicted halogenase genes, staI and staK In this study, we report that only one of the halogenase genes, staI, is necessary and essential for A47934 biosynthesis. Chlorination of the A47934 scaffold is important for antibiotic activity, as assessed by binding affinity for the target N-acyl-d-Ala-d-Ala. Surprisingly, chlorination is also vital to avoid activation of enterococcal and Streptomyces VanB-type GPA resistance through induction of resistance genes. Phenotypic assays showed stronger induction of GPA resistance by the dechlorinated compared to the chlorinated GPA. Correspondingly, the relative expression of the enterococcal vanA resistance gene was shown to be increased by the dechlorinated compared to the chlorinated compound. These results provide insight into the biosynthesis of GPAs and the biological function of GPA chlorination for this medically important class of antibiotic.


Subject(s)
Bacterial Proteins/metabolism , Glycopeptides/chemistry , Ristocetin/analogs & derivatives , Streptomyces/drug effects , Bacterial Proteins/genetics , Drug Resistance, Bacterial , Enterococcus faecalis/drug effects , Gene Deletion , Glycopeptides/pharmacology , Halogenation , Microbial Sensitivity Tests , Molecular Structure , Multigene Family , Ristocetin/biosynthesis , Ristocetin/chemistry , Ristocetin/pharmacology , Streptomyces/genetics , Streptomyces/metabolism , Teicoplanin/chemistry , Teicoplanin/pharmacology
16.
Chirality ; 30(12): 1304-1311, 2018 12.
Article in English | MEDLINE | ID: mdl-30321474

ABSTRACT

New chiral high-performance liquid chromatography (HPLC) method for the enantiomeric resolution of quinolones is developed and described. The column used was Chirobiotic T (150 × 4.6 mm, 5.0 µm). Three mobile phases used were MeOH:ACN:Water:TEA (70:10:20:0.1%), (60:30:10:0.1%), and (50:30:20:0.1%). The flow rate of the mobile phases was 1.0 mL/min with UV detection at different wavelengths. The values of retention, resolution, and separation factors ranged from 1.5 to 6.0, 1.80 to 2.25, and 2.86 to 6.0, respectively. The limit of detection and quantification ranged from 4.0 to 12 ng and 40 to 52 ng, respectively. The modeling studies indicated strong interactions of R-enantiomers with teicoplanin chiral selector than S-enantiomers. The supra molecular mechanism of the chiral recognition was established by modeling and chromatographic studies. It was observed that hydrogen bondings and π-π interactions are the major forces for chiral separation. The present chiral HPLC method may be used for enantiomeric resolution of quinolones in any matrices.


Subject(s)
Chromatography, High Pressure Liquid/methods , Quinolones/chemistry , Quinolones/isolation & purification , Teicoplanin/chemistry , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Glycopeptides/chemistry , Hydrogen Bonding , Limit of Detection , Macrocyclic Compounds/chemistry , Models, Chemical , Molecular Docking Simulation , Reproducibility of Results , Stereoisomerism
17.
J Sep Sci ; 41(6): 1240-1246, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29230946

ABSTRACT

Carnosine is present in high concentrations in specific human tissues such as the skeletal muscle, and among its biological functions, the remarkable scavenging activity toward reactive carbonyl species is noteworthy. Although the two enantiomers show almost identical scavenging reactivity toward reactive carbonyl species, only d-carnosine is poorly adsorbed at the gastrointestinal level and is stable in human plasma. Direct methods for the enantioselective analysis of carnosine are still missing even though they could find more effective applications in the analysis of complex matrices. In the present study, the use of two different chiral stationary phases is presented. A chiral ligand-exchange chromatography stationary phase based on N,S-dioctyl-d-penicillamine resulted in the direct enantioseparation of carnosine. Indeed, running the analysis at 25°C and 1.0 mL/min with a 1.5 mM copper(II) sulfate concentration allowed us to obtain separation and resolution factors of 3.37 and 12.34, respectively. However, the use of a copper(II)-containing eluent renders it hardly compatible with mass spectrometry detectors. With the teicoplanin-based stationary phase, a mass spectrometry compatible method was successfully developed. Indeed, a water/methanol 60:40 v/v pH 3.1 eluent flowed at 1.0 mL/min and with a 25°C column temperature produced separation and resolution factors of 2.60 and 4.16, respectively.


Subject(s)
Carnosine/isolation & purification , Penicillamine/chemistry , Teicoplanin/chemistry , Carnosine/chemistry , Chromatography, High Pressure Liquid , Molecular Structure , Stereoisomerism
18.
Biochemistry (Mosc) ; 83(10): 1222-1230, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30472959

ABSTRACT

As key regulators of cell signaling, protein kinases (PKs) are attractive targets for therapeutic intervention in a variety of diseases. Herein, we report for the first time the inhibitory activity of polycyclic peptides, particularly, derivatives of glycopeptide antibiotics teicoplanin and eremomycin, against a panel of 12 recombinant human protein kinases and two protein kinases (CK1 and CK2) isolated from rat liver. Several of the investigated compounds inhibited various PKs with IC50 values below 10 µM and caused >90% suppression of the enzyme activity at 10 µM concentration. Kinetic analysis of the protein kinase CK2α inhibition by the teicoplanin aglycon analogue (7) demonstrated the non-competitive mechanism of inhibition (with regard to ATP). Interestingly, the inhibitory activity of some investigated compounds correlated with the earlier described antiviral activity against HIV, HCV, and other corona- and flaviviruses.


Subject(s)
Anti-Bacterial Agents/chemistry , Glycopeptides/chemistry , Protein Kinase Inhibitors/metabolism , Protein Kinases/metabolism , Animals , Antiviral Agents/chemistry , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , HIV/physiology , Humans , Hydrophobic and Hydrophilic Interactions , Inhibitory Concentration 50 , Kinetics , Liver/metabolism , Protein Kinase Inhibitors/chemistry , Protein Kinases/chemistry , Protein Kinases/genetics , Rats , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Teicoplanin/chemistry , Virus Replication/drug effects
19.
Mikrochim Acta ; 185(8): 391, 2018 07 28.
Article in English | MEDLINE | ID: mdl-30056493

ABSTRACT

An affinity-based protocol is described for the detection of Staphylococcus aureus (S. aureus). It is utilizing teicoplanin-functionalized magnetic beads as carriers. Teicoplanin, which binds to the walls of cells of S. aureus via five hydrogen bonds, acts as the recognition agent. Captured S. aureus is magnetically separated from the sample matrix and then specifically lysed by lysostaphin which cleaves the cross-linking pentaglycine bridges of peptidoglycan in the cell wall. Lastly, S. aureus is quantified via the inhibitory effect of released intracellular catalase on a chemiluminescent (CL) system composed of peroxidase, luminol, H2O2 and p-iodophenol because catalase decomposes H2O2. S. aureus can be detected with CL response in the 140 to 1.4 × 107 CFU·mL-1 concentration range and a detection limit as low as 47 CFU·mL-1 at a signal-to-noise ratio of 3. The method was evaluated by analyzing spiked samples including milk, human urine and saline injection solutions. The reliability was demonstrated by a recovery test and by comparison with a conventional plate counting method. Graphical abstract An antibiotic-affinity protocol is developed to detect Staphylococcus aureus (S. aureus) by utilizing teicoplanin-functionalized magnetic beads (Teic-MBs) as carriers. S. aureus can be quantified by measuring the inhibition of luminol chemiluminescence (CL) signal by intracellular catalase.


Subject(s)
Biosensing Techniques/methods , Catalase/metabolism , Intracellular Space/enzymology , Luminol/chemistry , Microspheres , Staphylococcus aureus/isolation & purification , Teicoplanin/chemistry , Animals , Biocatalysis , Horseradish Peroxidase/metabolism , Hydrogen Peroxide/metabolism , Iodobenzenes/metabolism , Limit of Detection , Luminescence , Magnets/chemistry , Milk/microbiology
20.
Electrophoresis ; 38(9-10): 1374-1382, 2017 05.
Article in English | MEDLINE | ID: mdl-28251666

ABSTRACT

A facile, mild method for the preparation of teicoplanin (TE) modified Fe3 O4 microparticles (MPs) employing polydopamine (PDA) layer as a versatile secondary reaction platform was developed. The synthesized magnetic MPs (Fe3 O4 @PDA@TE) were characterized by various characterization techniques, such as TEM, zeta potential etc, to affirm the successful modification of TE to magnetic Fe3 O4 MPs. Using the as-synthesized materials as chiral adsorbents, efficient chiral separation of representative racemic compounds was successfully achieved. Due to the magnetic responsivity, the materials were easily isolated from the racemic solutions under an external magnetic field and could be readily reused for at least three times. Thus, the well-prepared functional magnetic MPs have great potential in preparative chiral separation.


Subject(s)
Electrophoresis, Capillary/methods , Ferrosoferric Oxide/chemistry , Indoles/chemistry , Microspheres , Polymers/chemistry , Teicoplanin/chemistry , Adsorption , Stereoisomerism
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