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1.
Toxins (Basel) ; 15(2)2023 02 06.
Article in English | MEDLINE | ID: mdl-36828446

ABSTRACT

N-glycolylneuraminic acid (Neu5Gc) is a specific factor in red meat that induces intestinal disease. Our aim was to investigate the effect of Neu5Gc on the intestinal barrier as well as its mechanism of endocytosis and exocytosis. Ten specific inhibitors were used to explore the mechanism of Neu5Gc endocytosis and exocytosis by Caco-2 cells. Amiloride hydrochloride and cytochalasin D had the strongest inhibitory effect on the endocytosis of Neu5Gc. Sodium azide, dynasore, chlorpromazine hydrochloride, and nystatin also inhibited Neu5Gc endocytosis. Dynasore exhibited a stronger inhibitory effect than that of chlorpromazine hydrochloride or nystatin alone. Exocytosis inhibitors, including nocodazole, brefeldin A, monensin, and bafilomycin A, inhibited the transmembrane transport of Neu5Gc. Monensin promoted the exocytosis of Neu5Gc from Caco-2 cells. In another experiment, we observed no significant inhibitory effects of monensin and brefeldin A. Dietary concentrations of Neu5Gc induced prominent damage to intestinal tight junction proteins zonula occludens-1 (ZO-1), occludin, and claudin-1 and promoted the phosphorylation of IκB-α and P65 to activate the canonical Nuclear Factor kappa-B (NF-κB) pathway. Neu5Gc increased the RNA levels of pro-inflammatory factors IL-1ß, IL-6, and TNF-α and inhibited those of anti-inflammatory factors TGF-ß and IL-10. BAY, an NF-κB signaling pathway inhibitor, attenuated these changes. Reductions in the levels of ZO-1, occludin, and claudin-1 were recovered in response to BAY. Our data reveal the endocytosis and exocytosis mechanism of Neu5Gc and prove that Neu5Gc can activate the canonical NF-κB signaling pathway, regulate the transcription of inflammatory factors, thereby damaging intestinal barrier function.


Subject(s)
Chlorpromazine , NF-kappa B , Humans , NF-kappa B/metabolism , Caco-2 Cells , Occludin , Claudin-1/metabolism , Brefeldin A/metabolism , Brefeldin A/pharmacology , Chlorpromazine/metabolism , Chlorpromazine/pharmacology , Monensin/metabolism , Monensin/pharmacology , Nystatin/metabolism , Nystatin/pharmacology , Signal Transduction , Intestinal Mucosa
2.
Front Cell Infect Microbiol ; 13: 1122340, 2023.
Article in English | MEDLINE | ID: mdl-36798083

ABSTRACT

Background: The increasing prevalence of invasive fungal infections in immuno-compromised patients is a considerable cause of morbidity and mortality. With the rapid emergence of antifungal resistance and an inadequate pipeline of new therapies, novel treatment strategies are now urgently required. Methods: The antifungal activity of the alginate oligosaccharide OligoG in conjunction with nystatin was tested against a range of Candida spp. (C. albicans, C. glabrata, C. parapsilosis, C. auris, C. tropicalis and C. dubliniensis), in both planktonic and biofilm assays, to determine its potential clinical utility to enhance the treatment of candidal infections. The effect of OligoG (0-6%) ± nystatin on Candida spp. was examined in minimum inhibitory concentration (MIC) and growth curve assays. Antifungal effects of OligoG and nystatin treatment on biofilm formation and disruption were characterized using confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and ATP cellular viability assays. Effects on the cell membrane were determined using permeability assays and transmission electron microscopy (TEM). Results: MIC and growth curve assays demonstrated the synergistic effects of OligoG (0-6%) with nystatin, resulting in an up to 32-fold reduction in MIC, and a significant reduction in the growth of C. parapsilosis and C. auris (minimum significant difference = 0.2 and 0.12 respectively). CLSM and SEM imaging demonstrated that the combination treatment of OligoG (4%) with nystatin (1 µg/ml) resulted in significant inhibition of candidal biofilm formation on glass and clinical grade silicone surfaces (p < 0.001), with increased cell death (p < 0.0001). The ATP biofilm disruption assay demonstrated a significant reduction in cell viability with OligoG (4%) alone and the combined OligoG/nystatin (MIC value) treatment (p < 0.04) for all Candida strains tested. TEM studies revealed the combined OligoG/nystatin treatment induced structural reorganization of the Candida cell membrane, with increased permeability when compared to the untreated control (p < 0.001). Conclusions: Antimicrobial synergy between OligoG and nystatin against Candida spp. highlights the potential utility of this combination therapy in the prevention and topical treatment of candidal biofilm infections, to overcome the inherent tolerance of biofilm structures to antifungal agents.


Subject(s)
Antifungal Agents , Candidiasis , Humans , Antifungal Agents/pharmacology , Antifungal Agents/chemistry , Nystatin/pharmacology , Nystatin/metabolism , Alginates/pharmacology , Alginates/chemistry , Alginates/metabolism , Candida , Candidiasis/drug therapy , Candidiasis/microbiology , Candida tropicalis , Candida glabrata , Biofilms , Oligosaccharides/pharmacology , Oligosaccharides/chemistry , Adenosine Triphosphate/metabolism , Microbial Sensitivity Tests
3.
Proteins ; 89(5): 558-568, 2021 05.
Article in English | MEDLINE | ID: mdl-33389775

ABSTRACT

Polyene polyketides amphotericin B (AMB) and nystatin (NYS) are important antifungal drugs. Thioesterases (TEs), located at the last module of PKS, control the release of polyketides by cyclization or hydrolysis. Intrigued by the tiny structural difference between AMB and NYS, as well as the high sequence identity between AMB TE and NYS TE, we constructed four systems to study the structural characteristics, catalytic mechanism, and product release of AMB TE and NYS TE with combined MD simulations and quantum mechanics/molecular mechanics calculations. The results indicated that compared with AMB TE, NYS TE shows higher specificity on its natural substrate and R26 as well as D186 were proposed to a key role in substrate recognition. The energy barrier of macrocyclization in AMB-TE-Amb and AMB-TE-Nys systems were calculated to be 14.0 and 22.7 kcal/mol, while in NYS-TE-Nys and NYS-TE-Amb systems, their energy barriers were 17.5 and 25.7 kcal/mol, suggesting the cyclization with their natural substrates were more favorable than that with exchanged substrates. At last, the binding free energy obtained with the MM-PBSA.py program suggested that it was easier for natural products to leave TE enzymes after cyclization. And key residues to the departure of polyketide product from the active site were highlighted. We provided a catalytic overview of AMB TE and NYS TE including substrate recognition, catalytic mechanism and product release. These will improve the comprehension of polyene polyketide TEs and benefit for broadening the substrate flexibility of polyketide TEs.


Subject(s)
Amphotericin B/chemistry , Bacterial Proteins/chemistry , Nystatin/chemistry , Streptomyces/enzymology , Thiolester Hydrolases/chemistry , Amphotericin B/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Binding Sites , Biocatalysis , Catalytic Domain , Cyclization , Hydrogen Bonding , Hydrolysis , Hydrophobic and Hydrophilic Interactions , Isoenzymes/chemistry , Isoenzymes/genetics , Isoenzymes/metabolism , Kinetics , Models, Molecular , Molecular Dynamics Simulation , Mutation , Nystatin/metabolism , Protein Binding , Protein Conformation, alpha-Helical , Protein Conformation, beta-Strand , Protein Interaction Domains and Motifs , Quantum Theory , Streptomyces/chemistry , Substrate Specificity , Thermodynamics , Thiolester Hydrolases/genetics , Thiolester Hydrolases/metabolism
4.
AAPS PharmSciTech ; 19(4): 1574-1581, 2018 May.
Article in English | MEDLINE | ID: mdl-29484614

ABSTRACT

To promote transungual permeation of nystatin (NYST), molecule with high molecular weight, no water-soluble, amphoteric by iontophoresis. The synergic effect of the combination of cetylpyridinium chloride, CPC, or polyoxyethylene (20) sorbitan monooleate, TW80, and iontophoresis was investigated. In vitro permeation experiments were carried out through bovine hoof slices using vertical diffusion cells. A low current density (0.2 mA/cm2) was applied by introducing Ag/AgCl electrodes in the donor (anode) and receptor (cathode) chambers. The donor phase consisted of a solution, a suspension, or gel-type vehicles containing NYST and surfactants in pH 5.6 HEPES buffer. The addition of CPC to NYST suspension (SOSP) produced a fivefold increase on the permeability of the bovine hoof membrane to the drug. The application of anodal iontophoresis further improved NYST flux. Conversely, NYST transungual permeation was not influenced by TW80 either in the passive diffusion or iontophoretic flux. Furthermore, the iontophoretic treatment does not appear to induce irreversible alterations to the hoof bovine membranes. The present work demonstrated the efficacy of iontophoresis as a treatment for different nail pathologies with large molecules very slightly soluble in water without irreversibly affecting the nail structure. A synergistic effect between CPC and iontophoresis was observed.


Subject(s)
Hoof and Claw/drug effects , Hoof and Claw/metabolism , Iontophoresis/methods , Nystatin/chemistry , Nystatin/metabolism , Administration, Cutaneous , Animals , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/metabolism , Cattle , Dose-Response Relationship, Drug , Excipients/administration & dosage , Excipients/chemistry , Excipients/metabolism , Nystatin/administration & dosage , Permeability/drug effects
5.
J Ind Microbiol Biotechnol ; 44(9): 1293-1299, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28555391

ABSTRACT

NPP A1 produced by Pseudonocardia autotrophica is a unique disaccharide-containing polyene macrolide. NPP A1 was reported to have higher water solubility and lower hemolytic toxicity than nystatin A1 while retaining its antifungal activity. An engineered NPP A1 analogue, NPP A2, was generated by inactivation of the nppL gene, encoding a P450 monooxygenase in P. autotrophica. The resulting compound exhibited the corresponding chemical structure of NPP A1 but lacked a C10 hydroxyl group. In this study, newly developed crystallization recovery methods for NPP A2 purification, followed by an evaluation of in vitro antifungal activity and hemolytic activity, were performed. The crystallization methods were designed to eliminate the undesired viscous impurities encountered during the NPP A2 purification process, resulting in improved purity from 5.3 to 83.5% w/w. NPP A2 isolated from the improved purification process also exhibited two times higher antifungal activity and 1.8 times higher hemolytic toxicity than those of NPP A1. These results suggest that the minor structural modification of disaccharide-containing polyene macrolides, such as removing a C10 hydroxyl group, might require an alternative recovery process, such as crystallization, to confirm its improved biological activity.


Subject(s)
Actinomycetales/metabolism , Polyenes/chemistry , Polyenes/metabolism , Actinomycetales/chemistry , Actinomycetales/genetics , Antifungal Agents/chemistry , Antifungal Agents/metabolism , Disaccharides/metabolism , Hemolysis , Macrolides/chemistry , Macrolides/metabolism , Nystatin/metabolism
6.
Cell Rep ; 19(1): 20-35, 2017 04 04.
Article in English | MEDLINE | ID: mdl-28380358

ABSTRACT

Human pluripotent stem cells (hPSCs) have been reported in naive and primed states. However, the ability to generate mature cell types remains the imperative property for utility of hPSCs. Here, we reveal that the naive state enhances self-renewal while restricting lineage differentiation in vitro to neural default fate. Molecular analyses indicate expression of multiple lineage-associated transcripts in naive hPSCs that failed to predict biased functional differentiation capacity. Naive hPSCs can be converted to primed state over long-term serial passage that permits recovery of multi-germ layer differentiation. Suppression of OCT4 but not NANOG allows immediate recovery directly from naive state. To this end, we identified chemical inhibitors of OCT4 that restore naive hPSC differentiation. Our study reveals unique cell-fate restrictions in human pluripotent states and provides an approach to overcome these barriers that harness both efficient naive hPSC growth while maintaining in vitro differentiation essential for hPSC applications.


Subject(s)
Cell Differentiation/genetics , Cell Lineage/genetics , Cellular Reprogramming/genetics , Germ Layers/cytology , Pluripotent Stem Cells/cytology , Animals , Gene Expression Profiling , Gene Expression Regulation, Developmental , Hepatocytes/metabolism , Humans , Mice , Myocytes, Cardiac/metabolism , Nanog Homeobox Protein/metabolism , Nystatin/metabolism , Octamer Transcription Factor-3/metabolism , RNA/genetics , Teratoma/metabolism
7.
Int J Biol Macromol ; 96: 687-696, 2017 Mar.
Article in English | MEDLINE | ID: mdl-28041915

ABSTRACT

The complex pathophysiology involved in migraine necessitates the drug treatment to act on several receptors simultaneously. The present investigation was an attempt to discover the unidentified anti-migraine activity of the already marketed drugs. Shared featured pharmacophore modeling was employed for this purpose on six target receptors (ß2 adrenoceptor, Dopamine D3, 5HT1B, TRPV1, iGluR5 kainate and CGRP), resulting in the generation of five shared featured pharmacophores, which were further subjected to virtual screening of the ligands obtained from Drugbank database. Molecular docking, performed on the obtained hit compounds from virtual screening, indicated nystatin to be the only active lead against the receptors iGluR5 kainate receptor (1VSO), CGRP (3N7R), ß2 adrenoceptor (3NYA) and Dopamine D3 (3PBL) with a high binding energy of -11.1, -10.9, -10.2 and -12kcal/mole respectively. The anti-migraine activity of nystatin was then adjudged by fabricating its brain targeted chitosan nanoparticles. Its brain targeting efficacy, analyzed qualitatively by confocal laser scanning microscopy, demonstrated a significant amount of drug reaching the brain. The pharmacodynamic models on Swiss male albino mice revealed significant anti-migraine activity of the nanoformulation. The present study reports for the first time the therapeutic potential of nystatin in migraine management, hence opening avenues for its future exploration.


Subject(s)
Brain/drug effects , Chitosan/chemistry , Drug Carriers/chemistry , Migraine Disorders/drug therapy , Nanoparticles/chemistry , Nystatin/chemistry , Nystatin/pharmacology , Animals , Bradykinin/pharmacology , Brain/metabolism , Drug Evaluation, Preclinical , Drug Liberation , Grooming/drug effects , Hyperalgesia/complications , Male , Mice , Migraine Disorders/complications , Migraine Disorders/metabolism , Molecular Docking Simulation , Molecular Targeted Therapy , Nystatin/metabolism , Nystatin/therapeutic use , Particle Size , Photophobia/chemically induced , Photophobia/complications , Protein Conformation , Software
8.
Carbohydr Polym ; 117: 140-149, 2015 Mar 06.
Article in English | MEDLINE | ID: mdl-25498619

ABSTRACT

To develop more effective antifungal mucoadhesive systems for the treatment of oral candidiasis, three types of microspheres, alginate (AM1), chitosan coated (CCM) and hydrogel (AM2) containing nystatin (Nys) were successfully elaborated by emulsification/internal gelation method. Physicochemical properties of microspheres resulted in 85-135 µm mean sizes, spherical shaped with narrow distribution. Optimal encapsulation efficiency and negative zeta potentials were observed. AM2 showed a consistent decrease in viscosity with increasing shear rate (Herschel-Bulkley). Optimal mucoadhesive properties and swelling behaviour where evidenced. Nys release from AM1 and CCM followed a concentration gradient pattern, contrary AM2 followed a complex release mechanism. All systems exhibited a marked fungicidal activity against Candida albicans strains. In vivo studies demonstrated that Nys was not found in systemic circulation assuring the safety of the treatment. Nys amounts retained in the mucosa were more than enough to ensure an effective fungicidal action without tissue damage. Based on the obtained results, AM2 could be proposed as the vehicle with the best properties for the buccal vehiculization of Nys.


Subject(s)
Adhesives/chemistry , Alginates/chemistry , Drug Carriers/chemistry , Microspheres , Mouth Mucosa/metabolism , Nystatin/chemistry , Nystatin/pharmacology , Absorption, Physicochemical , Animals , Antifungal Agents/chemistry , Antifungal Agents/metabolism , Antifungal Agents/pharmacology , Candida albicans/drug effects , Chitosan/chemistry , Drug Liberation , Female , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Hydrogels/chemistry , Nystatin/metabolism , Swine
9.
Med Chem ; 10(4): 348-54, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24725140

ABSTRACT

The antitumor activity of antibacterial and antifungal compounds has been of interest in the past. In several investigations glycopeptide antibiotics like bleomycin and antifungal agents like itraconazole have shown direct positive results whereas antifungal polyenes such as amphotericin B have been shown to potentiate the effects of antitumor agents. After having investigated the fluorescence-marked antibacterial glycopeptides vancomycin and ramoplanin on various malignant and healthy human cells in previous studies, the present work is focused on the antifungal polyene nystatin. We coupled nystatin to the fluorescent dye fluorescein isothiocyanate (FITC). After confirming the correct mass by mass spectrometry the effect of the conjugate on nine different human cell lines (two benign and seven tumor cell lines) was examined. The character of the uptake was determined by confocal laser scanning microscopy (CLSM) and the uptake was quantified by fluorescence activated cell sorting (FACS). The addition of propidium iodide (PI) allowed for detection and quantification of cell membrane disruption caused by the fluorescein-nystatin conjugate. Uptake of the conjugate was found to vary among the nine cell lines investigated. Conjugate uptake was strongest after 6 hours in most cell lines. Only the two prostate carcinoma cell lines PC3 and LNCaP showed further increase in uptake after long-time (24h) incubation. PI staining in general correlated well with the conjugate FITC staining values. The Colo205 colon carcinoma cell line and the U373 and LN18 glioblastoma cell lines exhibited very low conjugate uptake and PI staining. The results indicate that this conjugate shows potential for future imaging studies on certain human cancer cells.


Subject(s)
Antifungal Agents/chemistry , Fluorescein-5-isothiocyanate/chemistry , Molecular Imaging/methods , Nystatin/chemistry , Antifungal Agents/analysis , Antifungal Agents/metabolism , Cell Line , Flow Cytometry , Fluorescein-5-isothiocyanate/analysis , Fluorescein-5-isothiocyanate/metabolism , Fluorescence , Fluorescent Dyes/analysis , Fluorescent Dyes/chemistry , Fluorescent Dyes/metabolism , HEK293 Cells , HeLa Cells , Humans , Microscopy, Confocal , Molecular Structure , Nystatin/analysis , Nystatin/metabolism
10.
FEBS J ; 281(8): 2051-60, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24612537

ABSTRACT

The dependence of membrane function on its sterol component has been intensively studied with model lipids and isolated animal membranes, but to a much lesser extent with plant membranes. Depleting membrane sterols could be predicted to have a strong effect on membrane activity and have harmful physiological consequences. In this study, we characterized membrane lipid composition, membrane permeability for ions, some physiological parameters, such as H2O2 accumulation, formation of autophagosomal vacuoles, and expression of peroxidase and autophagic genes, and cell viability in the roots of wheat (Triticum aestivum L.) seedlings in the presence of two agents that specifically bind to endogenous sterols. The polyene antibiotic nystatin binds to endogenous sterols, forming so-called 'nystatin pores' or 'channels' in the membrane, and methyl-ß-cyclodextrin has the capacity to sequester sterols in its hydrophobic core. Unexpectedly, although application of both methyl-ß-cyclodextrin and nystatin reduced the sterol content, their effects on membrane permeability, oxidative status and autophagosome formation in roots differed dramatically. For comparison, we also tested the effects of the antibiotic gramicidin S, which does not bind to sterols but forms nonspecific channels in the membrane. Gramicidin S considerably increased membrane permeability, caused oxidative stress, and reduced cell viability. Our results suggest that a decrease in the sterol content is, in itself, not sufficient to have deleterious effects on a cell. The disturbance of membrane integrity, rather than the decrease in the sterol content, is responsible for the toxicity of sterol-binding compounds.


Subject(s)
Nystatin/metabolism , Phytosterols/metabolism , beta-Cyclodextrins/metabolism , Plant Roots/chemistry , Triticum/chemistry
11.
Rev. iberoam. micol ; 29(1): 20-23, ene.-mar. 2012.
Article in Spanish | IBECS | ID: ibc-96546

ABSTRACT

Antecedentes. La estomatitis protética es la forma más común de infección bucal producida por especies de Candida, siendo Candida albicans el agente etiológico más común. Diversos autores han intentado asociar agentes antifúngicos o antisépticos a los materiales de revestimiento blando o a las resinas acrílicas de las prótesis dentales, pero sin éxito. Por ello, se ha investigado un compuesto de amonio cuaternario (2-metacriloil oxietil trimetilamonio [MADQUAT]), que copolimeriza con los metacrilatos y que podría actuar como inhibidor de levaduras. Objetivos. El objetivo de este estudio fue evaluar la actividad in vitro del MADQUAT contra especies de Candida. Métodos. Se utilizaron 31 cepas de Candida para determinar la actividad antifúngica in vitro. Se determinó la concentración mínima inhibitoria (CMI) y la concentración mínima fungicida del MADQUAT, así como de la nistatina. Resultados. El MADQUAT presentó propiedades antifúngicas en las concentraciones entre 6,25 y > 100mg/ml y actividad fungicida entre 25 y > 100mg/ml. Los estudios cuantitativos de la actividad fungistática y fungicida del MADQUAT demostraron actividad fungistática contra todas las cepas de Candida albicans, Candida krusei y Candida parapsilosis, revelando actividad fungicida contra algunas cepas de otras especies. Conclusiones. El MADQUAT presenta actividad antifúngica contra Candida spp. Además, la sensibilidad a dicho compuesto es distinta entre las diferentes especies considerando los valores de la CMI y la actividad fungicida o fungistática(AU)


Background. Candida-associated denture stomatitis is the most common manifestation of oral candidal infection, caused mainly by Candida albicans. Several authors have attempted to add antifungal agents or antiseptics to denture temporary soft lining materials or to denture acrylic resins, without relevant results. Therefore, the investigation of a quaternary ammonium functionalized compound [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT), which copolymerizes with methacrylates and which could act as a fungal inhibitor, is of paramount importance. Aims. To evaluate the in vitro activity of MADQUAT against Candida species. Methods. Thirty-one Candida strains were used to determine the in vitro antifungal activity of this compound. The minimum inhibitory concentrations and minimum fungicidal concentrations of MADQUAT and nystatin were determined. Results. MADQUAT showed antifungal properties at concentrations of 6.25 to > 100mg/ml, and fungicidal activity between 25 and > 100mg/ml. The quantitative determinations of the fungistatic and fungicidal activity of MADQUAT showed fungistatic activity against all Candida albicans, Candida krusei and Candida parapsilosis strains, revealing fungicidal activity against some strains of the other species. Conclusions. MADQUAT has antifungal activity against Candida spp. Moreover, the sensitivity to this substance varies across the different species in terms of MIC values and fungicidal or fungistatic activity(AU)


Subject(s)
Products with Antimicrobial Action , Cetrimonium Compounds/therapeutic use , Trimethyl Ammonium Compounds/therapeutic use , Candida/isolation & purification , Candida/pathogenicity , Nystatin/therapeutic use , Mycology/methods , Microbial Sensitivity Tests/methods , Microbial Sensitivity Tests/trends , Sensitivity and Specificity , Candida , Candida/enzymology , Nystatin/metabolism , Microbial Sensitivity Tests/standards
12.
Appl Environ Microbiol ; 77(18): 6636-43, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21764946

ABSTRACT

Polyene macrolide antibiotics, including nystatin and amphotericin B, possess fungicidal activity and are being used as antifungal agents to treat both superficial and invasive fungal infections. Due to their toxicity, however, their clinical applications are relatively limited, and new-generation polyene macrolides with an improved therapeutic index are highly desirable. We subjected the polyol region of the heptaene nystatin analogue S44HP to biosynthetic engineering designed to remove and introduce hydroxyl groups in the C-9-C-10 region. This modification strategy involved inactivation of the P450 monooxygenase NysL and the dehydratase domain in module 15 (DH15) of the nystatin polyketide synthase. Subsequently, these modifications were combined with replacement of the exocyclic C-16 carboxyl with the methyl group through inactivation of the P450 monooxygenase NysN. Four new polyene macrolides with up to three chemical modifications were generated, produced at relatively high yields (up to 0.51 g/liter), purified, structurally characterized, and subjected to in vitro assays for antifungal and hemolytic activities. Introduction of a C-9 hydroxyl by DH15 inactivation also blocked NysL-catalyzed C-10 hydroxylation, and these modifications caused a drastic decrease in both antifungal and hemolytic activities of the resulting analogues. In contrast, single removal of the C-10 hydroxyl group by NysL inactivation had only a marginal effect on these activities. Results from the extended antifungal assays strongly suggested that the 9-hydroxy-10-deoxy S44HP analogues became fungistatic rather than fungicidal antibiotics.


Subject(s)
Antifungal Agents/metabolism , Biosynthetic Pathways/genetics , Macrolides/metabolism , Nystatin/analogs & derivatives , Polyenes/metabolism , Streptomyces/genetics , Streptomyces/metabolism , Animals , Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Antifungal Agents/toxicity , Candida albicans/drug effects , Erythrocytes/drug effects , Hemolysis , Horses , Macrolides/chemistry , Macrolides/pharmacology , Macrolides/toxicity , Magnetic Resonance Spectroscopy , Microbial Sensitivity Tests , Models, Molecular , Molecular Structure , Nystatin/chemistry , Nystatin/metabolism , Nystatin/pharmacology , Nystatin/toxicity , Polyenes/chemistry , Polyenes/pharmacology , Polyenes/toxicity , Polymers/chemistry , Polymers/metabolism , Streptomyces/enzymology
13.
J Ind Microbiol Biotechnol ; 38(4): 573-9, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21259033

ABSTRACT

Using the genomics-guided polyene screening method, a rare actinomycetes called Pseudonocardia autotrophica was previously identified to contain functionally clustered nystatin-like biosynthetic genes and to produce a presumably novel polyene compound named nystatin-like Pseudonocardia polyene (NPP) (Kim et al., J Ind Microbiol Biotechnol 36:1425-1434, 2009). Since very low NPP productivity was observed in most P. autotrophica culture conditions, its biosynthetic pathway was proposed to be tightly regulated. Herein we report in silico analysis of six putative NPP pathway-specific regulatory genes present in its biosynthetic gene cluster, followed by functional overexpression of these regulatory genes in P. autotrophica. Three pathway-specific regulatory genes (nppRI, RIII, and RV) were predicted to belong to a typical LAL-type transcriptional family. Each regulatory gene was cloned under the strong constitutive ermE* promoter in a Streptomyces integrative pSET152 plasmid, followed by direct intergeneric conjugation from a plasmid-containing E. coli donor cell to P. autotrophica. While all the P. autotrophica exconjugants exhibited improved NPP productivity, the one containing nppRIII showed the highest NPP productivity improvement. In addition, culture-time-dependent analysis revealed that the nppRIII-stimulated NPP biosynthesis was more significant in the late exponential growth stage than in the stationary stage. Moreover, the P. autotrophica nppRIII-disruption mutant failed to produce NPP, with significantly reduced transcription levels of most npp biosynthetic genes. The results described suggest that identification and overexpression of key pathway-specific regulatory gene, followed by optimum harvest timing, should be critical factors to maximize the productivity of an intrinsically low-level metabolite such as NPP produced by rare actinomycetes species.


Subject(s)
Actinomycetales/genetics , Macrolides/metabolism , Actinomycetales/metabolism , Amino Acid Sequence , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Biosynthetic Pathways/genetics , Genes, Regulator , Molecular Sequence Data , Nystatin/metabolism , Polyenes/metabolism , Sequence Alignment
14.
Int Microbiol ; 13(1): 1-7, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20890834

ABSTRACT

This article reviews the latest findings on how extracellular signaling controls cell fate determination during the process of biofilm formation by Bacillus subtilis in the artificial setting of the laboratory. To complement molecular genetic approaches, surface-associated communities in settings as diverse as the pitcher plant Sarracenia purpurea and the human lung were investigated. The study of the pitcher plant revealed that the presence or absence of a mosquito larva in the pitcher plant controlled bacterial diversity in the ecosystem inside the pitcher plant. Through the analysis of the respiratory tract microbiota of humans suffering from cystic fibrosis (CF) a correlation between lung function and bacterial community diversity was found. Those that had lungs in good condition had also more diverse communities, whereas patients harboring Pseudomonas aeruginosa-the predominant CF pathogen-in their lungs had less diverse communities. Further studies focused on interspecies and intraspecies relationships at the molecular level in search for signaling molecules that would promote biofilm formation. Two molecules were found that induced biofilm formation in B. subtilis: nystatin-released by other species-and surfactin-released by B. subtilis itself. This is a role not previously known for two molecules that were known for other activities-nystatin as an antifungal and surfactin as a surfactant. In addition, surfactin was found to also trigger cannibalism under starvation. This could be a strategy to maintain the population because the cells destroyed serve as nutrients for the rest. The path that led the author to the study of microbial biofilms is also described.


Subject(s)
Bacteria/growth & development , Bacterial Physiological Phenomena , Biodiversity , Ecosystem , Antifungal Agents/metabolism , Bacteria/metabolism , Biofilms/growth & development , Lipopeptides/metabolism , Lung/microbiology , Nystatin/metabolism , Peptides, Cyclic/metabolism , Sarraceniaceae/microbiology , Signal Transduction , Surface-Active Agents/metabolism
15.
Int. microbiol ; 13(1): 1-7, mar. 2010. ilus
Article in English | IBECS | ID: ibc-87666

ABSTRACT

This article reviews the latest findings on how extracellular signaling controls cell fate determination during the process of biofilm formation by Bacillus subtilis in the artificial setting of the laboratory. To complement molecular genetic approaches, surface-associated communities in settings as diverse as the pitcher plant Sarracenia purpurea and the human lung were investigated. The study of the pitcher plant revealed that the presence or absence of a mosquito larva in the pitcher plant controlled bacterial diversity in the ecosystem inside the pitcher plant. Through the analysis of the respiratory tract microbiota of humans suffering from cystic fibrosis (CF) a correlation between lung function and bacterial community diversity was found. Those that had lungs in good condition had also more diverse communities, whereas patients harboring Pseudomonas aeruginosa-the predominant CF pathogen-in their lungs had less diverse communities. Further studies focused on interspecies and intraspecies relationships at the molecular level in search for signaling molecules that would promote biofilm formation. Two molecules were found that induced biofilm formation in B. subtilis: nystatin-released by other species-and surfactin-released by B. subtilis itself. This is a role not previously known for two molecules that were known for other activities-nystatin as an antifungal and surfactin as a surfactant. In addition, surfactin was found to also trigger cannibalism under starvation. This could be a strategy to maintain the population because the cells destroyed serve as nutrients for the rest. The path that led the author to the study of microbial biofilms is also described (AU)


No disponible


Subject(s)
Bacteria/growth & development , Biodiversity , Ecosystem , Antifungal Agents/metabolism , Bacteria/metabolism , Biofilms/growth & development , Lung/microbiology , Nystatin/metabolism , Peptides, Cyclic/metabolism , Sarraceniaceae/microbiology , Signal Transduction , Surface-Active Agents/metabolism
16.
Int J Pharm ; 386(1-2): 1-5, 2010 Feb 15.
Article in English | MEDLINE | ID: mdl-19874880

ABSTRACT

A new targeted intravenous conjugate of nystatin with pentaerythritol poly(ethylene glycol)ether has been prepared and characterised (NY(4)-sPEG, M=25 160). The conjugate contains a beta-d-glucopyranoside molecular switch sensitive to beta-glucosidases (E.C.3.2.1.21), which are specifically present in the enzyme outfit of fungal pathogens. The investigated conjugate is stable under in vitro conditions for 24h (solution of phosphate buffer pH=7.4). Spectrophotometrically controlled releasing of nystatin in model medium containing beta-glucosidase ((Aspergillus niger) 2mg/mL, 66.6 units/g; pH 7.4, 2 x 10(-2)M), reported decomposition half-life of conjugate tau(1/2)=(88+/-2)s. This implies that releasing of nystatin is controlled only enzymatically.


Subject(s)
Antifungal Agents/chemistry , Aspergillus niger/enzymology , Cellulases/metabolism , Drug Carriers , Nystatin/administration & dosage , Polyethylene Glycols/chemistry , Propylene Glycols/chemistry , Antifungal Agents/administration & dosage , Antifungal Agents/metabolism , Buffers , Cellulases/isolation & purification , Chemistry, Pharmaceutical , Chromatography, Gel , Chromatography, High Pressure Liquid , Delayed-Action Preparations , Drug Compounding , Drug Stability , Half-Life , Hydrogen-Ion Concentration , Hydrolysis , Kinetics , Magnetic Resonance Spectroscopy , Nystatin/chemistry , Nystatin/metabolism , Solubility , Spectrophotometry, Ultraviolet , Technology, Pharmaceutical/methods
17.
Cancer Res ; 69(13): 5610-7, 2009 Jul 01.
Article in English | MEDLINE | ID: mdl-19509228

ABSTRACT

Ovarian cancer is the most lethal gynecologic malignancy, often diagnosed at advanced stage leading to poor prognosis. In the study reported here, magnetic resonance imaging and near-infrared reflectance imaging were applied for in vivo analysis of two competing endocytic pathways affecting retention of bifunctional daidzein-bovine serum albumin (BSA)-based contrast media by human epithelial ovarian carcinoma cells. Suppression of caveolae-mediated uptake using nystatin or by BSA competition significantly enhanced daidzein-BSA-GdDTPA/CyTE777 uptake by tumor cells in vitro. In vivo, perivascular myofibroblasts generated an effective perivascular barrier excluding delivery of BSA-GdDTPA/CyTE777 to tumor cells. The ability to manipulate caveolae-mediated sequestration of albumin by perivascular tumor myofibroblasts allowed us to effectively overcome this tumor-stroma barrier, increasing delivery of daidzein-BSA-GdDTPA/CyTE777 to the tumor cells in tumor xenografts. Thus, both in vitro and in vivo, endocytosis of daidzein-BSA-GdDTPA/CyTE777 by ovarian carcinoma cells was augmented by albumin or by nystatin. In view of the cardinal role of albumin in affecting the availability and pharmacokinetics of drugs, this approach could potentially also facilitate the delivery of therapeutics and contrast media to tumor cells.


Subject(s)
Endocytosis/physiology , Ovarian Neoplasms/blood , Ovarian Neoplasms/pathology , Animals , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/therapeutic use , Biological Transport , Female , Humans , Isoflavones/metabolism , Isoflavones/pharmacokinetics , Mice , Mice, Nude , Nystatin/metabolism , Ovarian Neoplasms/drug therapy , Pentetic Acid/metabolism , Serum Albumin, Bovine/pharmacokinetics , Tissue Distribution
19.
J Pharm Sci ; 98(2): 555-64, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18563796

ABSTRACT

The purpose of the present study was to design and evaluate a novel vaginal delivery system for nystatin based on mucoadhesive polymers. L-Cysteine and cysteamine, respectively, were covalently attached to poly(acrylic acid), and the two different thiolated polymers were evaluated in vitro regarding their swelling behavior, mucoadhesive properties and release behavior. Tablets comprising these thiolated polymers and nystatin demonstrated a high stability in vaginal fluid simulant pH 4.2 and an increase in weight by swelling whereas control tablets comprising unmodified poly(acrylic acid) disintegrated and dissolved. The mucoadhesion time of tablets on freshly excised bovine vaginal mucosa on a rotating cylinder and the total work of adhesion of gels and tablets increased significantly due to the formation of disulfide bonds between the thiolated polymer and cysteine rich subdomaines of the mucus layer. The drug nystatin was released more slowly out of thiomer tablets and gels than out of PAA control tablets and gels. Therefore these thiolated polymers are promising delivery systems for nystatin providing a prolonged residence time and a sustained drug release in vitro under physiological relevant conditions.


Subject(s)
Anti-Infective Agents/chemistry , Cysteamine/chemistry , Cysteine/chemistry , Drug Carriers , Mucins/chemistry , Nystatin/chemistry , Acrylic Resins/chemistry , Adhesiveness , Administration, Intravaginal , Animals , Anti-Infective Agents/administration & dosage , Anti-Infective Agents/metabolism , Cattle , Chemistry, Pharmaceutical , Delayed-Action Preparations , Drug Compounding , Drug Stability , Female , Gels , Hydrogen-Ion Concentration , Kinetics , Mucous Membrane/metabolism , Nystatin/administration & dosage , Nystatin/metabolism , Oscillometry , Particle Size , Rheology , Solubility , Tablets , Tensile Strength , Vagina/metabolism
20.
Anal Sci ; 24(12): 1551-6, 2008 Dec.
Article in English | MEDLINE | ID: mdl-19075463

ABSTRACT

The colloid osmotic nature of the cell lysis can be prevented by adding osmotic protectants of appropriate sizes to the outer medium. We introduced inorganic and organic electrolytes as protectants to determine the precise channel sizes of the polyene antibiotics, amphotericin B and nystatin, in addition to the sugars so far widely used for this purpose. Because colloid osmotic cell lysis is evidenced by the loss of membrane permeability barriers for small sizes of ions, such as K(+), preceding hemolysis, we firstly simultaneously monitored the time response of the K(+) efflux and hemolysis induced by amphotericin B by combining a fiber-optic spectrometer with a K(+)-selective electrode. Based on this experiment, we evaluated the sizes of channels of the polyene antibiotics formed in the erythrocyte membrane using the radii of hydrated ions calculated from a modified Stokes' law, as well as the radii of sugars. The radii of channels formed by amphotericin B and nystatin were found to be in a very narrow range of 0.36 - 0.37 nm. Similar experiments were performed using calcein-loaded liposomes containing cholesterol or ergosterol, and the radii of channels formed in these liposomal membranes were also found to be the same as when formed in an erythrocyte membrane. The present results demonstrated that introducing the sizes of hydrated ions can afford a more precise channel size than the use of sugars alone.


Subject(s)
Amphotericin B/chemistry , Amphotericin B/metabolism , Erythrocytes/metabolism , Liposomes/chemistry , Liposomes/metabolism , Nystatin/chemistry , Nystatin/metabolism , Osmosis , Animals , Carbohydrates/pharmacology , Electrolytes/pharmacology , Erythrocytes/chemistry , Hemolysis/drug effects , Osmosis/drug effects , Potassium/metabolism , Sheep , Time Factors , Water/metabolism
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