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1.
Int J Mol Sci ; 23(23)2022 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-36499133

RESUMO

For the effective clinical antibacterial application of biomaterials, such as for wound management and tissue repair, the biomaterials need to show proper antibacterial capability as well as non-cytotoxicity. Furthermore, the material needs to have suitable mechanical characteristics for further medical use. Chitosan hydrogel is a potential candidate for various antibacterial biomedical applications due to its amine functionalities that lead to antimicrobial characteristics. Nevertheless, its antimicrobial capability is dependent upon the degree of protonation of amine groups caused by the pH value. Moreover, its mechanical compressive strength may not be high enough for clinical use if not chemically or physically crosslinked. This study utilized a novel chemical crosslinker, mercaptosuccinic acid, to improve its mechanical characteristics. The natural antibacterial agent, cinnamaldehyde, was grafted onto the crosslinked chitosan to improve its antimicrobial capability. Meanwhile, to take advantage of the thiol functionality in the mercaptosuccinic acid, the bactericidal silver nanoparticles were incorporated through silver-thiol covalent bounding. NMR analyses indicated the chitosan was successfully mercaptosuccinic acid-crosslinked and grafted with cinnamaldehyde at different ratios. Combined the results from the mechanical assessment, swelling experiments, antimicrobial assessment, and cytotoxicity assay, the chitosan hydrogel with the highest crosslinked degree and grafted with cinnamaldehyde and silver nanoparticles is of great promise for further clinical uses.


Assuntos
Quitosana , Nanopartículas Metálicas , Quitosana/química , Hidrogéis/química , Prata/química , Nanopartículas Metálicas/química , Antibacterianos/farmacologia , Antibacterianos/química , Tiomalatos , Aminas
2.
Analyst ; 147(20): 4553-4561, 2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36102749

RESUMO

A hydrophilic interaction chromatography (HILIC) strategy is considered as an efficient strategy for efficient glycopeptide enrichment. Here, a novel hydrophilic material (denoted as magCDP@Ada-MSA) was constructed through host-guest interaction between crosslinked ß-cyclodextrin (ß-CD) polymers and mercaptosuccinic acid (MSA) derived adamantane. On the one hand, crosslinked ß-CD polymers have great hydrophilicity due to their abundant hydrophilic hydroxyl groups. On the other hand, the hydrophilic functional molecule MSA was introduced into crosslinked ß-CD polymers through host-guest interaction for further hydrophilic modification of the material. Hydroxyl groups in crosslinked ß-CD polymers and carboxyl groups in MSA together endow the material with excellent hydrophilicity and good affinity toward glycopeptides. The prepared hydrophilic material demonstrated rapid magnetic separation (within 5 s) and reusability (at least 10 cycles). Thanks to the above advantages, magCDP@Ada-MSA showed satisfactory performance for the specific enrichment of glycopeptides (selectivity, 1 : 500 molar ratios of HRP/BSA and sensitivity, 0.1 fmol µL-1). Moreover, magCDP@Ada-MSA was successfully applied for selective glycopeptide enrichment from complex biological samples (human serum and saliva).


Assuntos
Adamantano , beta-Ciclodextrinas , Celulose , Ciclodextrinas , Glicopeptídeos/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Polímeros/química , Tiomalatos
3.
Molecules ; 25(18)2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32916994

RESUMO

The control of leishmaniases, a complex parasitic disease caused by the protozoan parasite Leishmania, requires continuous innovation at the therapeutic and vaccination levels. Chitosan is a biocompatible polymer administrable via different routes and possessing numerous qualities to be used in the antileishmanial strategies. This review presents recent progress in chitosan research for antileishmanial applications. First data on the mechanism of action of chitosan revealed an optimal in vitro intrinsic activity at acidic pH, high-molecular-weight chitosan being the most efficient form, with an uptake by pinocytosis and an accumulation in the parasitophorous vacuole of Leishmania-infected macrophages. In addition, the immunomodulatory effect of chitosan is an added value both for the treatment of leishmaniasis and the development of innovative vaccines. The advances in chitosan chemistry allows pharmacomodulation on amine groups opening various opportunities for new polymers of different size, and physico-chemical properties adapted to the chosen routes of administration. Different formulations have been studied in experimental leishmaniasis models to cure visceral and cutaneous leishmaniasis, and chitosan can act as a booster through drug combinations with classical drugs, such as amphotericin B. The various architectural possibilities given by chitosan chemistry and pharmaceutical technology pave the way for promising further developments.


Assuntos
Antiprotozoários/administração & dosagem , Quitosana/química , Portadores de Fármacos/química , Vacinas contra Leishmaniose/administração & dosagem , Leishmaniose/tratamento farmacológico , Anfotericina B/química , Anfotericina B/farmacologia , Animais , Antimônio/química , Antiprotozoários/farmacologia , Materiais Biocompatíveis/química , Curcumina/química , Composição de Medicamentos , Humanos , Concentração de Íons de Hidrogênio , Vacinas contra Leishmaniose/química , Macrófagos/efeitos dos fármacos , Nanopartículas/química , Paromomicina/química , Triterpenos Pentacíclicos/química , Polímeros/química , Rifampina/química , Selênio/química , Tiomalatos/química , Titânio/química , Triterpenos/química , Ácido Betulínico
4.
ACS Appl Mater Interfaces ; 12(37): 41011-41025, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32840353

RESUMO

Ultrasmall silver nanoparticles (AgNPs; size < 3 nm) have attracted a great deal of interest as an alternative to commercially available antibiotics due to their ability to eliminate a wide range of microbial pathogens. However, most of these ultrasmall AgNPs are highly reactive and unstable, as well as susceptible to fast oxidation. Therefore, both the stability and toxicity remain major shortcomings for their clinical application and uptake. To circumvent these problems, we present a novel strategy to impregnate ultrasmall AgNPs into a biocompatible thermosensitive hydrogel that enables controlled release of silver alongside long-term storage stability and highly potent antibacterial activity. The advantage of this strategy lies in the combination of a homogenous dispersion of AgNPs in a hydrogel network, which serves as a sustained-release reservoir, and the unique feature of ultrasmall AgNP size, which provides an improved biofilm eradication capacity. The superior biofilm dispersion properties of the AgNP hydrogel is demonstrated in both single-species and multispecies biofilms, eradicating ∼80% of established biofilms compared to untreated controls. Notably, the effective antibacterial concentration of the formulation shows minimal toxicity to human fibroblasts and keratinocytes. These findings present a promising novel strategy for the development of AgNP hydrogels as an efficient antibacterial platform to combat resistant bacterial biofilms associated with wound infections.


Assuntos
Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Hidrogéis/farmacologia , Nanopartículas Metálicas/química , Prata/farmacologia , Tiomalatos/farmacologia , Antibacterianos/química , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Biofilmes/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Humanos , Hidrogéis/síntese química , Hidrogéis/química , Queratinócitos/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Pseudomonas aeruginosa/efeitos dos fármacos , Prata/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Propriedades de Superfície , Tiomalatos/síntese química , Tiomalatos/química
5.
Sci Rep ; 9(1): 17371, 2019 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-31758079

RESUMO

Polymeric nanoparticles have emerged as carrier systems for molecules that release nitric oxide (NO), a free radical involved in plant stress responses. However, to date, nanoencapsulated NO donors have not been applied to plants under realistic field conditions. Here, we verified the effects of free and nanoencapsulated NO donor, S-nitroso-mercaptosuccinic acid (S-nitroso-MSA), on growth, physiological and biochemical parameters of neotropical tree seedlings kept under full sunlight in the nursery for acclimation. S-nitroso-MSA incorporation into chitosan nanoparticles partially protected the NO donor from thermal and photochemical degradation. The application of nanoencapsulated S-nitroso-MSA in the substrate favoured the growth of seedlings of Heliocarpus popayanensis, a shade-intolerant tree. In contrast, free S-nitroso-MSA or nanoparticles containing non-nitrosated mercaptosuccinic acid reduced photosynthesis and seedling growth. Seedlings of Cariniana estrellensis, a shade-tolerant tree, did not have their photosynthesis and growth affected by any formulations, despite the increase of foliar S-nitrosothiol levels mainly induced by S-nitroso-MSA-loaded nanoparticles. These results suggest that depending on the tree species, nanoencapsulated NO donors can be used to improve seedling acclimation in the nursery.


Assuntos
Aclimatação , Nanopartículas/metabolismo , Doadores de Óxido Nítrico/administração & dosagem , Doadores de Óxido Nítrico/farmacocinética , Óxido Nítrico/farmacocinética , Plântula/metabolismo , Luz Solar , Aclimatação/efeitos dos fármacos , Aclimatação/fisiologia , Aclimatação/efeitos da radiação , Portadores de Fármacos , Composição de Medicamentos , Liberação Controlada de Fármacos , Jardins , Nanopartículas/química , Doadores de Óxido Nítrico/farmacologia , Fotossíntese/fisiologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , S-Nitrosotióis/administração & dosagem , S-Nitrosotióis/química , S-Nitrosotióis/farmacocinética , S-Nitrosotióis/farmacologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Tiomalatos/administração & dosagem , Tiomalatos/farmacocinética , Tiomalatos/farmacologia , Árvores/efeitos dos fármacos , Árvores/metabolismo , Árvores/efeitos da radiação , Clima Tropical
6.
J Photochem Photobiol B ; 199: 111629, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31610433

RESUMO

The water-soluble semiconductor quantum dots (QDs) serve as optically detectable models of nanoparticles and are commonly applied as photoluminescent markers in biological systems. The unicellular algae represent a popular model system suitable to evaluate pollution-induced effects. There is growing experimental evidence that release of metal ions cannot account for potential toxicity of metal containing nanoparticles, however, the underlying mechanisms are not clearly understood. Surrounding environment and illumination conditions are among the most important factors affecting the stability of QDs as well as the interaction between nanoparticles and cells such as microalgae. The measurements of changes in photoluminescence (PL) of QDs and autofluorescence (AF) of microalgae can thus be used as a non-invasive screening method for detecting mutual effects of nanoparticles and algae cells on each other under natural conditions. In this study, CdTe quantum dots (a peak of PL at 550 nm) capped with a mercaptosuccinic acid (MSA) were introduced into aqueous ionic medium containing wild type green freshwater microalgae Scenedesmus and Chlorella sp. cells under artificial and natural ambient illumination. The spectroscopy and microscopy techniques were applied to observe both the influence of the microalgae on the spectral properties of negatively charged CdTe-MSA quantum dots and the effects of nanoparticles on the microalgae. The presence of algae cells revealed a protecting effect on both medium-dependent and radiation-induced changes in photoluminescence properties of QDs, which could be related with the increased stability of the capping layer. The effects on cellular AF intensity and the interaction of QDs with cellular surface depended on type of microalgae. The observed changes in AF spectral properties and AF induction signals can't be explained only by the photodegradation of QDs and have revealed the ability of nanoparticles to retard the photoadaptation of wild type microalgae under naturally varying illumination conditions.


Assuntos
Compostos de Cádmio/química , Corantes Fluorescentes/química , Microalgas/metabolismo , Pontos Quânticos/química , Telúrio/química , Tiomalatos/química , Chlorella/metabolismo , Água Doce , Luz , Scenedesmus/metabolismo , Espectrometria de Fluorescência , Propriedades de Superfície
7.
Pharmazie ; 74(9): 536-542, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31484593

RESUMO

Glutathione peroxidase (GPx), an important antioxidative enzmye, can be inhibited by various thiols, including of tiopronin and mercaptosuccinic acid (MSA). Recently, there has been discussion regarding the combination of tiopronin in anticancer therapy to overcome acquired resistance to anticancer drugs. However, thiols are also known to act as antioxidants, which can be contraindicated in cancer chemotherapy. This article focuses on the inhibitory effects of tiopronin and MSA on bovine and human glutathione peroxidase activities, and their effects on the redox status of cancer cells. IC50 values for the inhibition for the bovine erythrocyte enzyme were 356 and 24.7 µM for tiopronin and MSA, respectively, with the corresponding Ki values of 343 µM and 14.6 µM, respectively at pH 7.4 and 25 °C. MSA inhibited human GPx activity in human cancer cell lysates at its IC50 while tiopronin did not. Both compounds were cytotoxic to human cancer cell lines GUMBUS and HL-60, with IC50 values between 42.7 and 149.4 µM. Neither had an effect on cell cycle. Only MSA induced apoptosis in HL-60 cells but not in GUMBUS cells, while tiopronin resulted in no apoptosis in either cell line. Combination studies of the MSA with hydrogen peroxide in living cells enhanced the production of reactive oxygen species in GUMBUS cells while tiopronin acted as antioxidant in HL-60 cells. MSA and tiopronin antagonized the cytotoxic effect of cisplatin, doxorubicin and methotrexate in combination studies. Our findings indicate that the antioxidant properties of both thiols prevail over their GPx inhibitory activity in human cancer cell lines.


Assuntos
Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Tiomalatos/farmacologia , Tiopronina/farmacologia , Animais , Antineoplásicos/administração & dosagem , Antioxidantes/administração & dosagem , Apoptose/efeitos dos fármacos , Bovinos , Linhagem Celular Tumoral , Glutationa Peroxidase/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Células HL-60 , Humanos , Concentração Inibidora 50 , Leucemia Promielocítica Aguda/tratamento farmacológico , Leucemia Promielocítica Aguda/patologia , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/patologia , Oxirredução/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Tiomalatos/administração & dosagem , Tiopronina/administração & dosagem
8.
Nitric Oxide ; 93: 25-33, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31541732

RESUMO

Leishmaniasis is a neglected tropical disease that demands for new therapeutic strategies due to adverse side effects and resistance development promoted by current drugs. Nitric oxide (NO)-donors show potential to kill Leishmania spp. but their use is limited because of their instability. In this work, we synthesize, characterize, and encapsulate S-nitroso-mercaptosuccinic acid into chitosan nanoparticles (NONPs) and investigate their activity on promastigotes and intracellular amastigotes of Leishmania (Leishmania) amazonensis. Cytotoxicity on macrophages was also evaluated. We verified that NONPs reduced both forms of the parasite in a single treatment. We also noticed reduction of parasitophorous vacuoles as an evidence of inhibition of parasite growth and resolution of infection. No substantial cytotoxicity was detected on macrophages. NONPs were able to provide a sustained parasite killing for both L. (L.) amazonensis infective stages with no toxicity on macrophages, representing a promising nanoplatform for cutaneous leishmaniasis.


Assuntos
Quitosana/química , Leishmania/efeitos dos fármacos , Nanopartículas/química , Doadores de Óxido Nítrico/farmacologia , Compostos Nitrosos/farmacologia , Tiomalatos/farmacologia , Animais , Quitosana/toxicidade , Cinética , Macrófagos/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Nanopartículas/toxicidade , Óxido Nítrico/química , Doadores de Óxido Nítrico/química , Doadores de Óxido Nítrico/toxicidade , Compostos Nitrosos/química , Compostos Nitrosos/toxicidade , Tiomalatos/química , Tiomalatos/toxicidade , Tripanossomicidas
9.
Talanta ; 204: 446-454, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31357319

RESUMO

A mercaptosuccinic acid functionalized hydrophilic magnetic metal-organic framework nanocomposite (denoted as mMOF@Au-MSA) was proposed and synthesized to provide an excellent platform for glycopeptide analysis. The novel nanomaterial integrated favorable advantages such as robust magnetic response from Fe3O4 magnetic nanoparticles, large surface area contributed by MOF, abundant ultra-high hydrophilic carboxylic groups from mercaptosuccinic acid, as well as unbiased affinity toward different types of glycopeptides. This nanocomposite was successfully utilized to capture glycopeptides from standard protein digests with the high selectivity and great sensitivity of 0.5 fmol µL-1. Notably, 307 glycopeptides assigned to 96 glycoproteins were identified from only 2 µL serum of breast cancer patient. The satisfying achievement indicated that the as-prepared nanopartical had promising potential in exploring the knowledge of glycoproteins in breast cancer.


Assuntos
Glicopeptídeos/sangue , Estruturas Metalorgânicas/química , Sequência de Aminoácidos , Neoplasias da Mama/sangue , Sequência de Carboidratos , Ouro/química , Humanos , Nanopartículas de Magnetita/química , Nanocompostos/química , Proteômica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Tiomalatos/química
10.
ACS Chem Biol ; 14(2): 266-275, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30645090

RESUMO

Leishmaniases affect the poorest people on earth and have no effective drug therapy. Here, we present the crystal structure of the mitochondrial isoform of class I fumarate hydratase (FH) from Leishmania major and compare it to the previously determined cytosolic Leishmania major isoform. We further describe the mechanism of action of the first class-specific FH inhibitor, 2-thiomalate, through X-ray crystallography and inhibition assays. Our crystal structures of both FH isoforms with inhibitor bound at 2.05 Å resolution and 1.60 Å resolution show high structural similarity. These structures further reveal that the selectivity of 2-thiomalate for class I FHs is due to direct coordination of the inhibitor to the unique Fe of the catalytic [4Fe-4S] cluster that is found in class I parasitic FHs but is absent from class II human FH. These studies provide the structural scaffold in order to exploit class I FHs as potential drug targets against leishmaniases as well as Chagas diseases, sleeping sickness, and malaria.


Assuntos
Fumarato Hidratase/química , Leishmania major/enzimologia , Tiomalatos/farmacologia , Domínio Catalítico , Cristalografia por Raios X , Fumarato Hidratase/efeitos dos fármacos , Estrutura Molecular
11.
Enzyme Microb Technol ; 120: 61-68, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30396400

RESUMO

Thiol dioxygenases are non-heme mononuclear-iron proteins and belong to the cupin superfamily. In 2014, mercaptosuccinate dioxygenase (Msdo) of Variovorax paradoxus B4 was identified as another bacterial cysteine dioxygenase (Cdo) homolog catalyzing the conversion of mercaptosuccinate (MS) into succinate and sulfite. To gain further insights into potentially important amino acid residues for enzyme activity, seven enzyme variants were generated and analyzed. (i) Three variants comprised the substitution of one conserved histidine residue each by leucine, either supposed to be mandatory for coordination of the Fe(II) cofactor (H93 and H95) or to be important for substrate positioning within the active site (H163). The corresponding enzyme variants were completely inactive confirming their essential roles for enzyme activity. (ii) Mutation C100S resulted as well in an inactive enzyme demonstrating its importance for either stability or activity of the protein. (iii) For eukaryotic Cdo, a hydrogen bond network for substrate positioning was postulated, and the corresponding amino acids are basically present in Msdo. Albeit the MsdoQ64A mutation exhibited an increased Km of 0.29 mM when compared to the wildtype with 0.06 mM, it did not significantly affect the specific activity. (iv) The variant MsdoR66A showed only very low activity even when high amounts of enzyme were applied indicating that this residue might be important for catalysis. (v) No strong effect had the mutation Y165F for which a specific enzyme activity of 10.22 µmol min-1 mg-1 protein and a Km value of 0.06 mM with high similarity to those of the wildtype enzyme were obtained. This residue corresponds to Y157 of human Cdo, which is part of the catalytic triad and is supposed to be involved in substrate positioning. Apparently, another residue could fulfill this role in Msdo, since the loss of Y165 did not have a strong effect.


Assuntos
Aminoácidos/química , Comamonadaceae/enzimologia , Cisteína Dioxigenase/metabolismo , Dioxigenases/metabolismo , Mutação , Tiomalatos/metabolismo , Sequência de Aminoácidos , Aminoácidos/genética , Catálise , Domínio Catalítico , Cisteína Dioxigenase/química , Cisteína Dioxigenase/genética , Dioxigenases/química , Dioxigenases/genética , Mutagênese Sítio-Dirigida , Homologia de Sequência , Especificidade por Substrato
12.
Mater Sci Eng C Mater Biol Appl ; 92: 61-68, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30184787

RESUMO

Aggregation-induced emission (AIE) should be the most interest fluorescent phenomenon over the past few decades. The luminescence polymeric nanoparticles (LPNs) with AIE characteristic have attracted great research attention for biological imaging and many other biomedical applications owing to their good biocompatibility and negative toxicity. However, the preparation of LPNs with desirable optical properties using traditional organic dyes still remains a great challenge for the aggregation-caused quenching (ACQ) effect and aggregation of hydrophobic dyes in the core of LPNs. In this work, we reported a novel and simple method for fabrication of biodegradable AIE-active LPNs via the combination of condensation and click reactions. For preparation of these AIE-active LPNs, the thiol groups-containing hydrophilic copolymers (PEG-MA) were first synthesized through the condensation reaction between polyethylene glycol and mercaptosuccinic acid. The PEG-MA copolymers were further reacted with AIE dye PhE-OE through a catalyst-free thiol-yne click reaction. These obtained PEG-MA-PhE LPNs were fully characterized by a number of characterization techniques. All the results confirmed that PEG-MA-PhE LPNs possess excellent compatibility, intense red luminescence, great photostability and high water dispersibility. These features make PEG-MA-PhE LPNs promising candidates for various biomedical applications.


Assuntos
Alcinos/química , Polímeros/química , Compostos de Sulfidrila/química , Células A549 , Catálise , Sobrevivência Celular/efeitos dos fármacos , Química Click , Corantes Fluorescentes/química , Humanos , Microscopia Confocal , Nanopartículas/química , Nanopartículas/toxicidade , Polietilenoglicóis/química , Polímeros/síntese química , Polímeros/farmacologia , Tiomalatos/química
13.
Mol Neurobiol ; 55(10): 7619-7634, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29430618

RESUMO

Recent studies have shown that probucol (PB), a hipocholesterolemic agent with antioxidant and anti-inflammatory properties, presents neuroprotective properties. On the other hand, adverse effects have limited PB's clinical application. Thus, the search for PB derivatives with no or less adverse effects has been a topic of research. In this study, we present a novel organoselenium PB derivative (RC513) and investigate its potential protective activity in an in vitro experimental model of oxidative toxicity induced by tert-butyl hydroperoxide (tBuOOH) in HT22 neuronal cells, as well as exploit potential protective mechanisms. tBuOOH exposure caused a significant decrease in the cell viability, which was preceded by (i) increased reactive species generation and (ii) decreased mitochondrial maximum oxygen consumption rate. RC513 pretreatment (48 h) significantly prevented the tBuOOH-induced decrease of cell viability, RS generation, and mitochondrial dysfunction. Of note, RC513 significantly increased glutathione peroxidase (GPx) activity and mRNA expression of GPx1, a key enzyme involved in peroxide detoxification. The use of mercaptosuccinic acid, an inhibitor of GPx, significantly decreased the protective activity of RC513 against tBuOOH-induced cytotoxicity in HT22 cells, highlighting the importance of GPx upregulation in the observed protection. In summary, the results showed a significant protective activity of a novel PB derivative against tBuOOH-induced oxidative stress and mitochondrial dysfunction, which was related to the upregulation of GPx. Our results point to RC513 as a promising neuroprotective molecule, even though studies concerning potential beneficial effects and safety aspects of RC513 under in vivo conditions are well warranted.


Assuntos
Desenho de Fármacos , Glutationa Peroxidase/metabolismo , Neurônios/enzimologia , Fármacos Neuroprotetores/síntese química , Fármacos Neuroprotetores/farmacologia , Probucol/síntese química , Probucol/farmacologia , Regulação para Cima , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Glutationa Peroxidase/genética , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Neurônios/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Compostos de Sulfidrila/metabolismo , Tiomalatos , Fatores de Tempo , terc-Butil Hidroperóxido , Glutationa Peroxidase GPX1
14.
J Biol Chem ; 293(16): 5878-5894, 2018 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-29449371

RESUMO

Plasmodium falciparum (Pf), the causative agent of malaria, has an iron-sulfur cluster-containing class I fumarate hydratase (FH) that catalyzes the interconversion of fumarate to malate, a well-known reaction in the tricarboxylic acid cycle. In humans, the same reaction is catalyzed by class II FH that has no sequence or structural homology with the class I enzyme from Plasmodium Fumarate is generated in large quantities in the parasite as a by-product of AMP synthesis and is converted to malate by FH and then used in the generation of the key metabolites oxaloacetate, aspartate, and pyruvate. Previous studies have identified the FH reaction as being essential to P. falciparum, but biochemical characterization of PfFH that may provide leads for the development of specific inhibitors is lacking. Here, we report on the kinetic characterization of purified recombinant PfFH, functional complementation of fh deficiency in Escherichia coli, and mitochondrial localization in the parasite. We found that the substrate analog mercaptosuccinic acid is a potent PfFH inhibitor, with a Ki value in the nanomolar range. The fh gene could not be knocked out in Plasmodium berghei when transfectants were introduced into BALB/c mice; however, fh knockout was successful when C57BL/6 mice were used as host, suggesting that the essentiality of the fh gene to the parasite was mouse strain-dependent.


Assuntos
Fumarato Hidratase/metabolismo , Malária/parasitologia , Plasmodium berghei/enzimologia , Plasmodium falciparum/enzimologia , Animais , Fumarato Hidratase/análise , Fumarato Hidratase/genética , Fumaratos/metabolismo , Técnicas de Inativação de Genes , Genes Essenciais , Humanos , Malatos/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Ácido Oxaloacético/metabolismo , Plasmodium berghei/genética , Plasmodium berghei/crescimento & desenvolvimento , Plasmodium berghei/metabolismo , Plasmodium falciparum/genética , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium falciparum/metabolismo , Especificidade por Substrato , Tiomalatos/metabolismo
15.
J Mater Chem B ; 6(24): 4071-4081, 2018 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31372219

RESUMO

Crosslinked polyesters with Young's moduli similar to that of certain soft biological tissues were prepared via bulk polycondensation of thiomalic acid and 1,8-octanediol alone, and with citric or maleic acid. The copolymers were converted to nitric oxide (NO)-releasing S-nitrosothiol (RSNO) analogues by reaction with tert-butyl nitrite. Additional conjugation steps were avoided by inclusion of the thiolated monomer during the polycondensation to permit thiol conversion to RSNOs. NO release at physiological pH and temperature (pH 7.4, 37 °C) was determined by chemiluminescence-based NO detection. The average total NO content for poly(thiomalic-co-maleic acid-co-1,8-octanediol), poly(thiomalic-co-citric acid-co-1,8-octanediol), and poly(thiomalic acid-co-1,8-octanediol) was 130 ± 39 µmol g-1, 200 ± 35 µmol g-1, and 130 ± 11 µmol g-1, respectively. The antibacterial properties of the S-nitrosated analogues were confirmed against Escherichia coli and Staphylococcus aureus. The hydrolytic degradation products were analyzed by time-of-flight mass spectrometry after a 10-week study to investigate their composition. Tensile mechanical tests were performed on the non-nitrosated polymers as well as their S-nitrosated derivatives and suggested that the materials have appropriate Young's moduli and elongation values for biomedical applications.


Assuntos
Antibacterianos/farmacologia , Doadores de Óxido Nítrico/farmacologia , Óxido Nítrico/química , Poliésteres/farmacologia , S-Nitrosotióis/química , Tiomalatos/química , Antibacterianos/síntese química , Plásticos Biodegradáveis/síntese química , Plásticos Biodegradáveis/farmacologia , Ácido Cítrico/química , Módulo de Elasticidade , Escherichia coli/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Maleatos/química , Doadores de Óxido Nítrico/síntese química , Octanóis/química , Poliésteres/síntese química , Polimerização , Staphylococcus aureus/efeitos dos fármacos , Temperatura
16.
Colloids Surf B Biointerfaces ; 160: 220-227, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-28942156

RESUMO

Although antibacterial activities of graphene oxide (GO) and its derivatives have been investigated comprehensively, their antifungal properties are still less reported. Yet, fungal contamination seriously threatens the public health. Herein, we present a design of graphene oxide-borneol (GOB) composite, and report its great antifungal effect. This GOB composite is prepared by esterification of borneol with thiomalic-acid-modified GO sheets, where the linker molecule is used to increase surface carboxyl groups. As a result, the antifungal activity displays a dramatically conversion from no activity of GO and its derivatives to distinct antifungal adhesion and growth inhibition of the GOB. Under microscopy, few spores can be found on the GOB surface, while large numbers of sporangia and spores adhere and grow on the control groups. It is also worth noting that on the GOB sample the fallen spore does not germinate even after 5days, demonstrating a long-term antifungal effect of the GOB composite. Further studies confirm that carbon stereochemistry rather than wettability plays a crucial role on the antifungal adhesion properties. This study not only highlights a promising GOB composite as a candidate of graphene-based antifungal agent, but also provides us with in-depth understanding of the interactions between fungi and graphene-based materials.


Assuntos
Antifúngicos/farmacologia , Canfanos/química , Grafite/química , Mucor/efeitos dos fármacos , Esporos Fúngicos/efeitos dos fármacos , Tiomalatos/química , Animais , Antifúngicos/síntese química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Camundongos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Mucor/crescimento & desenvolvimento , Óxidos/química , Especificidade da Espécie , Esporos Fúngicos/crescimento & desenvolvimento , Propriedades de Superfície
17.
Int J Pharm ; 530(1-2): 401-414, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28779982

RESUMO

Thiolated cationic pullulan was synthesized by conjugating pullulan with polyethyleneimine (PEI) and mercaptosuccinic acid (MSA). The formed conjugate was oxidized to obtain disulfide linked cationic pullulan (PPMSS). PPMSS exhibited good buffering capacity and nanoplexes formulated were of size less than 150nm. Nanoplexes formed with PPMSS are redox sensitive and susceptible to reductive cleavage by dithiothreitol (DTT) ensuring the intracellular release of DNA. In vitro, cytotoxic evaluation studies of polymers in C6 cell lines established its non-toxic nature. The studies using endocytosis inhibitors revealed the uptake pathways of nanoplexes. Further, the plasmid and polymer tracking studies indicated the successful unpacking of DNA from the nanoplexes and its nuclear localization. The gene transfection efficiency was established by the p53 gene expression studies. Furthermore, the ability of the polymer to inhibit efflux pumping in cancer cells has also been elucidated in terms of P-gp inhibition studies and drug retention kinetics using the anticancer drug, doxorubicin (DOX). Our results also suggest that greater retention of DOX was accompanied by the reduction of disulfide linkage by a ubiquitous intracellular stimulus, glutathione. Thus simultaneous gene and drug delivery using redox sensitive cationic polymers may have a promising potential in cancer therapy.


Assuntos
Sistemas de Liberação de Medicamentos , Glioma/genética , Glucanos/química , Transfecção , Animais , Linhagem Celular Tumoral , Doxorrubicina/administração & dosagem , Glioma/terapia , Camundongos , Oxirredução , Polietilenoimina/química , Ratos , Tiomalatos/química
18.
PLoS One ; 12(3): e0174256, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28358882

RESUMO

2-Mercaptosuccinate (MS) and 3,3´-ditiodipropionate (DTDP) were discussed as precursor substance for production of polythioesters (PTE). Therefore, degradation of MS and DTDP was investigated in Advenella mimigardefordensis strain DPN7T, applying differential proteomic analysis, gene deletion and enzyme assays. Protein extracts of cells cultivated with MS, DTDP or 3-sulfinopropionic acid (SP) were compared with those cultivated with propionate (P) and/or succinate (S). The chaperone DnaK (ratio DTDP/P 9.2, 3SP/P 4.0, MS/S 6.1, DTDP/S 6.2) and a Do-like serine protease (DegP) were increased during utilization of all organic sulfur compounds. Furthermore, a putative bacterioferritin (locus tag MIM_c12960) showed high abundance (ratio DTDP/P 5.3, 3SP/P 3.2, MS/S 4.8, DTDP/S 3.9) and is probably involved in a thiol-specific stress response. The deletion of two genes encoding transcriptional regulators (LysR (MIM_c31370) and Xre (MIM_c31360)) in the close proximity of the relevant genes of DTDP catabolism (acdA, mdo and the genes encoding the enzymes of the methylcitric acid cycle; prpC,acnD, prpF and prpB) showed that these two regulators are essential for growth of A. mimigardefordensis strain DPN7T with DTDP and that they most probably regulate transcription of genes mandatory for this catabolic pathway. Furthermore, proteome analysis revealed a high abundance (ratio MS/S 10.9) of a hypothetical cupin-2-domain containing protein (MIM_c37420). This protein shows an amino acid sequence similarity of 60% to a newly identified MS dioxygenase from Variovorax paradoxus strain B4. Deletion of the gene and the adjacently located transcriptional regulator LysR, as well as heterologous expression of MIM_c37420, the putative mercaptosuccinate dioxygenase (Msdo) from A. mimigardefordensis, showed that this protein is the key enzyme of MS degradation in A. mimigardefordensis strain DPN7T (KM 0.2 mM, specific activity 17.1 µmol mg-1 min-1) and is controlled by LysR (MIM_c37410).


Assuntos
Alcaligenaceae/metabolismo , Compostos Orgânicos/metabolismo , Proteômica/métodos , Eletroforese em Gel Bidimensional , Espectrometria de Massas , Propionatos/metabolismo , Proteoma/metabolismo , Software , Tiomalatos/metabolismo
19.
Nitric Oxide ; 61: 10-19, 2016 12 30.
Artigo em Inglês | MEDLINE | ID: mdl-27693703

RESUMO

Nitric oxide (NO) is a signaling molecule involved in plant response to various abiotic stresses. However, the application of NO donors in agriculture is hampered by the instability of these compounds. Despite the successful uses of NO-releasing nanoparticles for biomedical purposes and the variety of nanomaterials developed as carrier systems of agrochemicals, the potential applications of nanocarriers for NO delivery in plants have not yet been tested. Herein, we report the synthesis and characterization of chitosan nanoparticles (CS NPs) containing the NO donor S-nitroso-mercaptosuccinic acid (S-nitroso-MSA). The efficiency of these NO-releasing NPs in mitigating the deleterious effects of salinity on maize plants was compared to that of the non-encapsulated NO donor. The NPs were synthesized through ionotropic gelation process, and mercaptosuccinic acid (MSA), the NO donor precursor, was encapsulated into CS NPs (91.07% encapsulation efficiency). Free thiol groups of MSA-CS NPs were nitrosated, leading to S-nitroso-MSA-CS NPs (NO-releasing NPs). The incorporation of S-nitroso-MSA into CS NPs allowed a sustained NO release. Treatments of salt-stressed maize plants with S-nitroso-MSA-CS NPs resulted in a higher leaf S-nitrosothiols content compared to that of free S-nitroso-MSA. Moreover, S-nitroso-MSA-CS NPs were more efficient than was the free NO donor in the amelioration of the deleterious effects of salinity in photosystem II activity, chlorophyll content and growth of maize plants because the protective action of the nanoencapsulated S-nitroso-MSA was achieved at lower dosages. Overall, these results demonstrate the positive impact of S-nitroso-MSA nanoencapsulation in increasing NO bioactivity in maize plants under salt stress.


Assuntos
Quitosana/química , Nanopartículas/química , Óxido Nítrico/química , Tolerância ao Sal/efeitos dos fármacos , Cloreto de Sódio/efeitos adversos , Zea mays/efeitos dos fármacos , Biotecnologia , Nanotecnologia , Óxido Nítrico/farmacocinética , Óxido Nítrico/farmacologia , Tiomalatos/química
20.
J Nanosci Nanotechnol ; 16(1): 840-3, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27398533

RESUMO

A colorimetric assay has been developed for detection of Cd²âº utilizing DL-mercaptosuccinic acid-modified gold nanoparticles (MSA-AuNPs). The method showed good selectivity for Cd²âº over other metal ions. As a result, the linear relationships (r > 0.9606) between concentration 0.07 mM and 0.20 mM for cadmium ion were obtained. The detection limit was as low as 0.07 mM by the naked eye. The effect of pH on the aggregation was optimized. The MSA-AuNPs probe could be used to detect Cd²âº in an aqueous solution based on the aggregation-induced color change of MSA-AuNPs.


Assuntos
Cádmio/análise , Ouro/química , Nanopartículas Metálicas/química , Tiomalatos/química , Íons/análise
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