RESUMO
Acanthamoeba are free living amoeba that have been isolated from different environments like soil, water, air dust. Moreover, they are also able to act as opportunist pathogens, mainly causing a fatal encephalitis and also keratitis in both human and animals. This study was aimed to evaluate the activity of the Medicines for Malaria Venture (MMV) compounds against the trophozoite stage of Acanthamoeba castellanii Neff. Sixteen compounds showed ≥90% inhibition of parasite growth in the initial screen (10⯵M). Those set were further evaluated to determine the inhibitor concentration that inhibit the 50% of the initial population and cytotoxicity against murine macrophages. Among the compounds included in the pathogen box, pentamidine and posaconazole were the most effective against this parasite with an of IC50 of 0.567⯱â¯0.04 and 0.630⯱â¯0.11, respectively.
Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Amebicidas/farmacologia , Amebicidas/classificação , Animais , Linhagem Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Concentração Inibidora 50 , Camundongos , Pentamidina/farmacologia , Triazóis/farmacologia , Trofozoítos/efeitos dos fármacosRESUMO
Bioassay-guided fractionation of the antikinetoplastid extract of the brown alga Dictyota spiralis has led to the isolation of spiralyde A (1), a new dolabellane aldehyde, along with other five known related diterpenes (2â»6). Their structures were determined by HRESIMS, 1D and 2D NMR spectroscopy, and comparison with data reported in the literature. The antiparasitic activity of all compounds was evaluated. Spiralyde A (1) and the known compound 3,4-epoxy-7,18-dolabelladiene (2) were the most active compounds against Leishmania amazonensis and Trypanosoma cruzi. Spiralyde A (1) was the most potent compound, comparable to benznidazole, the reference drug for trypanocidal activity.
Assuntos
Diterpenos/química , Phaeophyceae/química , Fracionamento Químico , Diterpenos/isolamento & purificação , Diterpenos/farmacologia , Leishmania/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Trypanosoma cruzi/efeitos dos fármacosRESUMO
In this work, the presence of free-living amoebae (FLA) in dishcloths collected from human activity related places was evaluated. Once in the laboratory, 6 cm2 pieces of each dishcloth were cut and washed with Page's Amoeba Solution (PAS) in sterile tubes. After washing, the dishcloth pieces were removed, and the tubes were centrifuged (1500 rpm for 10 min). The obtained pellets were seeded onto 2% non-nutrient agar (NNA) plates, incubated at room temperature and were monitored daily an inverted microscope. Once clonal cultures were obtained (only one type of FLA observed), molecular analyses were carried out in order to characterize the isolated FLA strains at the genus/genotype level. From the 31 dishcloths which were processed, FLA strains were isolated in NNA plates in 13 the samples (13/31, 42%). However, and due to bacterial overgrowth, only six strains were characterized at the molecular level (PCR and sequencing). Among the PCR positive strains, 83.33% (5/6) of the PCR positive samples belonged to Acanthamoeba genus (80% (4/5) to genotype T4 and 20% (1/5) to genotype T11). Furthermore, one strain was identified as a member of Allovahlkampfia genus using both morphological and molecular approaches. To the best of our knowledge, this is the first report on the isolation of Allovahlkampfia genus from dishcloths and in the Spanish territory. The presence of FLA in dishcloths should raise awareness to improve hygienic strategies in food- and domestic-related environments, in order to prevent contamination with these protozoa, which are able to be pathogenic and even to act as vehicles of other pathogenic agents.
Assuntos
Acanthamoeba/classificação , Acanthamoeba/isolamento & purificação , Amoeba/classificação , Amoeba/isolamento & purificação , Manipulação de Alimentos/métodos , Genótipo , Humanos , Reação em Cadeia da Polimerase , EspanhaRESUMO
The lack of an effective chemotherapy for treatment of protozoan disease urges a wide investigation for active compounds, and plant-derived compounds continue to provide key leads for therapeutic agents. The current study reports the in vitro antiprotozoal evaluation of the Algerian medicinal plant Pulicaria inuloides against Leishmania amazonensis, Trypanosoma cruzi, and Acanthamoeba castellanii str. Neff. All the extracts from the aerial part showed to be present a higher leishmanicidal activity than anti-Acanthamoeba or Trypanosoma. Therefore, bioguided fractionation of the active CHCl3 extract led to the isolation and characterization of the flavonol, quercetagetin-3,5,7,3'-tetramethyl ether (1) as the main component. The structure of compound 1 was established by extensive 1D and 2D NMR spectroscopic analysis (COSY, HSQC, HMBC, and ROESY experiments), chemical transformation (derivatives 2 and 3), and comparison with data in the literature. Compound 1 and derivatives 2 and 3 were further evaluated against the promastigote and amastigote stage of L. amazonensis. Compounds 1-3 exhibited moderate leishmanicidal activity with IC50 values ranging from 0.234 to 0.484 mM and from 0.006 to 0.017 mM for the promastigote and amastigote forms, respectively, as well as low toxicity levels on macrophages (CC50 ranging from 0.365 to 0.664 mM). This study represents the first report of the antiprotozoal evaluation of Pulicaria inuloides, and the results highlight this species as a promising source of leishmanicidal agents.
Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Flavonoides/farmacologia , Leishmania mexicana/efeitos dos fármacos , Extratos Vegetais/farmacologia , Pulicaria/metabolismo , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Argélia , Animais , Fracionamento Químico , Flavonoides/química , Extratos Vegetais/química , Plantas Medicinais/metabolismo , Tripanossomicidas/químicaRESUMO
In order to promote a local Tunisian product, this study was designed to examine, for the first time, the anti-Acanthamoeba activity (Acanthamoeba castellanii Neff) of the essential oils of Tunisian Citrus sinensis peels (Maltese half-blood) and the effect of viroid plant infection on this activity. To do so, three samples of peels' essential oils were studied: from a healthy plant (Control), a plant inoculated with Citrus exocortis viroid (CEVd) and one inoculated with hot stunt cachexia viroid (HSVd). The samples were extracted by hydrodistillation from dried peels and characterized by GC-MS. Limonene was the major component with a percentage ranging from 90.76 to 93.34% for (CEVd) sample and (Control), respectively. Anti-Acanthamoeba activity of the tested oils was determined by the Alamar Blue® assay. Primary results showed a strong potential anti-Acanthamoeba activity with an IC50 ranging from 36.6 to 54.58 µg/ml for (HSVd) and (CEVd) samples, respectively. In terms of the effect of viroid infection, a strong positive correlation was observed between different chemical classes and anti-Acanthamoeba activity.
Assuntos
Acanthamoeba castellanii/efeitos dos fármacos , Amebicidas/farmacologia , Citrus sinensis/química , Óleos de Plantas/farmacologia , Viroides/fisiologia , Acanthamoeba castellanii/crescimento & desenvolvimento , Amebicidas/química , Amebicidas/isolamento & purificação , Citrus sinensis/virologia , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Concentração Inibidora 50 , Monoterpenos/química , Monoterpenos/isolamento & purificação , Monoterpenos/farmacologia , Óleos de Plantas/química , Óleos de Plantas/isolamento & purificação , Análise de Regressão , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Trofozoítos/efeitos dos fármacosRESUMO
Efficient treatments against Acanthamoeba Keratitis (AK), remains until the moment, as an issue to be solved due to the existence of a cyst stage which is highly resistant to most chemical and physical agents. In this study, two antiglaucoma eye drops were tested for their activity against Acanthamoeba. Moreover, this study was based on previous data which gave us evidence of a possible link between the absences of Acanthamoeba at the ocular surface in patients treated with beta blockers for high eye pressure both containing timolol as active principle. The amoebicidal activity of the tested eye drops was evaluated against four strains of Acanthamoeba using Alamar blue method. For the most active drug the cysticidal activity against A. castellanii Neff cysts and further experiments studying changes in chromatin condensation levels, in the permeability of the plasmatic membrane, the mitochondrial membrane potential and the ATP levels in the treated amoebic strains were done. Even though both eye drops were active against the different tested strains of Acanthamoeba, statistical analysis revealed that one of them (Timolol Sandoz) was the most effective one against all the tested strains presenting IC50s ranging from 0.529% ± 0.206 for the CLC 16 strain to 3.962% ± 0.150 for the type strain Acanthamoeba castellanii Neff. Timolol Sandoz 0.50% seems to induce amoebic cell death by damaging the amoebae at the mitochondrial level. Considering its effect, Timolol Sandoz 0.50% could be used in the case of contact lens wearers and patients with glaucoma.
Assuntos
Ceratite por Acanthamoeba/prevenção & controle , Acanthamoeba/efeitos dos fármacos , Agonistas de Receptores Adrenérgicos alfa 2/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Glaucoma/tratamento farmacológico , Pressão Intraocular/efeitos dos fármacos , Ceratite por Acanthamoeba/tratamento farmacológico , Agonistas de Receptores Adrenérgicos alfa 2/administração & dosagem , Agonistas de Receptores Adrenérgicos alfa 2/uso terapêutico , Antagonistas Adrenérgicos beta/administração & dosagem , Antagonistas Adrenérgicos beta/uso terapêutico , Análise de Variância , Apoptose/efeitos dos fármacos , Tartarato de Brimonidina/administração & dosagem , Tartarato de Brimonidina/farmacologia , Tartarato de Brimonidina/uso terapêutico , Combinação Tartarato de Brimonidina e Maleato de Timolol/administração & dosagem , Combinação Tartarato de Brimonidina e Maleato de Timolol/farmacologia , Combinação Tartarato de Brimonidina e Maleato de Timolol/uso terapêutico , Concentração Inibidora 50 , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Soluções Oftálmicas , Timolol/administração & dosagem , Timolol/farmacologia , Timolol/uso terapêuticoRESUMO
Free-living amoebae of genus Acanthamoeba are opportunistic pathogens widely distributed in the environment, and are the causative agents of several humans' infections, such as Acanthamoeba keratitis, Granulomatous Amoebic Encephalitis and also disseminated infections. The existence of the cyst stage complicates Acanthamoeba therapy as it is highly resistant to antibiotics and physical agents. All these facts reinforced the necessity to find and develop an effective therapy against Acanthamoeba infections. In the present study, we are interested to several seaweeds species collected from the Tunisian coasts and belonging to the 3 phyla (brown, green and red algae). The aim was to quantify the Total Phenolic Compounds in different organic extract, to evaluate antioxidant capacity (DPPH and ABTS) and to study the antiprotozoal activity against A. castellanii Neff. The parasites have been inhibited by all extracts with an IC50 ranged from 52,3±1.8 µg/mL for ethyl acetate extract, to 134,6±0.7 µg/mL for the hexanic one for the various species studied.
Assuntos
Amebicidas/farmacologia , Antioxidantes/farmacologia , Phaeophyceae/fisiologia , Rodófitas/fisiologia , Ulva/fisiologia , Acanthamoeba castellanii/efeitos dos fármacos , Amebicidas/isolamento & purificação , Antioxidantes/isolamento & purificação , Relação Dose-Resposta a Droga , Sequestradores de Radicais Livres/isolamento & purificação , Sequestradores de Radicais Livres/farmacologia , Concentração Inibidora 50 , Mar Mediterrâneo , Phaeophyceae/química , Fenóis/isolamento & purificação , Fenóis/farmacologia , Rodófitas/química , Solventes , Tunísia , Ulva/químicaRESUMO
Free-living amoebae (FLA) are protozoa that are widely distributed in the environment mainly in water and soil related habitats. These amoebae have also been reported to be associated with some bacterial pathogens for humans such as Campylobacter spp. The species C. jejuni is the causative agent of about 90% of human campylobacteriosis cases worldwide and this disease may even end up in severe autoimmune sequelae as Guillain-Barré syndrome (GBS). In this study, the interactions between the strain Acanthamoeba castellanii Neff and Campylobacter jejuni was investigated. Campylobacter jejuni was coincubated with Acanthamoeba castellanii Neff trophozoites at different temperatures, in order to evaluate the C. jejuni ability to grow in presence A. castellanii culture and Acanthamoeba Conditioned Medium (ACM). C. jejuni was coincubated with A. castellanii axenic culture at different temperatures in aerobic conditions. Our results revealed that bacteria were still cultivable (Blood Agar medium, at 37 °C, in microaerophilic atmosphere) after a 14 days C. jejuni - A. castellanii coculture, comparing with C. jejuni alone, which was only cultivable for 24 h.
Assuntos
Acanthamoeba castellanii/fisiologia , Campylobacter jejuni/crescimento & desenvolvimento , Acanthamoeba castellanii/efeitos dos fármacos , Acanthamoeba castellanii/crescimento & desenvolvimento , Aerobiose , Animais , Antibacterianos/farmacologia , Campylobacter jejuni/efeitos dos fármacos , Campylobacter jejuni/fisiologia , Técnicas de Cocultura , Gentamicinas/farmacologia , Humanos , TemperaturaRESUMO
Free-living amoebae (FLA) are opportunistic protozoa widely distributed in the environment. They are frequently found in water and soil samples, but they have also been reported to be associated with bacterial human pathogens such as Legionella spp. Campylobacter spp or Vibrio cholerae among others. Including within Vibrio spp. V. harveyi (Johnson and Shunk, 1936) is a bioluminescent marine bacteria which has been found swimming freely in tropical marine waters, being part of the stomach and intestine microflora of marine animals, and as both a primary and opportunistic pathogen of marine animals. Our aim was to study the interactions between Vibrio harveyi and Acanthamoeba castellanii Neff. Firstly, in order to analyze changes in it cultivability, V. harveyi was coincubated with A. castellanii Neff axenic culture and with Acanthamoeba Conditioned Medium (ACM) at different temperatures in aerobic conditions. Interestingly, at 4 °C and 18-20 °C bacteria were still cultivable in marine agar, at 28 °C, in aerobic conditions, but there weren't significant differences comparing with the controls. We also noted an enhanced migration of Acanthamoeba toward V. harveyi on non-nutrient agar plates compared to controls with no bacteria.
Assuntos
Acanthamoeba castellanii/fisiologia , Vibrio/fisiologia , Acanthamoeba castellanii/crescimento & desenvolvimento , Antibacterianos/farmacologia , Aquicultura , Técnicas de Cocultura , Testes de Sensibilidade Microbiana , Movimento , Vibrio/efeitos dos fármacos , Vibrio/crescimento & desenvolvimentoRESUMO
BACKGROUND: The in vitro activity of the brown seaweed Dictyota spiralis against both Leishmania amazonensis and Trypanosoma cruzi was evaluated in a previous study. Processing by bio-guided fractionation resulted in the isolation of three active compounds, classified as diterpenes. In the present study, we performed several assays to detect clinical features associated to cell death in L. amazonensis and T. cruzi with the aim to elucidate the mechanism of action of these compounds on parasitic cells. METHODS: The aims of the experiments were to detect and evaluate specific events involved in apoptosis-like cell death in the kinetoplastid, including DNA condensation, accumulation of reactive oxygen species and changes in ATP concentration, cell permeability and mitochondrial membrane potential, respectively, in treated cells. RESULTS: The results demonstrated that the three isolated diterpenes could inhibit the tested parasites by inducing an apoptosis-like cell death. CONCLUSIONS: These results encourage further investigation on the isolated compounds as potential drug candidates against both L. amazonensis and T. cruzi.
Assuntos
Antiprotozoários/farmacologia , Apoptose/efeitos dos fármacos , Leishmania/efeitos dos fármacos , Phaeophyceae/química , Extratos Vegetais/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Antiprotozoários/química , Morte Celular/efeitos dos fármacos , Diterpenos/química , Diterpenos/farmacologia , Leishmania/citologia , Leishmania/metabolismo , Extratos Vegetais/química , Espécies Reativas de Oxigênio/metabolismo , Trypanosoma cruzi/citologia , Trypanosoma cruzi/metabolismoRESUMO
The validation of anti-Acanthamoeba activity of commercial eye drops has gained a great interest recently and a growing number of commercials eye drop were evaluated for their aptitude to inhibit Acanthamoeba as a second pharmacological effect. In the present study, three different eye drops, commercializing in Spain, including TobraDex, Cusimolol and Colircusi antiedema have been tested in vitro against trophozoites and cysts stage of the facultative pathogen Acanthamoeba. The alamarBlue™ method was used to evaluate both trophocidal and cysticidal properties. The most active eye drops were tested for their impact on some programmed cell death features. We found out that the cells inhibition was strain and eye drop dependent, and 5% eye drop was able to eliminate both trophozoite and cyst stage of Acanthamoeba spp. A treatment of 24 h with 5% of TobraDex or Cusimolol was able to show DNA condensation, collapse in the mitochondrial membrane potential and reduction of the ATP level production in Acanthamoeba. We could assume that the present eye drops could induce programed cell death like process in Acanthamoeba via mitochondrial pathway.
Assuntos
Acanthamoeba , Amebicidas , Soluções Oftálmicas , Acanthamoeba/efeitos dos fármacos , Amebicidas/farmacologia , Amebicidas/uso terapêutico , Soluções Oftálmicas/farmacologia , Soluções Oftálmicas/uso terapêutico , TrofozoítosRESUMO
Primary amoebic encephalitis (PAM) is a lethal disease caused by the opportunistic pathogen, Naegleria fowleri. This amoebic species is able to live freely in warm aquatic habitats and to infect children and young adults when they perform risk activities in these water bodies such as swimming or splashing. Besides the need to increase awareness of PAM which will allow an early diagnosis, the development of fully effective therapeutic agents is needed. Current treatment options are amphotericin B and miltefosine which are not fully effective and also present toxicity issues. In this study, the in vitro activity of various sesquiterpenes isolated from the red alga Laurencia johnstonii were tested against the trophozoite stage of a strain of Naegleria fowleri. Moreover, the induced effects (apoptotic cell death) of the most active compound, laurinterol (1), was evaluated by measuring DNA condensation, damages at the mitochondrial level, cell membrane disruption and production of reactive oxygen species (ROS). The obtained results demonstrated that laurinterol was able to eliminate the amoebae at concentrations of 13.42 ± 2.57 µM and also to induced programmed cell death (PCD) in the treated amoebae. Moreover, since ATP levels were highly affected and laurinterol has been previously reported as an inhibitor of the Na+/K+-ATPase sodium-potassium ion pump, comparison with known inhibitors of ATPases were carried out. Our results points out that laurinterol was able to inhibit ENA ATPase pump at concentrations 100 times lower than furosemide.
Assuntos
Antiparasitários/farmacologia , Infecções Protozoárias do Sistema Nervoso Central/tratamento farmacológico , Naegleria fowleri/fisiologia , Proteínas de Protozoários/antagonistas & inibidores , Sesquiterpenos/farmacologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Trofozoítos/efeitos dos fármacos , Trifosfato de Adenosina/metabolismo , Anfotericina B/uso terapêutico , Antiparasitários/metabolismo , Apoptose/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Humanos , Laurencia/metabolismo , Fosforilcolina/análogos & derivados , Fosforilcolina/uso terapêutico , Espécies Reativas de Oxigênio/metabolismo , Sesquiterpenos/metabolismo , Trofozoítos/fisiologiaRESUMO
Thiomonas bacteria are ubiquitous at acid mine drainage sites and play key roles in the remediation of water at these locations by oxidizing arsenite to arsenate, favouring the sorption of arsenic by iron oxides and their coprecipitation. Understanding the adaptive capacities of these bacteria is crucial to revealing how they persist and remain active in such extreme conditions. Interestingly, it was previously observed that after exposure to arsenite, when grown in a biofilm, some strains of Thiomonas bacteria develop variants that are more resistant to arsenic. Here, we identified the mechanisms involved in the emergence of such variants in biofilms. We found that the percentage of variants generated increased in the presence of high concentrations of arsenite (5.33 mM), especially in the detached cells after growth under biofilm-forming conditions. Analysis of gene expression in the parent strain CB2 revealed that genes involved in DNA repair were upregulated in the conditions where variants were observed. Finally, we assessed the phenotypes and genomes of the subsequent variants generated to evaluate the number of mutations compared to the parent strain. We determined that multiple point mutations accumulated after exposure to arsenite when cells were grown under biofilm conditions. Some of these mutations were found in what is referred to as ICE19, a genomic island (GI) carrying arsenic-resistance genes, also harbouring characteristics of an integrative and conjugative element (ICE). The mutations likely favoured the excision and duplication of this GI. This research aids in understanding how Thiomonas bacteria adapt to highly toxic environments, and, more generally, provides a window to bacterial genome evolution in extreme environments.
Assuntos
Arsenitos/metabolismo , Biofilmes/crescimento & desenvolvimento , Burkholderiales , Genoma Bacteriano/genética , Adaptação Fisiológica/genética , Arseniatos/metabolismo , Arsênio/metabolismo , Burkholderiales/genética , Burkholderiales/crescimento & desenvolvimento , Burkholderiales/metabolismo , Reparo do DNA/genética , Elementos de DNA Transponíveis/genética , Evolução Molecular , Perfilação da Expressão Gênica , Variação Genética/genética , Ilhas Genômicas/genética , Mineração , Sequenciamento Completo do GenomaRESUMO
Free living, cosmopolitan amoebae from Acanthamoeba genus present a serious risk to human health. As facultative human parasites, these amoebae may cause Acanthamoeba keratitis (AK). Acanthamoeba keratitis is a severe, vision-threatening corneal infection with non-specific symptoms. The number of reported AK cases worldwide has been increasing every year. Moreover, 90% of Acanthamoeba keratitis cases are related to contact lens use. Wearing and storage contact lenses not in accordance with the physicians and manufacturers recommendations are the primary key risk factors of this disease. Amoebae can easily adhere to the contact lens surface and transmit to the corneal epithelium. Preventing amoebae adhesion to the contact lens surface could significantly decrease the number of AK infections. Until now, the effective therapy against AK is still under development. Currently proposed therapies are mainly limited to the chlorhexidine digluconate combined with propamidine isethionate or hexamidine applications, which are insufficient and very toxic to the eye. Due to lack of effective treatment, looking for new potential preventive agents is crucial to decrease the number of Acanthamoeba keratitis infections, especially among contact lens users. Nanoparticles have been already included in several novel therapies against bacteria, viruses, fungi, and protist. However, their anti-amoebic potential has not been fully tested yet. The aim of this study was to assess silver nanoparticles (AgNPs) and platinum nanoparticles (PtNPs) anti-amoebic activity and influence on the amoebae adhesion to the surface of four different groups of contact lenses-classified according to the Food and Drugs Administration (FDA) guidelines. The obtained results show that both tested nanoparticles were effective against Acanthamoeba trophozoites and decreased the amoebae adhesion to the contact lens surface. AgNPs showed better anti-amoebic activity to cytotoxicity dependence and reduced amoebae adhesion in a wider spectrum of the tested contact lenses. Our studies also confirmed that ionization next to hydration of the contact lens material is a crucial parameter influencing the Acanthamoeba adhesion to the contact lens surface. In conclusion, silver nanoparticles might be considered as a novel preventive agent against Acanthamoeba keratitis infection.
RESUMO
Naegleria fowleri causes a deadly disease called primary amoebic meningoencephalitis (PAM). Even though PAM is still considered a rare disease, the number of reported cases worldwide has been increasing each year. Among the factors to be considered for this, awareness about this disease, and also global warming, as these amoebae thrive in warm water bodies, seem to be the key factors. Until present, no fully effective drugs have been developed to treat PAM, and the current options are amphotericin B and miltefosine, which present side effects such as liver and kidney toxicity. Statins are able to inhibit the 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, which is a key enzyme for the synthesis of ergosterol of the cell membrane of these amoebae. Therefore, the in vitro activity of a group of statins was tested in this study against two types of strains of Naegleria fowleri. The obtained results showed that fluvastatin was the most effective statin tested in this study and was able to eliminate these amoebae at concentrations of 0.179 ± 0.078 to 1.682 ± 0.775 µM depending on the tested strain of N. fowleri. Therefore, fluvastatin could be a potential novel therapeutic agent against this emerging pathogen.
RESUMO
BACKGROUND: The in vitro activity against Leishmania spp. of a novel group of compounds, phenalenone derivatives, is described in this study. Previous studies have shown that some phenalenones present leishmanicidal activity, and induce a decrease in the mitochondrial membrane potential in L. amazonensis parasites, so in order to elucidate the evidence of programmed cell death occurring inside the promastigote stage, different assays were performed in two different species of Leishmania. METHODS: We focused on the determination of the programmed cell death evidence by detecting the characteristic features of the apoptosis-like process, such as phosphatidylserine exposure, mitochondrial membrane potential, and chromatin condensation among others. RESULTS: The results showed that four molecules activated the apoptosis-like process in the parasite. All the signals observed were indicative of the death process that the parasites were undergoing. CONCLUSIONS: The present results highlight the potential use of phenalenone derivatives against Leishmania species and further studies should be undertaken to establish them as novel leishmanicidal therapeutic agents.
Assuntos
Antiprotozoários/química , Antiprotozoários/farmacologia , Apoptose/efeitos dos fármacos , Leishmania/efeitos dos fármacos , Fenalenos/química , Fenalenos/farmacologia , Humanos , Leishmania/citologia , Leishmania/crescimento & desenvolvimento , Leishmaniose/parasitologia , Estágios do Ciclo de Vida/efeitos dos fármacos , Estrutura MolecularRESUMO
Acanthamoeba is a free-living amoebae genus which is present worldwide in natural and artificial environments. These amoebae are clinically important as causative agents of diseases in humans and other animals such as a fatal encephalitis or a sight threatening Acanthamoeba keratitis (AK). Lately; studies have focused on the search of novel therapeutic options for AK but also to prevent infections. Furthermore; the evaluation of commercialized products seems to be an option for this case since not clinical assays would be required. Thus; we aimed to test the amoebicidal activity of different mixtures of two commercial ophthalmic solutions: Systane® Ultra; which has already shown anti-Acanthamoeba properties; and Naviblef® Daily Care. In addition, we tested their cytotoxic effect against murine macrophages. At the individual level; Naviblef® Daily Care showed to be the most active product against Acanthamoeba spp. Nevertheless; the combinations of Systane® Ultra and Naviblef® Daily Care; showed an improvement in the activity against trophozoites and cysts of Acanthamoeba castellanii Neff. Moreover; the concentration necessary to generate cytotoxic effect against murine macrophages (J774.1) was much higher than the required for the amoebicidal and cysticidal effect achieved in the most effective mixtures.
RESUMO
INTRODUCTION: Saline groundwater desalination has recently emerged as an alternative source of irrigation water in arid and semiarid regions due to the gradual reduction in the quantity and quality of conventional water resources for agricultural use. In Fuerteventura Island (Spain), an extremely arid territory in the European Union, brackish water desalination is one of the few available water sources for agricultural production. Very little research has been conducted on the microbiological quality of this water mainly used for irrigation of vegetable crops. Free-living amoebae (FLA) are widely distributed protozoa in the environment and have been isolated from many environmental sources such as dust, soil and water. Among the pathogenic genera included in this group, Acanthamoeba spp., Naegleria fowleri and Balamuthia mandrillaris have been reported to be causative agents of lethal encephalitis, disseminated infections and keratitis. Particularly, Naegleria fowleri is a pathogenic FLA species which causes primary amoebic meningoencephalitis (PAM). MATERIALS AND METHODS: In the present study, the presence of pathogenic FLA strains on desalinated brackish water samples for irrigation has been evaluated during 7 months. RESULTS: From the analysed samples, only one was positive for Naegleria australiensis. This is the first report of Naegleria spp. in desalinated brackish water for irrigation in Spain.
Assuntos
Irrigação Agrícola , Naegleria/classificação , Naegleria/isolamento & purificação , Água/parasitologia , DNA de Protozoário/genética , Ilhas , EspanhaRESUMO
The original version of this article unfortunately contains a mistake.
RESUMO
Several studies have suggested the existence of a close relationship between antibiotic-resistant phenotypes and resistance to other toxic compounds such as heavy metals, which involve co-resistance or cross-resistance mechanisms. A metagenomic library was previously constructed in Escherichia coli with DNA extracted from the bacterial community inhabiting an acid mine drainage (AMD) site highly contaminated with heavy metals. Here, we conducted a search for genes involved in antibiotic resistance using this previously constructed library. In particular, resistance to antibiotics was observed among five clones carrying four different loci originating from CARN5 and CARN2, two genomes reconstructed from the metagenomic data. Among the three CARN2 loci, two carry genes homologous to those previously proposed to be involved in antibiotic resistance. The third CARN2 locus carries a gene encoding a membrane transporter with an unknown function and was found to confer bacterial resistance to rifampicin, gentamycin, and kanamycin. The genome of Thiomonas delicata DSM 16361 and Thiomonas sp. X19 were sequenced in this study. Homologs of genes carried on these three CARN2 loci were found in these genomes, two of these loci were found in genomic islands. Together, these findings confirm that AMD environments contaminated with several toxic metals also constitute habitats for bacteria that function as reservoirs for antibiotic resistance genes.