RESUMO
In this study we described the synthesis of a hybrid polysaccharide harboring moieties of ulvan and kappa-carrabiose. Alkylamines (1,3-diaminopropane and 1,6-diaminohexane) were selectively inserted into ß-D-GlcAp and α-L-IdoAp units in the ulvan structure via an amide bond formation producing ulvan-amide derivatives F-DAP (N% = 1.77; Mw = 208 kg mol-1) and F-DAH (N% = 1.77; Mw = 202 kg mol-1), which were reacted with kappa-carrabiose via reductive amination to produce hybrid ulvan-kappa-carrabiose polysaccharides F-DAP-Kb (N% = 1.56; Mw = 206 kg mol-1) and F-DAH-Kb (N% = 1.16; Mw = 200 kg mol-1). All the ulvan derivatives were characterized by 1H and 13C NMR spectroscopy and did not show cytotoxicity against human dermal fibroblasts (HDFa) at the concentrations of 25, 100, and 500 µg mL-1, neither anticoagulant properties at the range of 10-150 µg mL-1. Therefore, the ulvan-amide derivatives and the hybrid ulvan-kappa-carrabiose polysaccharides showed good biocompatibility in vitro, presenting as worthy candidates for tailoring scaffolds for biomedical applications.
Assuntos
Anticoagulantes/farmacologia , Carragenina/farmacologia , Polissacarídeos/farmacologia , Anticoagulantes/síntese química , Anticoagulantes/toxicidade , Carragenina/síntese química , Carragenina/toxicidade , Fibroblastos/efeitos dos fármacos , Humanos , Tempo de Tromboplastina Parcial , Polissacarídeos/síntese química , Polissacarídeos/toxicidadeRESUMO
Substance P (SP) is involved in fever that is induced by lipopolysaccharide (LPS) but not by interleukin-1ß or macrophage inflammatory protein-1α. Intracerebroventricular (i.c.v.) administration of the neurokinin-1 (NK1) receptor antagonist SR140333B in rats reduced fever that was induced by an i.c.v. injection of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), prostaglandin E2 (PGE2), corticotropin-releasing factor (CRF), endothelin-1 (ET-1), and morphine (MOR). Furthermore, an i.c.v. injection of SP induced a febrile response that was inhibited by indomethacin concomitant with an increase in PGE2 levels in cerebrospinal fluid. Lipopolysaccharide and PGE2 caused higher expression and internalization of NK1 receptors in the hypothalamus which were prevented by SR140333B. These data suggest that SP is an important mediator of fever, in which it induces a prostaglandin-dependent response and is released after TNF-α, IL-6, PGE2, CRF, endogenous opioids, and ET-1.
Assuntos
Dinoprostona/líquido cefalorraquidiano , Febre/induzido quimicamente , Febre/prevenção & controle , Pirogênios , Substância P/farmacologia , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Temperatura Corporal/efeitos dos fármacos , Hormônio Liberador da Corticotropina/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Indometacina/farmacologia , Interleucina-6/administração & dosagem , Interleucina-6/metabolismo , Masculino , Morfina/farmacologia , Polissacarídeos/toxicidade , Ratos , Ratos Wistar , Receptores da Neurocinina-1/metabolismo , Substância P/metabolismo , Fatores de Tempo , Tropanos/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
Trebouxia sp. is a genus of green algae that is a symbiotic partner of lichenized fungi. Previous studies conduced demonstrated that Trebouxia sp. is able to produce galactofuranose-rich polysaccharides (ß-d-galactofuranan, mannogalactofuranan), which were able to activate macrophages in vitro. The present study was proposed to investigate the effects of SK10 polysaccharides fraction from Trebouxia sp. on the model of polymicrobial sepsis induced by cecal ligation and puncture in mice in vivo. The subcutaneous administration of SK10 increased the late mortality rate by 20%, stimulated neutrophil accumulation in lungs (indirectly measured through myeloperoxidase activity) and also Interleukin-1ß, creatinine and glucose serum levels. Moreover this study demonstrates the in vivo proinflammatory effects of polymers of galactofuranose and that they can act as pathogen-associated molecular patterns being highly recognized by the immune system of mammals, even if they come from a non-pathogenic microorganism.
Assuntos
Clorófitas/química , Inflamação/induzido quimicamente , Polissacarídeos/toxicidade , Sepse/induzido quimicamente , Análise de Variância , Animais , Glicemia/metabolismo , Creatinina/sangue , Galactose/química , Inflamação/sangue , Interleucina-1beta/sangue , Pulmão/efeitos dos fármacos , Pulmão/patologia , Masculino , Camundongos , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Neutrófilos/patologia , Polissacarídeos/química , Sepse/sangue , Sepse/mortalidade , Sesquiterpenos/química , Sesquiterpenos/toxicidade , Taxa de SobrevidaRESUMO
Herpes simplex virus (HSV) is one of the most regular human pathogens, being a public health problem, and causal agent of several diseases. Poliovirus (PV) is an enteric virus and about 1% of infected individuals develop paralytic poliomyelitis due to viral invasion of the central nervous system and destruction of motor neurons. This work evaluated the activity of a sulfated polysaccharide of Caesalpinia ferrea (SPLCf) in HSV and PV replication. The antiviral effect of SPLCf at varying concentrations was tested by plaque assay under several protocols, such as time-of-addition, adsorption and penetration inhibition and virucidal. Syntheses of viral protein and nucleic acid were also monitored by the immunofluorescence assay and PCR. The SPLCf inhibited virus adsorption and steps after penetration, and inhibited the synthesis of viral protein. Virucidal effect was also shown and nucleic acid synthesis was concurrent with positive results. Our findings suggested that the substance with low toxicity represent a potential viral inhibitor.
Assuntos
Antivirais/farmacologia , Caesalpinia/química , Extratos Vegetais/química , Poliovirus/efeitos dos fármacos , Polissacarídeos/farmacologia , Simplexvirus/efeitos dos fármacos , Antivirais/química , Antivirais/toxicidade , Linhagem Celular , Humanos , Ressonância Magnética Nuclear Biomolecular , Polissacarídeos/química , Polissacarídeos/toxicidade , Espectroscopia de Infravermelho com Transformada de Fourier , Ensaio de Placa Viral , Replicação Viral/efeitos dos fármacosRESUMO
BACKGROUND: Semiconductor Quantum dots (QDs) have become quite popular thanks to their properties and wide use in biological and biomedical studies. However, these same properties entail new challenges in understanding, predicting, and managing potential adverse health effects following exposure. Cadmium and selenium, which are the major components of the majority of quantum dots, are known to be acutely and chronically toxic to cells and organisms. Protecting the core of nanoparticles can, to some degree, control the toxicity related to cadmium and selenium leakage. RESULTS: This study successfully synthesized and characterized maltodextrin coated cadmium sulfide semiconductor nanoparticles. The results show that CdS-MD nanoparticles are cytotoxic and embryotoxic. CdS-MD nanoparticles in low concentrations (4.92 and 6.56 nM) lightly increased the number of HepG2 cell. A reduction in MDA-MB-231 cells was observed with concentrations higher than 4.92 nM in a dose response manner, while Caco-2 cells showed an important increase starting at 1.64 nM. CdS-MD nanoparticles induced cell death by apoptosis and necrosis in MDA-MD-231 cells starting at 8.20 nM concentrations in a dose response manner. The exposure of these cells to 11.48-14.76 nM of CdS-MD nanoparticles induced ROS production. The analysis of cell proliferation in MDA-MB-231 showed different effects. Low concentrations (1.64 nM) increased cell proliferation (6%) at 7 days (p < 0.05). However, higher concentrations (>4.92 nM) increased cell proliferation in a dose response manner (15-30%) at 7 days. Exposures of chicken embryos to CdS-MD nanoparticles resulted in a dose-dependent increase in anomalies that, starting at 9.84 nM, centered on the heart, central nervous system, placodes, neural tube and somites. No toxic alterations were observed with concentrations of < 3.28 nM, neither in cells nor chicken embryos. CONCLUSIONS: Our results indicate that CdS-MD nanoparticles induce cell death and alter cell proliferation in human cell lines at concentrations higher than 4.92 nM. We also demonstrated that they are embryotoxic. However, no toxic effects were observed with doses lower than 3.28 nM in neither cells nor chicken embryos. The CdS-MD nanoparticles used in this study can be potentially used in bio-imaging applications. However, further studies using mammalian species are required in order to discard more toxic effects.
Assuntos
Compostos de Cádmio/química , Compostos de Cádmio/toxicidade , Polissacarídeos/química , Polissacarídeos/toxicidade , Pontos Quânticos , Sulfetos/química , Sulfetos/toxicidade , Anormalidades Induzidas por Medicamentos/etiologia , Animais , Apoptose/efeitos dos fármacos , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Embrião de Galinha , Desenvolvimento Embrionário/efeitos dos fármacos , Células Hep G2 , Humanos , Estresse Oxidativo/efeitos dos fármacosRESUMO
The aim was to synthesize and characterize fucoidan-coated poly(isobutylcyanoacrylate) nanoparticles. The nanoparticles were prepared by anionic emulsion polymerization (AEP) and by redox radical emulsion polymerization (RREP) of isobutylcyanoacrylate using fucoidan as a new coating material. The nanoparticles were characterized, and their cytotoxicity was evaluated in vitro on J774 macrophage and NIH-3T3 fibroblast cell lines. Cellular uptake of labeled nanoparticles was investigated by confocal fluorescence microscopy. Results showed that both methods were suitable to prepare stable formulations of fucoidan-coated PIBCA nanoparticles. Stable dispersions of nanoparticles were obtained by AEP with up to 100% fucoidan as coating material. By the RREP method, stable suspensions of nanoparticles were obtained with only up to 25% fucoidan in a blend of polysaccharide composed of dextran and fucoidan. The zeta potential of fucoidan-coated nanoparticles was decreased depending on the percentage of fucoidan. It reached the value of -44 mV for nanoparticles prepared by AEP with 100% of fucoidan. Nanoparticles made by AEP appeared more than four times more cytotoxic (IC(50) below 2 µg/mL) on macrophages J774 than nanoparticles made by RREP (IC(50) above 9 µg/mL). In contrast, no significant difference in cytotoxicity was highlighted by incubation of the nanoparticles with a fibroblast cell line. On fibroblasts, both types of nanoparticles showed similar cytotoxicity. Confocal fluorescence microscopy observations revealed that all types of nanoparticles were taken up by both cell lines. The distribution of the fluorescence in the cells varied greatly with the type of nanoparticles.
Assuntos
Antineoplásicos/toxicidade , Sistemas de Liberação de Medicamentos , Nanopartículas/toxicidade , Polissacarídeos/toxicidade , Adsorção , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Linhagem Celular , Cianoacrilatos/química , Cianoacrilatos/toxicidade , Composição de Medicamentos , Avaliação Pré-Clínica de Medicamentos , Emulsões , Embucrilato , Excipientes/química , Fibroblastos/efeitos dos fármacos , Fibroblastos/fisiologia , Fluorescência , Formazans/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/fisiologia , Camundongos , Microscopia Confocal , Nanopartículas/química , Tamanho da Partícula , Phaeophyceae , Fitoterapia , Extratos Vegetais , Polimerização , Polissacarídeos/química , Polissacarídeos/metabolismo , Sais de Tetrazólio/metabolismoRESUMO
CONTEXT: Lobophora variegata J.V. Lamouroux (Dictyotaceae) is a brown marine alga widely encountered in the Brazilian sea coast that presents high content of fucans. Anti-inflammatory effects of fucans are reported mostly in models in vitro, but little is known about its effects in vivo. OBJECTIVE: To investigate vascular and cellular effects of a sulfated polysaccharide from the brown marine algae L. variegata (SP-Lv) in acute inflammatory models. MATERIALS AND METHODS: SP-Lv was isolated by DEAE-cellulose and analyzed by agarose gel electrophoresis and evaluated for its inhibitory effect on paw edema, vascular permeability, leukocyte migration and peritoneal nitrite content induced by zymosan in Wistar rats. Anticoagulant activities and possible systemic toxicity were also evaluated. RESULTS: SP-Lv inhibited the paw edema (120 min: 1.42 ± 0.11 vs. 0.95 ± 0.05 mL), plasma exudation (21.53 ± 0.62 vs. 11.96 ± 0.68 µg/g), nitrite content (4.42 ± 0.33 vs. 2.86 ± 0.003 µM) and leukocyte migration (5.15 ± 1.21 vs. 1.99 ± 0.16 cells/10(3) mL) induced by zymosan. SP-Lv and L-NAME reduced the paw edema (60-120 min) elicited by L-arginine. However, at 180 min SP-Lv effect was more accentuated and sustained until 240 min, while that of L-NAME was abolished. Similarly to indomethacin, SP-Lv inhibited the entire edema time-course induced by phospholipase A(2), except for the time of 60 min. DISCUSSION AND CONCLUSION: The anti-edematogenic effect of SP-Lv seems to occur via inhibition of nitric oxide synthase and cyclooxygenase activities. These results suggest a potential applicability of polysaccharides from alga origin in acute inflammatory conditions.
Assuntos
Anti-Inflamatórios/farmacologia , Inflamação/tratamento farmacológico , Phaeophyceae/química , Polissacarídeos/farmacologia , Animais , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/toxicidade , Anticoagulantes/isolamento & purificação , Anticoagulantes/farmacologia , Anticoagulantes/toxicidade , Brasil , Modelos Animais de Doenças , Edema/tratamento farmacológico , Edema/fisiopatologia , Eletroforese em Gel de Ágar , Indometacina/farmacologia , Inflamação/fisiopatologia , Masculino , Óxido Nítrico Sintase/antagonistas & inibidores , Polissacarídeos/isolamento & purificação , Polissacarídeos/toxicidade , Prostaglandina-Endoperóxido Sintases/efeitos dos fármacos , Prostaglandina-Endoperóxido Sintases/metabolismo , Ratos , Ratos Wistar , Fatores de TempoRESUMO
Fucan is a term used to denominate a family of sulfated polysaccharides rich in L-fucose. They are extracted mainly from brown seaweeds and echinoderms. The brown seaweed Spatoglossum schröederi (Dictyotaceae) synthesizes three heterofucans named A, B and C. Our research group purified a non-anticoagulant heterofucan (fucan A) which displays antithrombotic activity in vivo. However, its in vitro toxicity has yet to be determined. This work presents the evaluation of the potential cytotoxicity, mutagenicity and genotoxicity of this fucan. After 48 h incubation fucan A cytotoxicity was determinate using MTT assay. Tumor-cell (HeLa, PC3, PANC, HL60) proliferation was inhibited 2.0-43.7%; at 0.05-1 mg ml⻹ of the heterofucan, the 3T3 non-tumor cell line proliferation was also inhibited (3.3-22.0%). On the other hand, the CHO tumorigenic and RAW non-tumor cell lines proliferation were not affected by this molecule (0.05-1 mg ml⻹). We observed no mutagenic activity in Salmonella reversion assay when bacterial strains TA97a, TA98, TA100 and TA102 (with and without S9) were used.Comet assay showed that fucan A had no genotoxic effect (from 20 to 1000 mg ml⻹) on CHO cells. In conclusion, this study indicates that the S. schröederi fucan A was not found to be genotoxic or mutagenic compound; thus it could be used in new antithrombotic drug development.
Assuntos
Dano ao DNA , Fibrinolíticos/farmacologia , Fibrinolíticos/toxicidade , Mutagênicos/farmacologia , Neoplasias/patologia , Trombina/antagonistas & inibidores , Animais , Anticoagulantes/farmacologia , Células CHO , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Equinodermos/química , Fucose/farmacologia , Células HL-60 , Células HeLa , Humanos , Phaeophyceae/química , Polissacarídeos/toxicidade , Sulfatos/farmacologiaRESUMO
Sulfated polysaccharides from marine invertebrates have well-defined structures and constitute a reliable class of molecules for structure-activity relationship studies. We tested the effects of two of these polysaccharides, namely a sulfated fucan and a fucosylated chondroitin sulfate, on coagulation, thrombosis and bleeding. The compounds share similar 2,4-disulfated fucose units, which are required for high anticoagulant activity in this class of polymer. These residues occur either as branches in fucosylated chondroitin sulfate or as components of the linear chain in the sulfated fucan. These polysaccharides possess anticoagulant activity but differ significantly in their mechanisms of action. The fucosylated chondroitin sulfate inhibits thrombin by heparin cofactor II, whereas sulfated fucan inhibits thrombin by both antithrombin and heparin cofactor II. In addition, these polysaccharides also have serpin-independent anticoagulant activities. Fucosylated chondroitin sulfate, but not sulfated fucan, activates factor XII. As a result of the complex anticoagulant mechanism, the invertebrate polysaccharides differ in their effects on experimental thrombosis. For instance, the sulfated fucan inhibits venous thrombosis at lower doses than fucosylated chondroitin sulfate. In contrast, fucosylated chondroitin sulfate is significantly more potent than sulfated fucan in arterial thrombosis. Finally, fucosylated chondroitin sulfate increases bleeding, while sulfated fucan has only a discrete effect. In conclusion, the location of 2,4-disulfated fucose units in the polysaccharide chains dictates the effects on coagulation, thrombosis and bleeding.
Assuntos
Anticoagulantes/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Sulfatos de Condroitina/farmacologia , Fibrinolíticos/farmacologia , Fucose/química , Hemorragia/induzido quimicamente , Polissacarídeos/farmacologia , Trombose/tratamento farmacológico , Animais , Anticoagulantes/química , Anticoagulantes/isolamento & purificação , Anticoagulantes/uso terapêutico , Anticoagulantes/toxicidade , Configuração de Carboidratos , Sequência de Carboidratos , Trombose das Artérias Carótidas/tratamento farmacológico , Sulfatos de Condroitina/química , Sulfatos de Condroitina/isolamento & purificação , Sulfatos de Condroitina/uso terapêutico , Sulfatos de Condroitina/toxicidade , Avaliação Pré-Clínica de Medicamentos , Ativação Enzimática/efeitos dos fármacos , Fator XII/metabolismo , Feminino , Fibrinolíticos/química , Fibrinolíticos/isolamento & purificação , Fibrinolíticos/uso terapêutico , Fibrinolíticos/toxicidade , Masculino , Dados de Sequência Molecular , Estrutura Molecular , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Polissacarídeos/uso terapêutico , Polissacarídeos/toxicidade , Ratos , Ratos Wistar , Pepinos-do-Mar/química , Relação Estrutura-Atividade , Trombose Venosa/tratamento farmacológicoRESUMO
Brea gum is a phloematic exudate from Parkinsonia praecox, an autoctonous tree that grows in the arid areas of Argentina. In this work, we propose its potential as a food additive. However, as no toxicological safety evaluation of brea gum has yet been reported, this preliminary study was conducted to evaluate its long-term toxicity over a 120-day period in BALB/c mice fed with brea gum at various levels in the diet. The results showed that animals on diets containing up to 5% brea gum were healthy, exhibiting growth curves similar to controls for both males (P = 0.9138) and females (P = 0.9459), thereby indicating that feed intake and utilization was not affected. A histopathological examination and weight recording of liver, kidneys, and intestine did not reveal any microscopic abnormalities or adverse toxicological effect (weights respect to control: P > 0.1). Moreover, hematological parameters and enzyme activities were within the normal values previously reported for mice. Our findings suggest that feeding brea gum at levels up to 5% to BALB/c mice do not exert any toxicological effects, supporting its potential use as a food additive for human consumption.
Assuntos
Antioxidantes/toxicidade , Carboidratos da Dieta/efeitos adversos , Aditivos Alimentares/efeitos adversos , Polissacarídeos/toxicidade , Administração Oral , Ração Animal , Animais , Antioxidantes/administração & dosagem , Argentina , Carcinógenos/toxicidade , Dieta , Carboidratos da Dieta/administração & dosagem , Fabaceae/química , Feminino , Aditivos Alimentares/administração & dosagem , Humanos , Fígado/efeitos dos fármacos , Masculino , Camundongos , Modelos Animais , Testes de Mutagenicidade , Tamanho do Órgão , Extratos Vegetais/farmacologia , Plantas Geneticamente Modificadas , Polissacarídeos/administração & dosagemRESUMO
In recent years, much attention has been focused on polysaccharides isolated from natural sources. The aim of this study was to investigate the in vitro and in vivo antitumor properties of a sulfated polysaccharide isolated from the seaweed C. feldmannii (Cf-PLS). Hematological, biochemical and histopathological analyses were performed in order to evaluate the toxicological aspects related to Cf-PLS treatment. Its effects on the immunological system were also investigated. The Cf-PLS did not show any significant in vitro cytotoxicity at the experimental exposure levels that were used, but showed in vivo antitumor effect. The inhibition rates of sarcoma 180 tumor development were 48.62 and 48.16% at the doses of 10 and 25 mg kg(-1), respectively. In addition, Cf-PLS was also able to increase the response elicited by 5-fluorouracil (5-FU) from 48.66 to 68.32%. The histopathological analysis of liver and kidney showed that both organs were moderately affected by Cf-PLS-treatment. Neither enzymatic activity of alanine aminotransferase nor urea or creatinine levels were significantly altered. In hematological analysis, leucopeny was observed after 5-FU treatment, but this effect was prevented when the treatment was associated with the Cf-PLS. It was also demonstrated that Cf-PLS acts as an immunomodulatory agent, raising the production of specific antibodies, and increasing the production of OVA-specific antibodies. It also induced a discreet hyperplasia of lymphoid folicules of the white pulp in the spleen of treated mice. In conclusion, Cf-PLS has some interesting anticancer activity that could be associated with its immunostimulating properties.
Assuntos
Antineoplásicos/farmacologia , Linhagem Celular Tumoral/efeitos dos fármacos , Polissacarídeos/farmacologia , Rodófitas/química , Sarcoma 180/tratamento farmacológico , Animais , Formação de Anticorpos/efeitos dos fármacos , Antineoplásicos/toxicidade , Linhagem Celular Tumoral/patologia , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Sinergismo Farmacológico , Quimioterapia Combinada , Feminino , Fluoruracila/farmacologia , Humanos , Fatores Imunológicos/farmacologia , Fatores Imunológicos/toxicidade , Camundongos , Extratos Vegetais/farmacologia , Extratos Vegetais/toxicidade , Polissacarídeos/toxicidade , Sarcoma 180/patologia , Alga Marinha , Sulfatos/farmacologia , Sulfatos/toxicidade , Testes de ToxicidadeRESUMO
AIMS: Agaricus brasiliensis (previously named Agaricus blazei ss. Heinem), also known as the sun mushroom is native of Southeast Brazil, and is widely consumed, mainly in the form of tea, due to its nutritional and pharmacological properties. In this study, we tested aqueous (AqE) and ethanol (EtOHE) extracts and an isolated polysaccharide (PLS) from the fruiting body of A. brasiliensis, for antiviral activity against poliovirus type 1 in HEp-2 cells. METHODS AND RESULTS: The evaluation of the time of addition by plaque assay showed that when AqE, PLS and EtOHE were added, just after the virus inoculation (time 0 h), there was a concentration-dependent reduction in the number of plaques up to 50%, 67% and 88%, respectively, with a selectivity index (SI) of 5.4, 9.9 and 12.3, respectively. CONCLUSIONS: The test substances showed antiviral activity and were more effective when added during the poliovirus infection. As they had little effect on reducing viral adsorption and did not show any virucidal effect, we suggest that they act at the initial stage of the replication of poliovirus. SIGNIFICANCE AND IMPACT OF THE STUDY: These results corroborate that basidiomycetes can be a rich source of potential antiviral compounds.
Assuntos
Agaricus/química , Antivirais , Poliovirus/efeitos dos fármacos , Polissacarídeos , Replicação Viral/efeitos dos fármacos , Agaricus/crescimento & desenvolvimento , Antivirais/isolamento & purificação , Antivirais/farmacologia , Antivirais/toxicidade , Linhagem Celular Tumoral , Etanol/química , Humanos , Testes de Sensibilidade Microbiana , Poliovirus/fisiologia , Polissacarídeos/isolamento & purificação , Polissacarídeos/farmacologia , Polissacarídeos/toxicidade , Água/químicaRESUMO
Two sets of Saccharomyces cerevisiae strains were compared for their physiological responses to different stress conditions. One group is composed of three strains adapted to controlled laboratory conditions (CEN.PK, LR88 and RS58), whereas the other consisted of five industrial strains (IND1101, SuperStart, LO24, LO41 and Azteca). Most industrial strains showed higher tolerance to heat shock and to an oxidative environment than laboratory strains. Excluding CEN.PK, a similar behavior was observed regarding ethanol production in high sugar concentrations (180 g/l glucose). Addition of acetate (10 g/l) or furfural (2 g/l), in concentrations similar to those found in sugar cane bagasse hydrolysates, decreased cell mass formation and growth rate in almost all strains. CEN.PK and SuperStart showed the highest sensitivity when grown in furfural-containing medium. Acetic acid treatment severely affected cell mass formation and reduced growth rate in all strains; CEN.PK and LO24 were the most resistant. The specific ethanol production rate was not affected by furfural addition. However, specific ethanol production rates decreased in response to acetic acid in four industrial strains, and increased in all laboratory strains and in LO24. No significant correlation was found between the stress tolerance of the strains tested and the transcript accumulation of genes selected by their involvement in the response to each of the stressful environments applied.
Assuntos
Adaptação Fisiológica , Saccharomyces cerevisiae/fisiologia , Ácido Acético/farmacologia , Biomassa , Etanol/metabolismo , Congelamento , Furaldeído/farmacologia , Regulação Fúngica da Expressão Gênica , Glucose/metabolismo , Inibidores do Crescimento/farmacologia , Temperatura Alta , Concentração Osmolar , Estresse Oxidativo , Polissacarídeos/química , Polissacarídeos/toxicidade , RNA Fúngico/análise , RNA Mensageiro/análise , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismoRESUMO
Glucuronoxylomannan (GXM), the major capsular polysaccharide of Cryptococcus neoformans, is the most important virulence factor of this fungus. We analyzed the molecular events related to protective immune responses against a non-encapsulated strain of C. neoformans, mediated by murine splenic CD4(+) T lymphocytes in vitro, and the impact of GXM addition upon these events. Both the lymphoproliferation of CD4(+) T cells and the control of fungus growth were dependent on B7 co-stimulation. Addition of GXM did not modify CD4(+) T cell proliferation, but exacerbated infection in cultures obtained from normal and infected hosts. GXM enhanced the secretion of IL-10 and IL-4, while it reduced the production of pro-inflammatory cytokines TNF-alpha and IFN-gamma. The blockade of IL-10 activity with neutralizing antibodies increased TNF-alpha production and reduced yeast cell growth. The findings suggest that GXM exacerbates infection by down-regulating cell-mediated protective immune response and that IL-10 is implicated in yeast evasion.
Assuntos
Linfócitos T CD4-Positivos/efeitos dos fármacos , Cryptococcus neoformans/imunologia , Interleucina-10/fisiologia , Polissacarídeos/toxicidade , Leveduras/crescimento & desenvolvimento , Animais , Antígeno B7-1/fisiologia , Linfócitos T CD4-Positivos/imunologia , Interferon gama/biossíntese , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Three fractions of fucoidans isolated from the brown seaweed Leathesia difformis (Ee, Ec and Ea) were found to be selective antiviral agents against herpes simplex virus (HSV) types 1 and 2 and human cytomegalovirus. Fraction Ea was the most active, with IC50 values in the range 0.5-1.9 microg/ml without affecting cell viability at concentrations up to 400 microg/ml. The antiherpetic activity of Ea was assessed by three different methods, plaque reduction, inhibition of virus yield and prevention of HSV-2 induced shut-off of cell protein synthesis, demonstrating that the inhibitory effect was independent of the antiviral assay and the multiplicity of infection. The mode of action of Ea could be ascribed to an inhibitory action on virus adsorption. The fucoidans did not inhibit the blood coagulation process even at concentrations exceeding more than 100 times the IC50 value.
Assuntos
Antivirais/farmacologia , Phaeophyceae/química , Polissacarídeos/farmacologia , Adsorção/efeitos dos fármacos , Animais , Anticoagulantes/farmacologia , Anticoagulantes/toxicidade , Antivirais/toxicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Chlorocebus aethiops/virologia , Herpesvirus Humano 2/efeitos dos fármacos , Herpesvirus Humano 2/fisiologia , Humanos , Concentração Inibidora 50 , Polissacarídeos/toxicidade , Alga Marinha/química , Células VeroRESUMO
The most active polysaccharides which show anti-tumoral activity are (1-->3)-beta-D-glucans, branched or not at O-6. Since these structures are sometimes poorly soluble in aqueous media, alpha-D-glucans and their chemical derivatives, which are more soluble, were also studied. The present object is to observe morphological alterations in HeLa cells caused by two different polysaccharides obtained from the lichen Ramalina celastri, which are (1-->3),(1-->4)-linked alpha-D-glucan and its sulphated derivative. The cells were incubated in Eagle's medium in the absence or presence of each polysaccharide and routinely processed and analysed by light and electron microscopy. Even though the alpha-D-glucan altered the cellular volume, cytoplasmic densities, and mitosis, the resulting monolayer was similar to the control. TEM analysis showed cytoplasmic blebbing and the presence of an amorphous electron-dense material free in the cytoplasm and interior membranes. The enhanced injury caused by the sulphated derivative was apparent, altering cell adhesion and causing cell aggregation. Nuclear modifications such as fragmentation and condensation of chromatin under the nuclear envelope, which showed to be convoluted, suggested the occurrence of cell death by apoptosis.
Assuntos
Células HeLa/efeitos dos fármacos , Células HeLa/patologia , Líquens/metabolismo , Polissacarídeos/toxicidade , Células HeLa/ultraestrutura , Humanos , Microscopia EletrônicaRESUMO
The occurrence of a polysaccharide fraction of Paracoccidioides brasiliensis cell wall with toxic, granuloma-inducing and macrophage-stimulating activities was demonstrated. After fractionation of the lipid-extracted wall with 1 M-NaOH, three fractions were obtained: (1) an alkali-insoluble fraction; (2) an alkali-soluble, acid-insoluble fraction and (3) an alkali-soluble, acid-soluble fraction. When the three fractions were injected into mice only fraction (1) was able to induce chronic lung inflammation, causing a marked loss in body weight and death at a dose of 6 mg per animal. Analysis of the stimulation of peritoneal macrophages of mice (measured by cell spreading on glass) after intraperitoneal injection of fraction 1 showed that 75% of the cells were able to spread even 20 d after inoculation.