RESUMO
In this study, we evaluated the effect of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs), i.e., Phenanthrene, Pyrene and Benzo[a]pyrene, on the radial growth and morphology of the PAH-degrading fungal strains Aspergillus nomius H7 and Trichoderma asperellum H15. The presence of PAHs in solid medium produced significant detrimental effects on the radial growth of A. nomius H7 at 4,000 and 6,000 mg L(-1) and changes in mycelium pigmentation, abundance and sporulation ability at 1,000-6,000 mg L(-1). In contrast, the radial growth of T. asperellum H15 was not affected at any of the doses tested, although sporulation was observed only up to 4,000 mg L(-1) and as with the H7 strain, some visible changes in sporulation patterns and mycelium pigmentation were observed. Our results suggest that fungal strains exposed to high doses of PAHs significantly vary in their growth rates and sporulation characteristics in response to the physiological and defense mechanisms that affect both pigment production and conidiation processes. This finding is relevant for obtaining a better understanding of fungal adaptation in PAH-polluted environments and for developing and implementing adequate strategies for the remediation of contaminated soils.
Assuntos
Aspergillus/crescimento & desenvolvimento , Benzo(a)pireno/farmacologia , Micélio/efeitos dos fármacos , Fenantrenos/farmacologia , Hidrocarbonetos Policíclicos Aromáticos/farmacologia , Pirenos/farmacologia , Esporos Fúngicos/efeitos dos fármacos , Trichoderma/crescimento & desenvolvimento , Aspergillus/efeitos dos fármacos , Aspergillus/metabolismo , Biodegradação Ambiental , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Microbiologia do Solo , Poluentes do Solo , Trichoderma/efeitos dos fármacos , Trichoderma/metabolismoRESUMO
In this study, we evaluated the effect of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs),
Assuntos
Aspergillus/crescimento & desenvolvimento , Benzo(a)pireno/farmacologia , Micélio , Fenantrenos/farmacologia , Hidrocarbonetos Policíclicos Aromáticos/farmacologia , Pirenos/farmacologia , Esporos Fúngicos , Trichoderma/crescimento & desenvolvimento , Aspergillus , Aspergillus/metabolismo , Biodegradação Ambiental , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Microbiologia do Solo , Poluentes do Solo , Trichoderma , Trichoderma/metabolismoRESUMO
In this study, we evaluated the effect of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs),
Assuntos
Aspergillus/crescimento & desenvolvimento , Benzo(a)pireno/farmacologia , Micélio/efeitos dos fármacos , Fenantrenos/farmacologia , Hidrocarbonetos Policíclicos Aromáticos/farmacologia , Pirenos/farmacologia , Esporos Fúngicos/efeitos dos fármacos , Trichoderma/crescimento & desenvolvimento , Aspergillus/efeitos dos fármacos , Aspergillus/metabolismo , Biodegradação Ambiental , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Microbiologia do Solo , Poluentes do Solo , Trichoderma/efeitos dos fármacos , Trichoderma/metabolismoRESUMO
The in vitro activity of four 2-nitropropene derivatives, 1-(3-benzothienyl)-2-nitropropene (N1), 1-(3-thienyl)-2-nitropropene (N2), 1-(5-bromo-2-thienyl)-2-nitropropene (N3) and 1-(4-bromo-2-thienyl)-2-nitropropene (N4), were tested against cultures of the parasite Trypanosoma cruzi. Cytotoxicity studies were performed using Vero cells. The blood trypomastigotes, amastigotes and epimastigotes showed differential degrees of sensitivity towards the four tested compounds; the highest activity against the epimastigotes and blood tripomastigotes was exhibited by N1, followed by N3, N4 and finally N2. In contrast, whereas the compounds N1, N3 and N4 exerted similar magnitudes of activity against amastigotes, N2 was found to be a much less potent compound. According to our results, the compound N1 had the highest level of activity (IC50: 0.6 microM) against epimastigotes.
Assuntos
Antiprotozoários/farmacologia , Nitrocompostos/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Análise de Variância , Animais , Chlorocebus aethiops , Pirenos/farmacologia , Trypanosoma cruzi/crescimento & desenvolvimento , Células VeroRESUMO
The in vitro activity of four 2-nitropropene derivatives, 1-(3-benzothienyl)-2-nitropropene (N1), 1-(3-thienyl)-2-nitropropene (N2), 1-(5-bromo-2-thienyl)-2-nitropropene (N3) and 1-(4-bromo-2-thienyl)-2-nitropropene (N4), were tested against cultures of the parasite Trypanosoma cruzi. Cytotoxicity studies were performed using Vero cells. The blood trypomastigotes, amastigotes and epimastigotes showed differential degrees of sensitivity towards the four tested compounds; the highest activity against the epimastigotes and blood tripomastigotes was exhibited by N1, followed by N3, N4 and finally N2. In contrast, whereas the compounds N1, N3 and N4 exerted similar magnitudes of activity against amastigotes, N2 was found to be a much less potent compound. According to our results, the compound N1 had the highest level of activity (IC50: 0.6 ìM) against epimastigotes.
Assuntos
Animais , Antiprotozoários/farmacologia , Nitrocompostos/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Análise de Variância , Chlorocebus aethiops , Pirenos/farmacologia , Trypanosoma cruzi/crescimento & desenvolvimento , Células VeroRESUMO
There are some foods that contain mutagenic or carcinogenic agents, some of which occur naturally and others that may be formed during preparation or cooking. Several foods such as legumes, also contain natural antimutagens and/or anticarcinogens. Lupine is one such legume that contains high amounts of protein (40%) and oils (14%). About 90 species of lupine have been reported throughout Mexico. However, the use of this crop as a source of food has been limited by the presence of antinutritional agents such as phenolic compounds (PC), carbohydrates (CH) and quinolizidinic alkaloids (Qas). It has also been suggested that consuming these compounds can affect human health and may even reduce the risk of disease. The objective of this work was to determine the effect of PC, CH and Qas, isolated and quantified from Lupinus campestris on the mutagenicity of 1-nitropyrene (1-NP) as a model mutagen and we used the Salmonella typhimurium tester strain YG1024 by the Kado microsuspension method. The results indicate that L. campestris seeds have 11 mg (+)catechin equivalent g(-1) seed coat; 120.3 mg g(-1) seeds and 2.13 mg g(-1) seeds of PC, CH and Qas, respectively. 1-NP mutagenicity was inhibited by 86% for PC, 76% for CH and 75% for Qas at concentrations of 200, 512 and 13.6 microg/tube, respectively.
Assuntos
Antimutagênicos/farmacologia , Lupinus/química , Sementes/química , Alcaloides/análise , Alcaloides/farmacologia , Humanos , Testes de Mutagenicidade/métodos , Oligossacarídeos/análise , Oligossacarídeos/farmacologia , Fenóis/análise , Fenóis/farmacologia , Extratos Vegetais/farmacologia , Pirenos/farmacologia , Quinolizinas/análise , Quinolizinas/farmacologia , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genéticaRESUMO
Polyphenols in fruits, vegetables (e.g., flavonols like quercetin) and tea (e.g., catechins such as epigallocatechin gallate) are good antioxidants with antimutagenic and anticarcinogenic properties. In the present study, the Salmonella typhimurium tester strain YG1024 was used in the plate-incorporation test to examine the antimutagenic effect of phenolic compounds, extracted from common beans (Phaseolus vulgaris), on 1-NP and B[a]P mutagenicity. Dose-response curves for 1-NP and B[a]P were obtained; the number of net revertants/plate at the peak mutagenic dosage were 880 for 1-NP and 490 for B[a]P. For the antimutagenicity studies doses of 0.1 microg/plate and 2 microg/plate for 1-NP and B[a]P, respectively, were chosen. We obtained a dose-response curve of ellagic acid (EA) against B[a]P and 1-NP mutagenicity. To test the bean extract, a dose of 300 microg/plate of EA was chosen as the antimutagenic control. The EA and bean extracts were not toxic to the bacteria at the concentrations tested. The inhibitory effects of the bean extracts and EA against B[a]P mutagenicity were dose-dependent. The percentages of inhibition produced against B[a]P (2 microg/plate) using 300 microg/plate of EA and for the extracts 500 microg equivalent catechin/plate were 82%, 83%, 81% and 83% for EA, water extract, water/methanol extract and methanol extract, respectively. However, for 1-NP mutagenicity, only the methanolic extract from beans showed an inhibitory effect. These results suggest that common beans, as other legumes, can function as health-promoting foods.
Assuntos
Antimutagênicos/farmacologia , Fabaceae/química , Fenóis/farmacologia , Extratos Vegetais/farmacologia , Plantas Medicinais , Antimutagênicos/isolamento & purificação , Benzo(a)pireno/farmacologia , Catequina/farmacologia , Relação Dose-Resposta a Droga , Testes de Mutagenicidade , Fenóis/isolamento & purificação , Pirenos/farmacologia , Salmonella typhimurium/efeitos dos fármacosRESUMO
Calcium-activated phosphoenolpyruvate carboxykinase from Escherichia coli is not inactivated by a number of sulfhydryl-directed reagents [5,5'-dithiobis(2-nitrobenzoate), iodoacetate, N-ethylmaleimide, N-(1-pyrenyl)maleimide or N-(iodoacetyl)-N'-(5-sulfo-1-naphthylethylenediamine)], unlike phosphoenolpyruvate carboxykinase from other organisms. On the other hand, the enzyme is rapidly inactivated by the arginyl-directed reagents 2,3-butanedione and 1-pyrenylglyoxal. The substrates, ADP plus PEP in the presence of Mn2+, protect the enzyme against inactivation by the diones. Quantitation of pyrenylglyoxal incorporation indicates that complete inactivation correlates with the binding of one inactivator molecule per mole of enzyme. Chemical modification by pyridoxal 5'-phosphate also produces inactivation of the enzyme, and the labeled protein shows a difference spectrum with a peak at 325 nm, characteristic of a pyridoxyl derivative of lysine. The inactivation by this reagent is also prevented by the substrates. Binding stoichiometries of 1.25 and 0.30 mol of reagent incorporated per mole of enzyme were found in the absence and presence of substrates, respectively. The results suggest the presence of functional arginyl and lysyl residues in or near the active site of the enzyme, and indicate lack of reactive functional sulfhydryl groups.
Assuntos
Arginina , Cisteína , Escherichia coli/enzimologia , Lisina , Fosfoenolpiruvato Carboxiquinase (GTP)/metabolismo , Sítios de Ligação , Diacetil/farmacologia , Glioxal/análogos & derivados , Glioxal/farmacologia , Cinética , Fosfoenolpiruvato Carboxiquinase (GTP)/antagonistas & inibidores , Fosfoenolpiruvato Carboxiquinase (GTP)/química , Pirenos/farmacologia , Fosfato de Piridoxal/metabolismo , Fosfato de Piridoxal/farmacologia , Reagentes de Sulfidrila/farmacologiaRESUMO
Fluorescence quenching by oxygen of cationic [pyrene-(CH2)nN(CH3)3+; n = 1, 4, and 11] and anionic [pyrene-(CH2)nCO2-, n = 3, 8, 11, and 15] probes was investigated in erythrocyte plasma membranes (leaky) in order to assess the ability of oxygen molecules to interact with solutes located at different positions in the membrane. The pseudounimolecular quenching rate constants measured increase, both for cationic and anionic probes, when n increases. These results are interpreted in terms of an increased oxygen solubility toward the center of the membrane interior, and imply that lateral diffusion contributes more than transverse diffusion to total oxygen mobility. For all of the probes considered, quenching rates increase when n-alkanols are added. The effect observed increases when n decreases and when the size of the n-alkanol alkyl chain increases. Arrhenius-type plots for the quenching rate constants show noticeable downward curvatures. Average (0-40 degrees C) activation energies are approximately 6 kcal/mol.