RESUMEN
AIMS: To evaluate the anti-staphylococcal effects of lectins isolated from bark (MuBL), heartwood (MuHL) and leaves (MuLL) of Myracrodruon urundeuva. METHODS AND RESULTS: The lectins were evaluated for: effects on growth, aggregation, haemolytic activity and biofilm-forming ability of Staphylococcus aureus clinical isolates nonresistant (8325-4) and multidrug resistant (LAC USA300); interference with the expression of virulence genes (hla, rnaIII and spa) of the Agr system of S. aureus; and synergistic effect with the antibiotics cefoxitin and cefotaxime. MuBL, MuHL and MuLL reduced growth (minimal inhibitory concentration (MIC): 12·5-50 µg ml-1 ) and viability (minimal bactericidal concentration (MBC): 100 µg ml-1 ) of 8325-4 and LAC USA300 cells. MuLL (at ½MIC and MIC) reduced LAC USA300 agglutination. The lectins did not interfere with haemolytic activity and expression of hla, rnaIII and spa genes. Only MuHL was able to reduce the biofilm production by 8325-4 (50-400 µg ml-1 ) and LAC USA300 (400 µg ml-1 ). CONCLUSION: The M. urundeuva lectins showed antibacterial activity against nonresistant and resistant clinical isolates of S. aureus and synergistic effects with antibiotics in reducing growth and biofilm formation. SIGNIFICANCE AND IMPACT OF THE STUDY: This work reports bioactive molecules capable of acting as anti-staphylococcal agents, since there are increasing reports of multiresistant isolates of this bacterium.
Asunto(s)
Anacardiaceae/química , Antibacterianos/farmacología , Lectinas de Plantas/farmacología , Staphylococcus aureus/efectos de los fármacos , Pruebas de Aglutinación , Antibacterianos/aislamiento & purificación , Biopelículas/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple , Sinergismo Farmacológico , Hemólisis/efectos de los fármacos , Humanos , Lectinas de Plantas/aislamiento & purificación , Staphylococcus aureus/aislamiento & purificación , Staphylococcus aureus/patogenicidad , Virulencia/efectos de los fármacosRESUMEN
AIMS: To investigate the effects of the lectin from Punica granatum sarcotesta (PgTeL) on growth, viability, cell structure, biofilm formation and chitinase activity of Listeria monocytogenes. In addition, the effect of PgTeL on the adhesion and invasion of human cells (HeLa) was determined. METHODS AND RESULTS: PgTeL showed bacteriostatic and bactericidal effects on the strains L. monocytogenes N53-1 and EGD-e, causing morphometric alterations, cell aggregation, strong deformation and cell disruption. PgTeL inhibited biofilm formation by EGD-e and N53-1 and also interfered with the adhesion and invasion processes of EGD-e and N53-1 in HeLa cells. Finally, the chitinase activity of L. monocytogenes EGD-e was reduced in the presence of PgTeL, which can be involved in the inhibition of adhesion process. CONCLUSION: PgTeL is an antibacterial agent against L. monocytogenes, inhibiting growth and promoting cell death, as well as impairing biofilm formation and bacterial adhesion and invasion into human cells. SIGNIFICANCE AND IMPACT OF THE STUDY: The results stimulate future investigations on the potential of PgTeL for protection of contamination in food products.
Asunto(s)
Antibacterianos/farmacología , Lectinas/farmacología , Listeria monocytogenes/efectos de los fármacos , Granada (Fruta) , Adhesión Bacteriana/efectos de los fármacos , Biopelículas/efectos de los fármacos , Células HeLa , Humanos , Listeria monocytogenes/fisiologíaRESUMEN
In this paper, we report our experimental design in searching a smart and easy-to-read dosimeter used to detect 6 MV X-rays for improving patient safety in radiation oncology. The device was based on an organic emissive solutions of poly(2-methoxy-5(2'-ethylhexyloxy)-p-phenylenevinylene) (MEH-PPV), aluminum-tris-(8-hydroxyquinoline) (Alq3) and additive components which were characterized by UV-Vis absorption, photoluminescence and CIE color coordinate diagram. The optical properties of MEH-PPV/Alq3 solutions have been examined as function of radiation dose over the range of 0-100 Gy. It has shown that MEH-PPV/Alq3 solutions are specifically sensitive to X-rays, since the effect of radiation on this organic system is strongly correlated with the efficient spectral overlap between Alq3 emission and the absorption of degraded MEH-PPV, which alters the color and photoemission of MEH-PPV/Alq3 mixtures from red to yellow, and then to green. The rate of this change is more sensitive when MEH-PPV/Alq3 is irradiated in the presence of benzoyl peroxide than when in the presence of hindered phenolic stabilizers, respectively, an accelerator and an inhibitor to activate or inhibit free radical formation. This gives rise to optimize the response curve of the dosimeter. It is clear from the experimental results that organic emissive semiconductors have potential to be used as dedicated and low-cost dosimeters to provide an independent check of beam output of a linear accelerator and therefore to give patients the opportunity to have information on the dose prescription or equipment-related problems a few minutes before being exposed to radiation.
Asunto(s)
Accidentes , Compuestos Organometálicos/química , Polímeros/química , Traumatismos por Radiación/prevención & control , Oncología por Radiación/instrumentación , Radiometría/instrumentación , Compuestos de Vinilo/química , Peróxido de Benzoílo/química , Humanos , Fenómenos Ópticos , Fenoles/química , Dosis de Radiación , Oncología por Radiación/economía , Radiometría/economía , Riesgo , Rayos X/efectos adversosRESUMEN
Optical absorption and fluorescence measurements have been done on poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene]/[aluminum-tris(8-hydroxyquinoline)] solutions. The authors show that there is a visible response that covers the electronic absorption of bilirubin (350-500 nm), and hence, this material is applicable for managing the radiation doses planning before treatment of jaundice of neonates, which is one of the most common reasons of hospital readmission of newborns infants. The results show that the material presents a gradation of color from orange to yellow clearly, while its peak position emission shifts from orange-red (lambda(max) = 571 nm) to green (lambda(max) = 540 nm) with the radiation exposure time. The rate of these changes can be altered by manipulations of organic solution concentration and they are usually slow (from 2 to 8 h), suggesting these color and emission changes can be used to design an easy to make, easy to read, easy to operate, low cost (< US $0.50) and accuracy for individual monitoring indicator dosimeter in order to represent easily the radiation exposure time usually used in management of neonatal jaundice.