Extracellular tyrosol and tryptophol were produced and isolated from the phytopathogen fungus Ceratocystis adiposa cultivated in a rich broth. These compounds have not been previously reported in this Ceratocystis species, as its identification was established through spectroscopic methods ( 1 H NMR, 13 C NMR and MS). Productivity of tyrosol and tryptophol was 65.3 and 44 lg l -1 day -1 , respectively, which were values higher than those reported to date. Tyrosol is a compound of pharmaceutical interest showing antioxidating activity, a property used in the treatment of atherosclerosis. Tryptophol is reported to have antibiotic and phytotoxic activity.

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Los manglares son uno de los tipos de humedales costeros presentes en la cuenca baja del río Coatzacoalcos que, a pesar de su creciente deterioro, conservan importancia ecológica y económica. El objetivo del presente estudio fué identificar la principal actividad antropogénica que ha contribuído a reducir la cobertura de manglar en la cuenca baja del río Coatzacoalcos, mediante dos métodos: 1) comparando las áreas de los manglares y el desarrollo urbano, entre los años 1986 y 2016, con imágenes Landsat y Sentinel (escala 1:250,000), utilizando Q-Gis versión 2.14.2; y 2) mediante una matriz de máximos y mínimos, donde se asignaron valores para calificar el grado de afectación de las acciones antrópicas a cada componente del ecosistema. De acuerdo con el análisis espacial realizado, entre 1986 y 2016, se registró una pérdida del 86% de manglares, asociado al aumento de los asentamientos humanos en la cuenca baja del río Coatzacoalcos. Las acciones que más afectaron los componentes ambientales fueron los asentamientos humanos, desmontes y rellenos, ganadería y emplazamientos industriales con porcentajes de afectación de 15.9, 15.7, 15.5 y 13.5%, respectivamente. Los componentes ambientales más afectados fueron el suelo, la flora y el agua, con porcentajes de afectación del recurso de 17, 17 y 16%, respectivamente. Los asentamientos humanos son la principal causa de pérdida de manglares en la cuenca baja del río Coatzacoalcos, en particular los asentamientos irregulares que se dan en la región.

Eighteen lactic acid bacteria (LAB) strains, isolated from coffee pulp silages were characterized according to both growth and gallic acid (GA) consumption. Prussian blue method was adapted to 96-well microplates to quantify GA in LAB microcultures. Normalized data of growth and GA consumption were used to characterize strains into four phenotypes. A number of 5 LAB strains showed more than 60% of tolerance to GA at 2 g/l; whereas at 10 g/l GA growth inhibition was detected to a different extent depending on each strain, although GA consumption was observed in seven studied strains (>60%). Lactobacillus plantarum L-08 was selected for further studies based on its capacity to degrade GA at 10 g/l (97%). MRS broth and GA concentrations were varied to study the effect on growth of LAB. Cell density and growth rate were optimized by response surface methodology and kinetic analysis. Maximum growth was attained after 7.5 h of cultivation, with a dilution factor of 1-1/2 and a GA concentration between 0.625 and 2.5 g/l. Results indicated that the main factor affecting LAB growth was GA concentration. The main contribution of this study was to propose a novel adaptation of a methodology to characterize and select LAB strains with detoxifying potential of simple phenolics based on GA consumption and tolerance. In addition, the methodology presented in this study integrated the well-known RSM with an experimental design based on successive dilutions.

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Contamination of soil with petroleum is common in oil-producing areas across the tropical regions of the world. There is limited knowledge on the sensitivity of endogeic tropical earthworms to the contamination of soil with total petroleum hydrocarbons (TPH) present in crude oil. Pontoscolex corethrurus is a dominant species in tropical agroecosystems around oil-processing facilities. The sensitivity of P. corethrurus to soil artificially contaminated with "Maya" Mexican heavy crude oil was investigated through avoidance and acute ecotoxicity tests, using the following measured concentrations: 0 (reference soil), 551, 969, 4845, 9991 and 14,869 mg/kg. The avoidance test showed that P. corethrurus displayed a significant avoidance behavior to heavy crude oil at a concentration of 9991 mg/kg or higher. In contrast, acute toxicity tests indicate that the median lethal concentration (LC) was 3067.32 mg/kg; however, growth (weight loss) was more sensitive than mortality. Our study revealed that P. corethrurus is sensitive to TPH, thus highlighting the importance of P. corethrurus for petroleum ecotoxicological tests.

No abstract

Meloidogyne incognita root-knot nematode is one of the main causes of tomato root damage and consequently crop production losses. Thus, in in vitro conditions, the number of nematodes hatched eggs (%) at 4 and 6 days and nematode mortality (J2 stage) at 8, 18, and 24 h, were evaluated in Petri dishes containing the candidate rhizobacteria Enterobacter asburiae (BA4-19 and PM3-14), Acinetobacter calcoaceticus (BM2-12), Klebsiella variicola (BO3-4) and Serratia marcescens (PM3-8). The well-known Pseudomonas protegens (CHA0) and P. veronii (R4) were used as controls. In greenhouse conditions, plant height, root weight, and symptoms, as well as gall and nematode numbers, were determined in tomato plants infected by M. incognita and treated with the seven rhizobacteria. In addition, all variables were correlated using Pearson's analysis. In general, a significant correlation was observed among the variables of both experiments, showing the antagonistic capacity of the strains against nematode. It seems, that PM3-8 and PM3-14 strains reduce hatching, and cause mortality of nematodes J2 if compared with CHA0 and R4 strains. Likewise, tomato treated with BM2-12 strain shows a higher height and root weight, as well as a smaller number of galls and nematodes in their roots. This study provides evidence that PM3-8 and PM3-14 strains reduce the M. incognita egg hatching, and that the BM2-12 strain can be a plant growth-promoter potential of tomato plants.