Abstract In this work, we studied 46 bacterial isolates to determine their potential for polyethylene terephthalate (PET) degradation. Only eight lipase-positive isolates were pre-selected to continue analysis. The isolates belonged to the genera Micrococcus, Acinetobacter, Pseudomonas, Bacillus, and Pseudochrobactrum. In addition to lipase, other enzymatic activities such as protease, carboxymethyl cellulase, xylanase, and chitinase were detected. PET sheets were pretreated with temperature, UV light, HNO3, and Stenotrophomonas pavanii. All isolates were tested against pretreated PET for 60 days. All isolates displayed lipase activity, and some hydrolase activities. The chemical changes of PET sheets were determined using Fourier-transform infrared spectroscopy. Peaks observed at 3000-3500 cm-1 corresponding to hydroxyl group suggested degradation. The physical changes of PET observed with the naked eye and with SEM consisted of erosion, bubbles, scales, bumps, pits, and a shiny surface. Pseudomonas soli was selected as the best PET degrader, according to the notable changes in the infrared spectrum and macroscopic changes compared to the other genera and the control. In addition, this isolate did not show xylanase activity and it lacks the chitinase gene too. It is possible that not only lipase activity could be associated with the PET degradation, but also another enzymatic activity not detected in this study. Although the genus Pseudomonas has been reported as a plastic degrader, the P. soli species is novel in the degradation of PET, as well as the other genera mentioned here. Finally, these findings contribute to the knowledge of bacterial species for PET degradation. work 4 (PET lipasepositive positive preselected pre analysis Micrococcus Acinetobacter Bacillus Pseudochrobactrum protease cellulase temperature light HNO3 HNO pavanii 6 days Fouriertransform Fourier transform spectroscopy 30003500 3000 3500 3000-350 cm1 cm 1 cm- erosion bubbles scales bumps pits surface degrader control too study P here Finally 3000350 300 350 3000-35 300035 30 35 3000-3 30003 3 3000-

ABSTRACT Artemisia ludoviciana contains several medically important metabolites, but few studies have been reported on its effects on insects of agricultural importance. This article aimed to know the biological effects of a methanolic extract of A. ludoviciana on neonatal larvae of Spodoptera frugiperda, where column chromatography was obtained to fractionate the crude oil and mass gas chromatography to identify metabolites, the extract, and the 90:10 mobile phase showed low mortality of about 30% at a concentration of 1 mg/mL, but a weight loss in neonatal larvae of more than 50% was lost, confirming a significant antifeedant activity. GC-MS analysis revealed the presence of terpenoids such as limonene, thujone, camphor, borneol, and borneol acetate, which are associated with an insecticidal and antifeedant activity. Therefore, the methanolic extracts of A. ludoviciana can be a friendly alternative for insect pest control.

RESUMEN Artemisia ludoviciana contiene varios metabolitos de importancia médica, sin embargo, se han informado pocos estudios sobre sus efectos en insectos de importancia agrícola. El objetivo de este trabajo fue conocer los efectos biológicos de un extracto metanólico de A. ludoviciana sobre larvas neonatas de Spodoptera frugiperda en donde se utilizó cromatografía de columna para fraccionar el crudo y cromatografía de gases masas para identificación de metabolitos, dando como resultados que el extracto y la fase móvil 90:10 mostraron una baja mortalidad de alrededor del 30 % a una concentración de 1 mg/mL, sin embargo, se observó una pérdida de peso en las larvas neonatas de más de 50 %, corroborando una actividad antialimentaria significativa, y el análisis GC-MS reveló la presencia de terpenoides como: limoneno, tujona, alcanfor, borneol y acetato de borneol, asociados con el efecto insecticida y la actividad antialimentaria. Por lo tanto, los extractos metanólicos de A. ludoviciana, pueden ser una alternativa amigable para el control de insectos plagas.

Abstract Beauveria bassiana is an entomopathogenic fungus that produces secondary metabolites as virulence factors during the pathogenic process in insects. In this study, eleven strains of B. bassiana were analyzed to determine the presence of the bbBeas and bbBsls genes that produce beauvericin and bassianolide non-ribosomal cyclooligomeric depsypeptides, respectively. The genes were characterized by PCR and DNA sequencing. The presence of beauvericin and bassianolide from mycelial extracts were determined by mass spectrometry. The results indicated that with the exception of strain 2857, they all possess both genes and synthesized bassianolide. Beauvericin was not produced in any case. Mortality caused by conidia in Spodoptera exigua and S. frugiperda neonate larvae was variable. Strains 1512, 2253 and 2857 caused significantly higher mortalities (44 % mortality on average). The bassianolide extract injected (1 mg/mL) caused 26 % mortality in S. exigua. The lack of beauvericin production, with the exception of strain 1149, may be due to the requirement of other culture conditions that stimulate the expression of the genes. So far, no correlation is observed between the pathogenic activity of the fungus, and the presence or absence of these secondary metabolites.

Resumen Beauveria bassiana es un hongo entomopatógeno que produce metabolitos secundarios como factores de virulencia durante el proceso patogénico en insectos. En este estudio se analizaron once cepas de B. bassiana para determinar la presencia de los genes bbBeas y bbBsls productores de los depsipéptidos ciclooligoméricos no ribosomales beauvericina y bassianolida, respectivamente. Los genes fueron caracterizados por PCR y secuenciación. La presencia de beauvericina y bassianolida en extractos de micelio se determinó por espectrometría de masas. Los resultados indicaron que con excepción de la cepa 2857, todas poseen los dos genes y sintetizan bassianolida. En ningún caso se produjo la beauvericina. La mortalidad por conidias en larvas de Spodoptera exigua y S. frugiperda fue variable, pero las cepas 1512, 2253 y 2857 causaron las mayores mortalidades (44 % en promedio). El extracto con bassianolida inyectado (1 mg/mL) causó 26 % de mortalidad en larvas de S. exigua. La falta de producción de beauvericina, con excepción de la cepa 1149, puede deberse al requerimiento de otro tipo de condiciones de cultivo que estimulen la expresión de los genes. Hasta ahora no se observa correlación entre la actividad patogénica del hongo y la presencia o ausencia de estos metabolitos secundarios.

Abstract In the present study, the microbial diversity was analyzed in agricultural soils from Río Bravo city and Cuauhtémoc Station, Tamp., and the surroundings of the city of Dolores Hidalgo, Guanajuato. Microorganisms isolation and tolerance tests were conducted preselectively using 2,4-D and malathion. Microbial identification was conducted by 16S gen amplification in bacteria and ITS region in fungi. The bacterial genus Pseudomonas, and the fungal genus Penicillium were the most abundant in the analyzed samples. Pseudomonas aeruginosa, Stenotrophomonas pavanii and Acinetobacter lactucae grew at a concentration> 2.0 g L-1 of 2,4-D and > 1.0 g L-1 of malathion. Fusarium sp. grew at 2.0 g L-1 of malathion and 0.9 g L-1 of 2,4-D herbicide, and Talaromyces variabilis tolerated up to 3.1 g L-1 of malathion. There are no reports of tolerance for S. pavanii, A. Lactucae, and T. variabilis to these pesticides so far. Therefore, the semicroorganisms may have the potential to be used in soil bioremediation techniques.

Resumen En el presente estudio, se analizó la diversidad microbiana de los suelos agrícolas de las localidades de Río Bravo y la Estación Cuauhtémoc en el estado de Tamaulipas y en los límites de Dolores Hidalgo en el estado de Guanajuato. Los plaguicidas utilizados fueron 2,4-D y malatión, con los que se establecieron pruebas preselectivas para el aislamiento de los microorganismos y su tolerancia. Para la identificación de las bacterias se amplificó el gen 16S y para los hongos la región ITS. El género bacteriano Pseudomonas, así como el género fúngico Penicillium fueron los de mayor abundancia en las muestras analizadas. Los resultados indicaron que las cepas tolerantes fueron Pseudomonas aeruginosa, Stenotrophomonas pavanii y Acinetobacter lactucae creciendo a una concentración > 2.0 g L-1 de 2,4-D y > 1.0 g L-1 de malatión. Así como Fusarium sp., a 2.0 g L-1 de malatión y 0.9 g L-1 de 2,4-D y el hongo Talaromyces variabilis con un crecimiento a 3.1 g L-1 de malatión. Para el caso de S. pavanii, A. Lactucae y T. variabilis no existen reportes de tolerancia a los plaguicidas mencionados, sin embargo, en este trabajo se demuestra por primera vez que pueden ser utilizados en técnicas de biorremediación de suelos.