The degradation of 2,6-dimethoxyphenol (DMP) and decolorization of Remazol brilliant blue R dye (RBB), added to culture media of Pleurotus ostreatus developed in submerged fermentation, and the laccase, manganese peroxidase and veratryl alcohol oxidase activities produced in these systems were evaluated. Both compounds were removed from the culture medium mainly by enzymatic action. These compounds decreased the specific growth rate and the effect on the maximal biomass values was not important. The enzymatic activities were increased by DMP and/or RBB; however, the DMP showed a higher inducer effect on all enzymes than RBB. On the other hand, the RBB showed a larger inducer effect on manganese peroxidase activity than on the laccases and veratryl alcohol oxidase activities. These results show that DMP was a better inducer of ligninolytic enzymes than dye, and the process of dye decolorization and degradation of DMP requires the action of all enzymes of the ligninolytic complex.

No abstract

Infections caused by the human immunodeficiency virus (HIV) and human papillomavirus (HPV) cause thousands of deaths worldwide each year. So far, there has been no consensus on whether there is a direct relationship between the incidence of neoplasms and the immunosuppression caused by HIV that could help understand if coinfection increases the likelihood of cervical cancer. The objective of the study was to identify the presence of genetic variants of HPV in a group of HIV-positive women and their possible association with cervical cancer. Cervical samples were taken from HIV-positive patients for cytological analysis to identify the HPV genotype by polymerase chain reaction (PCR) and sequencing. The most preva¬lent L1 capsid protein mutations in the HPV genotype were ana¬lyzed in silico. Various types of HPV were identified, both high-risk (HR) and low-risk (LR). The most prevalent genotype was HPV51. Analysis of the L1 gene sequences of HPV51 isolates showed nucleo¬tide variations. Of the samples analyzed in Puebla, Mexico, HPV51 had the highest incidence (17.5%, 7/40). Different mutations, which could be used as population markers, were detected in this area, and they have not been reported in the L1 databases for HPV51 in Mexico. Genotypes 6, 14, 86, 87, 89, and 91, not detected or reported in samples from patients with HPV in Mexico, were also identified. Data from the population analyzed suggest no direct relationship between HIV immunosuppression and cervical cancer, regardless of the high- or low-risk HPV genotype. Furthermore, it is possible to develop regional population markers for the detection of HPV based on the mutations that occur in the sequence of nucleotides analyzed.

The heterologous expression of the gene LACP83 (encoding a laccase) from Pleurotus ostreatus in Escherichia coli was characterized. The laccase enzyme activity and kinetics of bacterial growth with an inducer (IPTG) and without inducer were determined. The maximum enzymatic activity was observed at 7 h post induction with a value of 3740 ± 342 U/L, which was similar to that reported for the native strain of P. ostreatus at 144 h of culture. Furthermore, the induction of laccase with IPTG reduced the specific growth rate of recombinant E. coli BL21 by approximately 50%. These results support the use this system for the recombinant production of the enzyme on an industrial scale.

Antecedentes: Lentinula edodes es un hongo comestible de importancia económica en México, produce un compuesto reductor de colesterol llamado eritadenina, el cual se ha obtenido del cuerpo fructífero y micelio del hongo. Su producción se ha evaluado en fermentación sumergida, pero hasta ahora no se ha evaluado la fermentación en estado sólido. Objetivos: Determinar si la fermentación en estado sólido de L. edodes mejora la producción de eritadenina. Métodos: Se realizó una fermentación en estado sólido con espuma de poliuretano y un medio enriquecido para determinar la producción de eritadenina, biomasa y consumo de sustrato; la eritadenina se detectó por HPLC-DAD a 260 nm. Resultados y conclusiones: La biomasa máxima fue de 3.6 ± 0.11 g/L, con una tasa de crecimiento específico de 0.015 ± 0.002 h-1. La eritadenina se produjo en la biomasa y se liberó al medio de cultivo; a las 168 h de incubación se incrementó 2.8 y 2.4 veces, respectivamente. Se encontró una relación proporcional entre la producción de eritadenina y biomasa. No hubo relación entre el consumo de sustrato y la producción de eritadenina. La fermentación en estado sólido es una alternativa para producir y recuperar la eritadenina.