Bioprospecting of Native Efflux Pumps To Enhance Furfural Tolerance in Ethanologenic Escherichia coli.

Efficient microbial conversion of lignocellulose into valuable products is often hindered by the presence of furfural, a dehydration product of pentoses in hemicellulose sugar syrups derived from woody biomass. For a cost-effective lignocellulose microbial conversion, robust biocatalysts are needed that can tolerate toxic inhibitors while maintaining optimal metabolic activities. A comprehensive plasmid-based library encoding native multidrug resistance (MDR) efflux pumps, porins, and select exporters from Escherichia coli was screened for furfural tolerance in an ethanologenic E. coli strain. Small multidrug resistance (SMR) pumps, such as SugE and MdtJI, as well as a lactate/glycolate:H+ symporter, LldP, conferred furfural tolerance in liquid culture tests. Expression of the SMR pump potentially increased furfural efflux and cellular viability upon furfural assault, suggesting novel activities for SMR pumps as furfural efflux proteins. Furthermore, induced expression of mdtJI enhanced ethanol fermentative production of LY180 in the presence of furfural or 5-hydroxymethylfurfural, further demonstrating the applications of SMR pumps. This work describes an effective approach to identify useful efflux systems with desired activities for nonnative toxic chemicals and provides a platform to further enhance furfural efflux by protein engineering and mutagenesis.IMPORTANCE Lignocellulosic biomass, especially agricultural residues, represents an important potential feedstock for microbial production of renewable fuels and chemicals. During the deconstruction of hemicellulose by thermochemical processes, side products that inhibit cell growth and production, such as furan aldehydes, are generated, limiting cost-effective lignocellulose conversion. Here, we developed a new approach to increase cellular tolerance by expressing multidrug resistance (MDR) pumps with putative efflux activities for furan aldehydes. The developed plasmid library and screening methods may facilitate new discoveries of MDR pumps for diverse toxic chemicals important for microbial conversion.

Síndrome de Scheuthauer Marie Sainton / Scheuthauer-Marie-Sainton syndrome

RESUMEN El síndrome de Scheuthauer Marie Sainton es una enfermedad poco frecuente, que sigue un patrón de herencia autosómico dominante con expresividad variable. Se presenta paciente masculino de 74 años de edad, nacido por parto distócico (cesárea) producto a una desproporción cefalopélvica materna. Acudió a la consulta de Medicina General Integral, del Policlínico Docente "Efraín Mayor Amaro", municipio Cotorro, La Habana, con tos y secreción nasal. Se interpretó como un catarro común para lo cual se le indicó abundantes líquidos, analgésicos, antihistamínicos y vitamina C. En el examen físico se constató que el paciente padecía del síndrome de Scheuthauer Marie Sainton, pues tenía ausencia de ambas clavículas, deformidades óseas y anomalías dentales; además, se detectó tórax acampanado, el cual es evidente en el período de recién nacido. Para el tratamiento de esta enfermedad, el paciente fue remitido a la consulta de estomatología. Desde el punto de vista óseo, no se realizó ninguna cirugía correctora a voluntad del paciente(AU)

ABSTRACT Scheuthauer Marie Sainton syndrome is a rare disease that follows an autosomal dominant pattern of inheritance with variable expressivity. We report a case of a 74-year-old male patient, who was born by dystocic delivery (cesarean section) due to maternal cephalopelvic disproportion. He went to the Comprehensive General Medicine consultation at Efraín Mayor Amaro Teaching Community Clinic, Cotorro municipality, Havana, with a cough and runny nose. It was interpreted as a common cold and he was prescribed abundant fluids, analgesics, antihistamines and vitamin C. On physical examination it was found that the patient suffered from Scheuthauer Marie Sainton syndrome, as he had absence of both clavicles, bone deformities and dental abnormalities. In addition, he was noticed to have flared chest, which is evident in the newborn period. The patient was referred to the stomatology consultation for the treatment of this disease. No corrective bone surgery was performed at the patient's discretion(AU)

RÉSUMÉ Le syndrome de Scheuthauer-Marie-Sainton est une maladie peu fréquente, qui suit un modèle de transmission autosomique dominante à expression variable. Un patient âgé de 74 ans, né par accouchement dystocique (césarienne) dû à une disproportion céphalo-pelvienne maternelle, est présenté. Du fait de la toux et des sécrétions nasales, il est allé à la consultation de médecine générale intégrale, de la polyclinique universitaire Efrain Mayor Amaro, dans la municipalité de Cotorro, à La Havane. Un rhume a été considéré, c'est pourquoi on lui a indiqué de prendre des boissons en abondance, et prescrit des analgésiques, des antihistaminiques et de la vitamine C. Dans l'examen physique, on a pu constater que le patient était atteint de syndrome de Scheuthauer-Marie-Sainton, caractérisé par l'absence complète des clavicules, des difformités osseuses et des anomalies de la denture ; on a aussi trouvé un thorax évasé, très évident chez le nouveau-né. Pour le traitement de cette maladie, le patient a été dirigé à la consultation de stomatologie. Du point de vue osseux, aucune chirurgie de correction n'a été effectuée en respectant la volonté du patient(AU)