RESUMO
The influence of lignin, lignin model compounds, and black liquor from the kraft pulping process on the hydrolysis of xylan by xylanase was investigated. Addition of vanillic acid, acetovanillone, and protocatechuic acid increased the rate of hydrolysis of xylan by as much as 18-50% at low concentrations, but reached maxima at about 0.05% concentration. Addition of vanillin caused a 15% improvement in xylan hydrolysis, while addition of guaiacol more than doubled the hydrolysis rate. Increasing concentrations of either lignin or black liquor also increased the hydrolysis rate of xylan. Circular dichroism spectroscopy indicated a change in the structure of xylanase in the presence of black liquor.
Assuntos
Lignina/metabolismo , Lignina/farmacologia , Xilanos/metabolismo , Xilosidases/metabolismo , Biodegradação Ambiental , Biotecnologia/métodos , Dicroísmo Circular , Ativação Enzimática/efeitos dos fármacos , Hidrólise/efeitos dos fármacos , PapelRESUMO
The purpose of this prospective randomized controlled clinical trial was to determine whether prophylactic antibiotics reduce the incidence of endomyometritis after forceps delivery. Of the 393 patients studied, 192 received 2 gm of intravenous cefotetan after forceps delivery, and 201 patients received no antibiotics. There were seven cases of endomyometritis in the group given no antibiotic and none in the cefotetan group, a statistically significant difference (P less than .01). We conclude that prophylactic antibiotics are effective in reducing the incidence of endomyometritis after forceps delivery. We believe this is the first published study demonstrating this benefit.
