The abilities of enzymes to catalyze reactions in nonnatural environments of organic solvents have opened new opportunities for enzyme-based industrial processes. However, the main drawback of such processes is that most enzymes have a limited stability in polar organic solvents. In this study, we employed protein engineering methods to generate a lipase for enhanced stability in methanol, which is important for biodiesel production. Two protein engineering approaches, random mutagenesis (error-prone PCR) and structure-guided consensus, were applied in parallel on an unexplored lipase gene from Geobacillus stearothermophilus T6. A high-throughput colorimetric screening assay was used to evaluate lipase activity after an incubation period in high methanol concentrations. Both protein engineering approaches were successful in producing variants with elevated half-life values in 70% methanol. The best variant of the random mutagenesis library, Q185L, exhibited 23-fold-improved stability, yet its methanolysis activity was decreased by one-half compared to the wild type. The best variant from the consensus library, H86Y/ A269T, exhibited 66-fold-improved stability in methanol along with elevated thermostability (؉4.3°C) and a 2-fold-higher fatty acid methyl ester yield from soybean oil. Based on in silico modeling, we suggest that the Q185L substitution facilitates a closed lid conformation that limits access for both the methanol and substrate excess into the active site. The enhanced stability of H86Y/A269T was a result of formation of new hydrogen bonds. These improved characteristics make this variant a potential biocatalyst for biodiesel production.

These favourable results, despite the short half-life of this compound in vivo, support further studies of controlled sustained release or more prolonged administration of allicin as a treatment for aspergillosis.

Traumatic injury to the extrahepatic biliary system is rare and usually diagnosed at laparotomy when it is associated with other visceral injuries. Isolated gallbladder rupture due to blunt abdominal trauma is even rarer. The clinical presentation of gallbladder injury is variable, resulting in a delay in diagnosis and treatment. Awareness to the possibilty of trauma to the extrahepatic biliary system enables early surgical intervention and eliminates the high morbidity associated with delated diagnosis. A 5 year old child with isolated gallbladder rupture caused by blunt abdominal trauma is presented.

The efficiency and safety of the 2 most commonly used endoscopic dilators, Savary-Gilliard and pressure balloons, were compared in 2 groups, each including 30 patients, with benign esophageal strictures. Four additional patients with tight and tortuous cervical esophageal strictures were initially managed by balloon dilatation followed by Savary-Gilliard dilatation. These patients could not be dilated by each of the methods alone. Sixty patients [35 males and 25 females with a mean age of 52 years (range, 4-91)] underwent 165 esophageal dilatations. The etiologies of strictures included reflux esophagitis (65%), caustic damage (18.3%), and postoperative (anastomotic, or post-Nissen operation) in 16.7%. Dysphagia improved in all patients; however, 2 patients (1 from each group) with hard postoperative anastomotic stricture eventually underwent surgical resection of stricture. There were no major complications or mortality related to the dilatations. Both methods were highly effective and well tolerated, yet Savary-Gilliard dilators were slightly more effective and simpler to use than balloons. Nevertheless, tortuous cervical strictures and multiple closely-placed strictures were more effectively managed by initial use of balloon followed by Savary dilators.