A novel family VII esterase with industrial potential from compost metagenomic library

<p>Abstract</p> <p>Background</p> <p>Among the vast microbial genomic resources now available, most microbes are unculturable in the laboratory. A culture-independent metagenomic approach is a novel technique that circumvents this culture limitation. For the screening of novel lipolytic enzymes, a metagenomic library was constructed from compost, and the clone of <it>estCS2 </it>was selected for lipolytic properties on a tributyrin-containing medium.</p> <p>Results</p> <p>The <it>estCS2 </it>sequence encodes a protein of 570 amino acid residues, with a predicted molecular mass of 63 kDa, and based on amino acid identity it most closely matches (45%) the carboxylesterase from <it>Haliangium ochraceum </it>DSM 14365. EstCS2 belong to family VII, according to the lipolytic enzyme classification proposed by Arpigny and Jaeger, and it retains the catalytic triad Ser₂₄₅-Glu₃₆₃-His₄₆₆that is typical of an α/β hydrolase. The Ser₂₄₅residue in the catalytic triad of EstCS2 is located in the consensus active site motif GXSXG. The EstCS2 exhibits strong activity toward <it>p</it>-nitrophenyl caproate (C6), and it is stable up to 60°C with an optimal enzymatic activity at 55°C. The maximal activity is observed at pH 9, and it remains active between pH 6-10. EstCS2 shows remarkable stability in up to 50% (v/v) dimethyl sulfoxide (DMSO) or dimethylformamide (DMF). The enzyme has the ability to cleave sterically hindered esters of tertiary alcohol, as well as to degrade polyurethanes, which are widely used in various industries.</p> <p>Conclusions</p> <p>The high stability of EstCS2 in organic solvents and its activity towards esters of ketoprofen and tertiary alcohols, and in polyurethane suggests that it has potential uses for many applications in biotransformation and bioremediation.</p

Machine Learning-Aided Cooperative Localization under Dense Urban Environment

Future wireless network technology provides automobiles with the connectivity feature to consolidate the concept of vehicular networks that collaborate on conducting cooperative driving tasks. The full potential of connected vehicles, which promises road safety and quality driving experience, can be leveraged if machine learning models guarantee the robustness in performing core functions including localization and controls. Location awareness, in particular, lends itself to the deployment of location-specific services and the improvement of the operation performance. The localization entails direct communication to the network infrastructure, and the resulting centralized positioning solutions readily become intractable as the network scales up. As an alternative to the centralized solutions, this article addresses decentralized principle of vehicular localization reinforced by machine learning techniques in dense urban environments with frequent inaccessibility to reliable measurement. As such, the collaboration of multiple vehicles enhances the positioning performance of machine learning approaches. A virtual testbed is developed to validate this machine learning model for real-map vehicular networks. Numerical results demonstrate universal feasibility of cooperative localization, in particular, for dense urban area configurations

THE EFFECTS OF WHEELCHAIR CAMBER AND HANDRIM SIZE IN WHEELCHAIR BASKETBALL MOVEMENT

Improving the wheelchair design can be an important determinant of high performance in the wheelchair basketball. Researchers have focused on increasing the efficiency of the wheelchair, looking at the factors such as the seat position, handrim size, and wheel camber. Most handrim and wheel chamber studies, however, have focused only on the propulsive phase. Quick turn as well as fast propulsion is essential to the success in a wheelchair basketball game and the energy efficiency becomes particularly important in a prolonged wheelchair use. The purpose of this study was to investigate the effects of wheelchair camber and handrim size on the linear propulsion, turn velocity, and efficiency

Prospective Multi-Center Trial for the Efficacy of Ecabet Sodium on the Relief of Dyspepsia in Korean Patients with Chronic Gastritis

Anti-peptic and anti-inflammatory actions of ecabet sodium might be beneficial in either improving gastritis or relieving dyspeptic symptoms. This study was designed to evaluate the clinical efficacy of ecabet sodium on dyspeptic symptoms and to elucidate the molecular mechanism attributable to symptom relief in patients with chronic gastritis. Two hundred and sixty eight chronic gastritis patients with persistent dyspepsia received ecabet sodium 1 g b.i.d. for 2 weeks, after which dyspeptic symptoms were reassessed with a questionnaires as before. The changes of interleukin-8 (IL-8), inducible nitric oxide synthase (iNOS), prostaglandin E2 (PGE2), and vascular endothelial growth factor (VEGF) levels in gastric juices were measured by ELISA. The changes of nitrotyrosine in gastric mucosa were measured by immunohistochemical staining. The most common dyspeptic symptom in Korean patients with chronic gastritis was epigastric soreness (76.8%), which was improved significantly after ecabet sodium treatment (81.7%, p<0.001). Ecabet sodium was more effective in patients with epigastric pain than vague abdominal discomfort (p = 0.02), especially in patients with old age. Complete relief of discomfort was more highly achieved in patients with positive Helicobacter pylori than without (p = 0.01). In spite of clear tendency that the decreased levels of IL-8, iNOS, and PGE2 and increased levels of VEGF were measured in gastric juices after ecabet sodium treatment, no statistical significance was noted, which might be due to high inter-individual variations. The nitrotyrosine expressions were significantly decreased after ecabet sodium treatment than before (p<0.01). In conclusion, ecabet sodium treatment was very useful for the relief of dyspeptic symptoms in chronic gastritis, to which both attenuated inflammatory and enhanced regenerative mechanisms were contributive

An optical-frequency synthesizer using integrated photonics

Optical-frequency synthesizers, which generate frequency-stable light from a single microwave-frequency reference, are revolutionizing ultrafast science and metrology, but their size, power requirement and cost need to be reduced if they are to be more widely used. Integrated-photonics microchips can be used in high-coherence applications, such as data transmission, highly optimized physical sensors and harnessing quantum states, to lower cost and increase efficiency and portability. Here we describe a method for synthesizing the absolute frequency of a lightwave signal, using integrated photonics to create a phase-coherent microwave-to-optical link. We use a heterogeneously integrated iii–v/silicon tunable laser, which is guided by nonlinear frequency combs fabricated on separate silicon chips and pumped by off-chip lasers. The laser frequency output of our optical-frequency synthesizer can be programmed by a microwave clock across 4 terahertz near 1,550 nanometres (the telecommunications C-band) with 1 hertz resolution. Our measurements verify that the output of the synthesizer is exceptionally stable across this region (synthesis error of 7.7 × 10^(−15) or below). Any application of an optical-frequency source could benefit from the high-precision optical synthesis presented here. Leveraging high-volume semiconductor processing built around advanced materials could allow such low-cost, low-power and compact integrated-photonics devices to be widely used

Get Ready for 100 Years of Active Spine Life Using Percutaneous Endoscopic Spine Surgery (PESS)

Lumbar spinal stenosis is the most common indication for spinal surgery in patients older than 65 years. After the introduction of Kambin's safety triangle, percutaneous endoscopic spine surgery has started through transforaminal approach for discectomy and is now being extended to spinal stenosis through interlaminar approach, which is an important part of the degenerative spinal disease. With the increase in human longevity, the development of effective treatment for degenerative diseases is inevitable, and future percutaneous endoscopic spine surgery (PESS) will play a very important role in maintaining the health of this ‘super-aged’ population. Endoscopic techniques impart minimal approach related disruption of normal spinal anatomy and function while concomitantly increasing functional visualization and correction of degenerative stenosis. Advantages of full endoscopic spine surgeries are less soft tissue dissection, less blood loss, reduced hospital admission days, early functional recovery and enhancement in the quality of life. With proper training and advancement in equipment and technologies, percutaneous endoscopic spine surgery will be able to successfully treat the aging spine