Role of the ArcAB two-component system in the resistance of Escherichia coli to reactive oxygen stress

<p>Abstract</p> <p>Background</p> <p>The global regulatory system ArcAB controls the anaerobic growth of <it>E. coli</it>, however, its role in aerobic conditions is not well characterized. We have previously reported that ArcA was necessary for <it>Salmonella </it>to resist reactive oxygen species (ROS) in aerobic conditions.</p> <p>Results</p> <p>To investigate the mechanism of ROS resistance mediated by ArcAB, we generated deletion mutants of ArcA and ArcB in <it>E. coli</it>. Our results demonstrated that both ArcA and ArcB were necessary for resistance to hydrogen peroxide (H₂O₂), a type of ROS, and their function in this resistance was independent from H₂O₂scavenge. Mutagenesis analysis of ArcA indicated that ROS resistance was mediated through a distinct signaling pathway from that used in anaerobic conditions. An abundant protein flagellin was elevated at both the protein and mRNA levels in the <it>ΔarcA </it>mutant as compared to the wild type <it>E. coli</it>, and deletion of flagellin restored the resistance of the <it>ΔarcA </it>mutant to H₂O₂. The resistance of the <it>ΔarcA </it>mutant <it>E. coli </it>to H₂O₂can also be restored by amino acid supplementation, suggesting that a deficiency in amino acid and/or protein synthesis in the mutant contributed to its susceptibility to H₂O₂, which is consistent with the notion that protein synthesis is necessary for ROS resistance.</p> <p>Conclusion</p> <p>Our results suggest that in addition to its role as a global regulator for anaerobic growth of bacteria, ArcAB system is also important for bacterial resistance to ROS in aerobic conditions, possibly through its influence on bacterial metabolism, especially amino acid and/or protein assimilation and synthesis.</p

IMPLIKASI ARTIFICIAL INTELLIGENCE TERHADAP PELAYANAN BANTUAN HUKUM BAGI PENYANDANG DISABILITAS

Bangsa Indonesia saat ini berada dalam krisis penegakan hukum. Dalam praktiknya, aparat penegak hukum cenderung mengabaikan hingga menganut ketidakpedulian terhadap keadilan hukum yang  menimbulkan penurunan kepercayaan masyarakat terhadap aparat penegak hukum. Adapun kelompok yang paling rentan mengalami ketidakadilan akibat krisis penegakan hukum adalah masyarakat penyandang disabilitas. Pada dasarnya ketidaksempurnaan itu tidak boleh menjadi penyebab hilangnya harkat dan martabat masyarakat penyandang disabilitas. Adapun terdapat urgensi penelitian ini yakni dikarenakan adanya terdapat krisis penegakan hukum sehinggadalam mencegah terjadinya pengabaian hak yang mengarah kepada diskriminatif bagi masyarakat penyandang disabilitas didalam praktik penegakan hukum diperlukan pembahasan mengenai pemanfaatan Artificial Intelligence (AI) bagi  masyarakat penyandang disabilitas menjadi hal yang penting dan aktual untuk dilakukan pengkajian lebih lanjut. Penelitian ini berfokus kepada pemanfaatan Artificial Intelligence (AI) sebagai alat bantu pemberian bantuan hukum bagi masyarakat penyandang disabilitas agar tercapainya penegakan hukum yang memenuhi nilai keadilan, nilai kepastian dan nilai kemanfaatan. Spesifikasi dalam penelitian ini menggunakan jenis metode penelitian yuridis normatif dengan pendekatan perundang-undangan (statute approach) dan pendekatan konseptual (conceptual approach). Data yang dianalisis yakni data sekunder yang diperoleh secara tidak langsung melalui teknik studi kepustakaan.Bangsa Indonesia saat ini berada dalam krisis penegakan hukum. Dalam praktiknya, aparat penegak hukum cenderung mengabaikan hingga menganut ketidakpedulian terhadap keadilan hukum yang  menimbulkan penurunan kepercayaan masyarakat terhadap aparat penegak hukum. Adapun kelompok yang paling rentan mengalami ketidakadilan akibat krisis penegakan hukum adalah masyarakat penyandang disabilitas. Pada dasarnya ketidaksempurnaan itu tidak boleh menjadi penyebab hilangnya harkat dan martabat masyarakat penyandang disabilitas. Adapun terdapat urgensi penelitian ini yakni dikarenakan adanya terdapat krisis penegakan hukum sehinggadalam mencegah terjadinya pengabaian hak yang mengarah kepada diskriminatif bagi masyarakat penyandang disabilitas didalam praktik penegakan hukum diperlukan pembahasan mengenai pemanfaatan Artificial Intelligence (AI) bagi  masyarakat penyandang disabilitas menjadi hal yang penting dan aktual untuk dilakukan pengkajian lebih lanjut. Penelitian ini berfokus kepada pemanfaatan Artificial Intelligence (AI) sebagai alat bantu pemberian bantuan hukum bagi masyarakat penyandang disabilitas agar tercapainya penegakan hukum yang memenuhi nilai keadilan, nilai kepastian dan nilai kemanfaatan. Spesifikasi dalam penelitian ini menggunakan jenis metode penelitian yuridis normatif dengan pendekatan perundang-undangan (statute approach) dan pendekatan konseptual (conceptual approach). Data yang dianalisis yakni data sekunder yang diperoleh secara tidak langsung melalui teknik studi kepustakaan

A Novel Indexing Method for Improving Timeliness of High-Dimensional Data

Investment in information technology (IT) has been growing rapidly and one key reason for investing in IT is to improve information quality (IQ). Timeliness is an important IQ dimension that often needs to be improved for decision making. Especially in the era of big data, timeliness becomes more valued because of challenges of massive data size and high dimensionality. Many financial analyses require timely data to support time-critical decision making. In this paper, we develop a novel index method and effective query algorithms to reduce latency of querying high-dimensional data. The effectiveness of point, range, and similarity queries implemented using our methods is evaluated using a high-dimensional testbed conducted using real world financial data. Results show that our method outperforms existing methods in query speed of three types of queries frequently used in financial decision making

Role resources and work-family enrichment: The role of work engagement

The majority of work-family research has focused on negative spillover between demands and outcomes and between the work and family domains (e.g., work-family conflict; see review by Eby, Casper, Lockwood, Bordeaux, & Brinley, 2005). The theory that guided this research was in most cases role stress theory (Greenhaus & Beutell, 1985) or the role scarcity hypothesis (Edwards & Rothbard, 2000). However, according to spillover theory, work-related activities and satisfaction also affect non-work performance, and vice versa. Recently, in line with the positive psychology movement (Seligman & Csikszentmihalyi, 2000), work-family interaction research has also included concepts of positive spillover (Bakker & Schaufeli, 2008; Grzywacz & Marks, 2000). This emerging focus supplements the dominant conflict perspective by identifying new ways of cultivating human resource strength

VolumeViewer: An Interactive Tool for Fitting Surfaces to Volume Data

Recent advances in surface reconstruction algorithms allow surfaces to be built from contours lying on non-parallel planes. Such algorithms allow users to construct surfaces of similar quality more efficiently by using a small set of oblique contours, rather than many parallel contours. However, current medical imaging systems do not provide tools for sketching contours on oblique planes. In this paper, we take the first steps towards bridging the gap between the new surface reconstruction technologies and putting those methods to use in practice. We develop a novel interface for modeling surfaces from volume data by allowing the user to sketch contours on arbitrarily oriented cross-sections of the volume, and we examine the users\u27 ability to contour the same structures using oblique cross-sections with similar consistency as they can using parallel cross-sections. We measure the inter-observer and intra-observer variability of trained physicians contouring on oblique cross-sections of real patient data as compared to the traditional parallel cross-sections, and show that the variation is much higher for oblique contouring. We then show that this variability can be greatly reduced by integrating a collection of training images into the interface

Co-expression of adjacent genes in yeast cannot be simply attributed to shared regulatory system

<p>Abstract</p> <p>Background</p> <p>Adjacent gene pairs in the yeast genome have a tendency to express concurrently. Sharing of regulatory elements within the intergenic region of those adjacent gene pairs was often considered the major mechanism responsible for such co-expression. However, it is still in debate to what extent that common transcription factors (TFs) contribute to the co-expression of adjacent genes. In order to resolve the evolutionary aspect of this issue, we investigated the conservation of adjacent pairs in five yeast species. By using the information for TF binding sites in promoter regions available from the MYBS database <url>http://cg1.iis.sinica.edu.tw/~mybs/</url>, the ratios of TF-sharing pairs among all the adjacent pairs in yeast genomes were analyzed. The levels of co-expression in different adjacent patterns were also compared.</p> <p>Results</p> <p>Our analyses showed that the proportion of adjacent pairs conserved in five yeast species is relatively low compared to that in the mammalian lineage. The proportion was also low for adjacent gene pairs with shared TFs. Particularly, the statistical analysis suggested that co-expression of adjacent gene pairs was not noticeably associated with the sharing of TFs in these pairs. We further proposed a case of the PAC (polymerase A and C) and RRPE (rRNA processing element) motifs which co-regulate divergent/bidirectional pairs, and found that the shared TFs were not significantly relevant to co-expression of divergent promoters among adjacent genes.</p> <p>Conclusion</p> <p>Our findings suggested that the commonly shared <it>cis</it>-regulatory system does not solely contribute to the co-expression of adjacent gene pairs in yeast genome. Therefore we believe that during evolution yeasts have developed a sophisticated regulatory system that integrates both TF-based and non-TF based mechanisms(s) for concurrent regulation of neighboring genes in response to various environmental changes.</p

Doped graphene nanohole arrays for flexible transparent conductors

Graphene nanohole arrays (GNAs) were fabricated using nanoimprint lithography. The improved optical transmittance of GNAs is primarily due to the reduced surface coverage of graphene from the nanohole fabrication. Importantly, the exposed edges of the nanoholes provided effective sites for chemical doping using thionyl chloride was shown to enhance the conductance by a factor of 15–18 in contrast to only 2-4 for unpatterned graphene. GNAs can provide a unique scheme for improving both optical transmittance and electrical conductivity of graphene-based transparent conductors

Using Online Digital Tools and Video to Support International Problem-Based Learning

The goal of this study is to examine how to facilitate cross-cultural groups in problem-based learning (PBL) using online digital tools and videos. The PBL consisted of two video-based cases used to trigger student-learning issues about giving bad news to HIV-positive patients. Mixed groups of medical students from Canada and Hong Kong worked with facilitators from each country along with an expert facilitator. The study used AdobeConnect to support the international model through synchronous video interaction and shared applications. This study examines strategies and challenges in facilitating PBL across distance and cultures. Discourse was analyzed using both an inductive and deductive approach where the later used the Community of Inquiry coding scheme. The international context provides a way to facilitate multiple perspectives about how to communicate bad news to patients from different cultural backgrounds. In addition, we present the results of an exploratory analysis of pre and post tests using a standardized patient that demonstrate that the students’ pattern of communication showed qualitative change. Several conjectures were developed for future research

Dietary Fat Content and Fiber Type Modulate Hind Gut Microbial Community and Metabolic Markers in the Pig

Obesity leads to changes in the gut microbial community which contribute to the metabolic dysregulation in obesity. Dietary fat and fiber affect the caloric density of foods. The impact of dietary fat content and fiber type on the microbial community in the hind gut is unknown. Effect of dietary fat level and fiber type on hindgut microbiota and volatile fatty acid (VFA) profiles was investigated. Expression of metabolic marker genes in the gut, adipose tissue and liver was determined. A 2×2 experiment was conducted in pigs fed at two dietary fat levels (5% or 17.5% swine grease) and two fiber types (4% inulin, fermentable fructo-oligosaccharide or 4% solka floc, non-fermentable cellulose). High fat diets (HFD) resulted in a higher (