Roles of RpoN in the resistance of Campylobacter jejuni under various stress conditions

<p>Abstract</p> <p>Background</p> <p><it>Campylobacter jejuni </it>is a leading foodborne pathogen worldwide. Despite the fastidious nature of <it>C. jejuni </it>growth, increasing numbers of human campylobacteriosis suggest that <it>C. jejuni </it>may possess unique mechanisms to survive under various stress conditions. <it>C. jejuni </it>possesses only three sigma factors (FliA, RpoD, and RpoN) and lacks stress-defense sigma factors. Since FliA and RpoD are dedicated to flagella synthesis and housekeeping, respectively, in this study, we investigated the role of RpoN in <it>C. jejuni</it>'s defense against various stresses.</p> <p>Results</p> <p>Survivability of an <it>rpoN </it>mutant was compared with the wild-type <it>C. jejuni </it>under various stress conditions. While the growth of the <it>rpoN </it>mutant was as comparably as that of the wild type in shaking cultures, the <it>rpoN </it>mutant exhibited significant survival defects when cultured statically. The <it>rpoN </it>mutant was more sensitive to osmotic stress (0.8% NaCl) with abnormally-elongated cell morphology. Compared to the wile type, the <it>rpoN </it>mutant was more susceptible to acid stress (pH 5) and more resistant to hydrogen peroxide. However, the <it>rpoN </it>mutation had little effect on the resistance of <it>C. jejuni </it>to alkaline pH, heat, cold and antimicrobials.</p> <p>Conclusions</p> <p>The results demonstrate that RpoN plays an important role in <it>C. jejuni</it>'s defense against various stresses which this bacterial pathogen may encounter during transmission to and infection of humans.</p

A Preliminary Study for Structural Curriculum Development for Teaching Korean Culture Abroad - An Analysis of Current Korean Program Management in Europe -

This paper aims to provide preliminary research to show the need for and to build a structural curriculum model for teaching Korean culture in Korean Studies abroad. It analyses the current management of Korean cultural programs in European universities. Despite the recent increased number of higher education institutions offering Korean Studies programs abroad, studies on the specific curricular framework of how Korean culture is taught has been insufficient. Thus, this paper investigates the current management of Korean cultural education in 159 European universities across 36 countries using the Korea Foundation database. The findings show a large majority of universities offer modules on Korean culture, even at those institutions that do not offer Korean studies at the degree level. This indicates that Korean culture education form a significant role in Korean studies programs at European universities

Comparative genome analysis of rice-pathogenic Burkholderia provides insight into capacity to adapt to different environments and hosts

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Background In addition to human and animal diseases, bacteria of the genus Burkholderia can cause plant diseases. The representative species of rice-pathogenic Burkholderia are Burkholderia glumae, B. gladioli, and B. plantarii, which primarily cause grain rot, sheath rot, and seedling blight, respectively, resulting in severe reductions in rice production. Though Burkholderia rice pathogens cause problems in rice-growing countries, comprehensive studies of these rice-pathogenic species aiming to control Burkholderia-mediated diseases are only in the early stages. Results We first sequenced the complete genome of B. plantarii ATCC 43733T. Second, we conducted comparative analysis of the newly sequenced B. plantarii ATCC 43733T genome with eleven complete or draft genomes of B. glumae and B. gladioli strains. Furthermore, we compared the genome of three rice Burkholderia pathogens with those of other Burkholderia species such as those found in environmental habitats and those known as animal/human pathogens. These B. glumae, B. gladioli, and B. plantarii strains have unique genes involved in toxoflavin or tropolone toxin production and the clustered regularly interspaced short palindromic repeats (CRISPR)-mediated bacterial immune system. Although the genome of B. plantarii ATCC 43733T has many common features with those of B. glumae and B. gladioli, this B. plantarii strain has several unique features, including quorum sensing and CRISPR/CRISPR-associated protein (Cas) systems. Conclusions The complete genome sequence of B. plantarii ATCC 43733T and publicly available genomes of B. glumae BGR1 and B. gladioli BSR3 enabled comprehensive comparative genome analyses among three rice-pathogenic Burkholderia species responsible for tissue rotting and seedling blight. Our results suggest that B. glumae has evolved rapidly, or has undergone rapid genome rearrangements or deletions, in response to the hosts. It also, clarifies the unique features of rice pathogenic Burkholderia species relative to other animal and human Burkholderia species

Nogo-A regulates myogenesis via interacting with Filamin-C

Among the three isoforms encoded by Rtn4, Nogo-A has been intensely investigated as a central nervous system inhibitor. Although Nogo-A expression is increased in muscles of patients with amyotrophic lateral sclerosis, its role in muscle homeostasis and regeneration is not well elucidated. In this study, we discovered a significant increase in Nogo-A expression in various muscle-related pathological conditions. Nogo−/− mice displayed dystrophic muscle structure, dysregulated muscle regeneration following injury, and altered gene expression involving lipid storage and muscle cell differentiation. We hypothesized that increased Nogo-A levels might regulate muscle regeneration. Differentiating myoblasts exhibited Nogo-A upregulation and silencing Nogo-A abrogated myoblast differentiation. Nogo-A interacted with filamin-C, suggesting a role for Nogo-A in cytoskeletal arrangement during myogenesis. In conclusion, Nogo-A maintains muscle homeostasis and integrity, and pathologically altered Nogo-A expression mediates muscle regeneration, suggesting Nogo-A as a novel target for the treatment of myopathies in clinical settings. © 2021, The Author(s).1

Regulation of Oxidative Stress Response by CosR, an Essential Response Regulator in Campylobacter jejuni

CosR (Campylobacter oxidative stress regulator; Cj0355c) is an OmpR-type response regulator essential for the viability of Campylobacter jejuni, a leading foodborne pathogen causing human gastroenteritis worldwide. Despite importance, the function of CosR remains completely unknown mainly because of cell death caused by its knockout mutation. To overcome this technical limitation, in this study, antisense technology was used to investigate the regulatory function of CosR by modulating the level of CosR expression. Two-dimensional gel electrophoresis (2DGE) was performed to identify the CosR regulon either by suppressing CosR expression with antisense peptide nucleic acid (PNA) or by overexpressing CosR in C. jejuni. According to the results of 2DGE, CosR regulated 32 proteins involved in various cellular processes. Notably, CosR negatively regulated a few key proteins of the oxidative stress response of C. jejuni, such as SodB, Dps, Rrc and LuxS, whereas CosR positively controlled AhpC. Electrophoretic mobility shift assay showed that CosR directly bound to the promoter region of the oxidative stress genes. DNase I footprinting assays identified 21-bp CosR binding sequences in the sodB and ahpC promoters, suggesting CosR specifically recognizes and binds to the regulated genes. Interestingly, the level of CosR protein was significantly reduced by paraquat (a superoxide generator) but not by hydrogen peroxide. Consistent with the overall negative regulation of oxidative stress defense proteins by CosR, the CosR knockdown by antisense rendered C. jejuni more resistant to oxidative stress compared to the wild type. Overall, this study reveals the important role played by the essential response regulator CosR in the oxidative stress defense of C. jejuni

Semantic Network Analysis Using Construction Accident Cases to Understand Workers&rsquo; Unsafe Acts

Unsafe acts by workers are a direct cause of accidents in the labor-intensive construction industry. Previous studies have reviewed past accidents and analyzed their causes to understand the nature of the human error involved. However, these studies focused their investigations on only a small number of construction accidents, even though a large number of them have been collected from various countries. Consequently, this study developed a semantic network analysis (SNA) model that uses approximately 60,000 construction accident cases to understand the nature of the human error that affects safety in the construction industry. A modified human factor analysis and classification system (HFACS) framework was used to classify major human error factors&mdash;that is, the causes of the accidents in each of the accident summaries in the accident case data&mdash;and an SNA analysis was conducted on all of the classified data to analyze correlations between the major factors that lead to unsafe acts. The results show that an overwhelming number of accidents occurred due to unintended acts such as perceptual errors (PERs) and skill-based errors (SBEs). Moreover, this study visualized the relationships between factors that affected unsafe acts based on actual construction accident case data, allowing for an intuitive understanding of the major keywords for each of the factors that lead to accidents