1,720,971 research outputs found
Genome-scale analysis of Acetobacterium bakii reveals the cold adaptation of psychrotolerant acetogens by post-transcriptional regulation
No full textAcetogens synthesize acetyl-CoA via CO2 or CO fixation, producing organic compounds. Despite their ecological and industrial importance, their transcriptional and post-transcriptional regulation has not been systematically studied. With completion of the genome sequence of Acetobacterium bakii (4.28-Mb), we measured changes in the transcriptome of this psychrotolerant acetogen in response to temperature variations under autotrophic and heterotrophic growth conditions. Unexpectedly, acetogenesis genes were highly up-regulated at low temperatures under heterotrophic, as well as autotrophic, growth conditions. To mechanistically understand the transcriptional regulation of acetogenesis genes via changes in RNA secondary structures of 5'-untranslated regions (5'-UTR), the primary transcriptome was experimentally determined, and 1379 transcription start sites (TSS) and 1100 5'-UTR were found. Interestingly, acetogenesis genes contained longer 5'-UTR with lower RNA-folding free energy than other genes, revealing that the 5'-UTRs control the RNA abundance of the acetogenesis genes under low temperature conditions. Our findings suggest that post-transcriptional regulation via RNA conformational changes of 5'-UTRs is necessary for cold-adaptive acetogenesis.
Genome Engineering of Eubacterium limosum Using Expanded Genetic Tools and the CRISPR-Cas9 System
No full textEubacterium limosum is one of the important bacteria in C-1 feedstock utilization as well as in human gut microbiota. Although E. limosum has recently garnered much attention and investigation on a genome-wide scale, a bottleneck for systematic engineering in E. limosum is the lack of available genetic tools and an efficient genome editing platform. To overcome this limitation, we here report expanded genetic tools and the CRISPR-Cas9 system. We have developed an inducible promoter system that enables implementation of the CRISPR-Cas9 system to precisely manipulate target genes of the Wood-Ljungdahl pathway with 100% efficiency. Furthermore, we exploited the effectiveness of CRISPR interference to reduce the expression of target genes, exhibiting substantial repression of several genes in the Wood-Ljungdahl pathway and fructose-PTS system. These expanded genetic tools and CRISPR-Cas9 system comprise powerful and widely applicable genetic tools to accelerate functional genomic study and genome engineering in E. limosum.
Additional file 9: of Genome-scale analysis of syngas fermenting acetogenic bacteria reveals the translational regulation for its autotrophic growth
No full textFigure S1. Translatome analysis of E. limosum ATCC 8486. (a) Comparison between RNA-Seq and Ribo-Seq under heterotrophic condition. Scatter plot between ribosome-protected fragment profile (RPF) as the y-axis and mRNA expression (mRNA) as the x-axis. (b) Comparison between RNA-Seq and Ribo-Seq under autotrophic conditions. The results show positive correlation with R2 of 0.55 and 0.67, respectively. (TIF 1104 kb
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Fabricating nanowire devices on diverse substrates by simple transfer-printing methods
No full textThe fabrication of nanowire (NW) devices on diverse substrates is necessary for applications such as flexible electronics, conformable sensors, and transparent solar cells. Although NWs have been fabricated on plastic and glass by lithographic methods, the choice of device substrates is severely limited by the lithographic process temperature and substrate properties. Here we report three new transfer-printing methods for fabricating NW devices on diverse substrates including polydimethylsiloxane, Petri dishes, Kapton tapes, thermal release tapes, and many types of adhesive tapes. These transfer-printing methods rely on the differences in adhesion to transfer NWs, metal films, and devices from weakly adhesive donor substrates to more strongly adhesive receiver substrates. Electrical characterization of fabricated NW devices shows that reliable ohmic contacts are formed between NWs and electrodes. Moreover, we demonstrated that Si NW devices fabricated by the transfer-printing methods are robust piezoresistive stress sensors and temperature sensors with reliable performance
Quantitative analysis of anti-freezing characteristics of superhydrophobic surfaces according to initial ice nuclei formation time and freezing propagation velocity
No full textIn order to quantitatively analyze the anti-freezing characteristics of superhydrophobic and bare surfaces, the freezing delay properties of the surfaces were experimentally investigated under various operating conditions by placing sessile droplets on their surface. The freezing delay time was calculated using the experimental results and analyzed by employing a stochastic method. The formation time of initial ice nuclei and freezing propagation velocity at a macroscopic level were proposed as measures of surface anti-freezing characteristics. The anti-freezing properties of the bare and superhydrophobic surfaces were analyzed using the proposed quantitative measures. Consequently, the tendency of quantitative results was consistent with that of the qualitative ones according to the changes of the operating conditions (air inlet velocity, relative humidity, and surface temperature). Moreover, the superior anti-freezing performance of the superhydrophobic surface was quantitatively confirmed by the initial ice nuclei formation time, which was delayed by 22-92%, and the freezing propagation velocity, which decreased by 17-30%.This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2016R1A2B4012954).This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20164010200860)
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Quantitative analysis of anti-freezing characteristics of superhydrophobic surfaces according to initial ice nuclei formation time and freezing propagation velocity
No full textIn order to quantitatively analyze the anti-freezing characteristics of superhydrophobic and bare surfaces, the freezing delay properties of the surfaces were experimentally investigated under various operating conditions by placing sessile droplets on their surface. The freezing delay time was calculated using the experimental results and analyzed by employing a stochastic method. The formation time of initial ice nuclei and freezing propagation velocity at a macroscopic level were proposed as measures of surface anti-freezing characteristics. The anti-freezing properties of the bare and superhydrophobic surfaces were analyzed using the proposed quantitative measures. Consequently, the tendency of quantitative results was consistent with that of the qualitative ones according to the changes of the operating conditions (air inlet velocity, relative humidity, and surface temperature). Moreover, the superior anti-freezing performance of the superhydrophobic surface was quantitatively confirmed by the initial ice nuclei formation time, which was delayed by 22-92%, and the freezing propagation velocity, which decreased by 17-30%. (C) 2018 Elsevier Ltd. All rights reserved.This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2016R1A2B4012954).This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20164010200860)
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