Publications by authors named "Ryota Koga"

In many bacteria, cyclic diguanosine monophosphate (c-di-GMP), synthesized by diguanylate cyclase (DGC), serves as a second messenger involved in the regulation of biofilm formation. Although studies have suggested that c-di-GMP also regulates the formation of electrochemically active biofilms (EABFs) by MR-1, DGCs involved in this process remained to be identified. Here, we report that the SO_1646 gene, hereafter named , is upregulated under medium flow conditions in electrochemical flow cells (EFCs), and its product (DgcS) functions as a major DGC in MR-1.

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Article Synopsis
  • Shewanella oneidensis MR-1 was studied in electrochemical flow cells, and it was found that the SO_3096 gene, which encodes a specific sigma factor, is crucial for the bacteria's interaction with electrodes, especially under flowing electrolyte conditions.
  • The deletion of the SO_3096 gene led to reduced biofilm formation and lower current generation, demonstrating its significance in bioelectrical processes.
  • Additionally, SO_3096 regulates other important genes, like dsbD, which is essential for proper electron transfer to electrodes, highlighting the gene's role in c-type cytochrome maturation and overall extracellular electron transfer.
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To identify exoelectrogens involved in the generation of electricity from complex organic matter in coastal sediment (CS) microbial fuel cells (MFCs), MFCs were inoculated with CS obtained from tidal flats and estuaries in the Tokyo bay and supplemented with starch, peptone, and fish extract as substrates. Power output was dependent on the CS used as inocula and ranged between 100 and 600 mW m (based on the projected area of the anode). Analyses of anode microbiomes using 16S rRNA gene amplicons revealed that the read abundance of some bacteria, including those related to Shewanella algae, positively correlated with power outputs from MFCs.

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A woman in her seventies who was started on warfarin after heart valve replacement began outpatient adjuvant chemotherapy with tegafur-uracil/leucovorin for rectal cancer. The patient performed weekly INR self-measurements at a health insurance pharmacy between outpatient visits. Results recorded in her personal medicine notebook were shared between her physician, a hospital pharmacist, and a pharmacy pharmacist.

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An electrochemical flow cell equipped with a graphite working electrode (WE) at the bottom was inoculated with MR-1 expressing an anaerobic fluorescent protein, and biofilm formation on the WE was observed over time during current generation at WE potentials of +0.4 and 0 V (versus standard hydrogen electrodes), under electrolyte-flow conditions. Electrochemical analyses suggested the presence of unique electron-transfer mechanisms in the +0.

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The growing power of central processing units (CPU) has made it possible to use quantum mechanical (QM) calculations for in silico drug discovery. However, limited CPU power makes large-scale in silico screening such as virtual screening with QM calculations a challenge. Recently, general-purpose computing on graphics processing units (GPGPU) has offered an alternative, because of its significantly accelerated computational time over CPU.

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We investigated the mechanical nature of multiply hydrogen-bonded systems by means of ab initio quantum chemical calculations, and we derived a set of force constants to reproduce the anisotropic vibration modes of such systems. Twenty multiply hydrogen-bonded molecular dimers were selected for evaluation of the stiffness of their hydrogen bonds. By means of a multivariate analysis, the principal values of the stiffness tensor were divided into the contributions from each hydrogen bond.

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