A simple biofuel cell cathode with human red blood cells as electrocatalysts for oxygen reduction reaction

A red blood cell (RBC) from human exhibited direct electron transfer (DET) activity on a bare indium tin oxide (ITO) electrode. A formal potential of 0.152 V vs. a silver-silver chloride saturated potassium chloride (AglAgClIKCI(satd.)) was estimated for the human RBC (type AB) from a pair of redox peaks at around 0.089 and 0.215 V (vs. AglAgClIKC1(satd.)) on cyclic voltammetric (CV) measurements in a phosphate buffered saline (PBS; 39 mM; pH 7.4) solution. The results agreed well with those of a redox couple for iron-bearing heme groups in hemoglobin molecules (HbFe(1I)/HbFe(III)) on the bare ITO electrodes, indicated that DET active species were hemoglobin (Hb) molecules encapsulated by a phospholipid bilayer membrane of the human BBC. The quantity of electrochemically active Hb in the human RBC was estimated to be 30 pmol cm(-2). In addition, the human RBC exhibited oxygen reduction reaction (ORR) activity in the dioxygen (O2) saturated PBS solution at the negative potential from ca. 0.15 V (vs. AglAgClIKC1(satd.)). A single cell test proved that a biofuel cell (BFC) with an O2IRBCIITO cathode showed the open-circuit voltage (OCV) of ca. 0.43 V and the maximum power density of ca. 0.6811W cm(-2).ArticleBIOSENSORS & BIOELECTRONICS. 55:14-18 (2014)journal articl

Annual (2023) taxonomic update of RNA-directed RNA polymerase-encoding negative-sense RNA viruses (realm Riboviria: kingdom Orthornavirae: phylum Negarnaviricota)

55 Pág.In April 2023, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by one new family, 14 new genera, and 140 new species. Two genera and 538 species were renamed. One species was moved, and four were abolished. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.This work was supported in part through the Laulima Government Solutions, LLC, prime contract with the U.S. National Institute of Allergy and Infec tious Diseases (NIAID) under Contract No. HHSN272201800013C. J.H.K. performed this work as an employee of Tunnell Government Services (TGS), a subcontractor of Laulima Government Solutions, LLC, under Contract No. HHSN272201800013C. U.J.B. was supported by the Division of Intramural Resarch, NIAID. This work was also funded in part by Contract No. HSHQDC15-C-00064 awarded by DHS S and T for the management and operation of The National Biodefense Analysis and Countermeasures Centre, a federally funded research and development centre operated by the Battelle National Biodefense Institute (V.W.); and NIH contract HHSN272201000040I/HHSN27200004/D04 and grant R24AI120942 (N.V., R.B.T.). S.S. acknowl edges support from the Mississippi Agricultural and Forestry Experiment Station (MAFES), USDA-ARS project 58-6066-9-033 and the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch Project, under Accession Number 1021494. The funders had no role in the design of the study; in the collection, analysis, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of the Army, the U.S. Department of Defence, the U.S. Department of Health and Human Services, including the Centres for Disease Control and Prevention, the U.S. Department of Homeland Security (DHS) Science and Technology Directorate (S and T), or of the institutions and companies affiliated with the authors. In no event shall any of these entities have any responsibility or liability for any use, misuse, inability to use, or reliance upon the information contained herein. The U.S. departments do not endorse any products or commercial services mentioned in this publication. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S.Government retains a non-exclusive, paid up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. Government purposes.Peer reviewe

Modeling the efficiency of filovirus entry into cells in vitro: Effects of SNP mutations in the receptor molecule.

Interaction between filovirus glycoprotein (GP) and the Niemann-Pick C1 (NPC1) protein is essential for membrane fusion during virus entry. Some single-nucleotide polymorphism (SNPs) in two surface-exposed loops of NPC1 are known to reduce viral infectivity. However, the dependence of differences in entry efficiency on SNPs remains unclear. Using vesicular stomatitis virus pseudotyped with Ebola and Marburg virus GPs, we investigated the cell-to-cell spread of viruses in cultured cells expressing NPC1 or SNP derivatives. Eclipse and virus-producing phases were assessed by in vitro infection experiments, and we developed a mathematical model describing spatial-temporal virus spread. This mathematical model fit the plaque radius data well from day 2 to day 6. Based on the estimated parameters, we found that SNPs causing the P424A and D508N substitutions in NPC1 most effectively reduced the entry efficiency of Ebola and Marburg viruses, respectively. Our novel approach could be broadly applied to other virus plaque assays

Evaluation of Biofuel Cells with Hemoglobin as Cathodic Electrocatalysts for Hydrogen Peroxide Reduction on Bare Indium-Tin-Oxide Electrodes

A biofuel cell (BFC) cathode has been developed based on direct electron transfer (DET) of hemoglobin (Hb) molecules with an indium-tin-oxide (ITO) electrode and their electrocatalysis for reduction of hydrogen peroxide (H2O2). In this study, the ITO-coated glass plates or porous glasses were prepared by using a chemical vapor deposition (CVD) method and examined the electrochemical characteristics of the formed ITO in pH 7.4 of phosphate buffered saline (PBS) solutions containing and not containing Hb. In half-cell measurements, the reduction current of H2O2 due to the electrocatalytic activity of Hb increased with decreasing electrode potential from around 0.1 V versus Ag|AgCl|KCl(satd.) in the PBS solution. The practical open-circuit voltage (OCV) on BFCs utilizing H2O2 reduction at the Hb-ITO cathode with a hydrogen (H2) oxidation anode at a platinum (Pt) electrode was expected to be at least 0.74 V from the theoretical H2 oxidation potential of −0.64 V versus Ag|AgCl|KCl(satd.) in pH 7.4. The assembled single cell using the ITO-coated glass plate showed the OCV of 0.72 V and the maximum power density of 3.1 µW cm−2. The maximum power per single cell was recorded at 21.5 µW by using the ITO-coated porous glass

Microdiversity and phylogeographic diversification of bacterioplankton in pelagic freshwater systems revealed through long-read amplicon sequencing

[Background] Freshwater ecosystems are inhabited by members of cosmopolitan bacterioplankton lineages despite the disconnected nature of these habitats. The lineages are delineated based on > 97% 16S rRNA gene sequence similarity, but their intra-lineage microdiversity and phylogeography, which are key to understanding the eco-evolutional processes behind their ubiquity, remain unresolved. Here, we applied long-read amplicon sequencing targeting nearly full-length 16S rRNA genes and the adjacent ribosomal internal transcribed spacer sequences to reveal the intra-lineage diversities of pelagic bacterioplankton assemblages in 11 deep freshwater lakes in Japan and Europe. [Results] Our single nucleotide-resolved analysis, which was validated using shotgun metagenomic sequencing, uncovered 7–101 amplicon sequence variants for each of the 11 predominant bacterial lineages and demonstrated sympatric, allopatric, and temporal microdiversities that could not be resolved through conventional approaches. Clusters of samples with similar intra-lineage population compositions were identified, which consistently supported genetic isolation between Japan and Europe. At a regional scale (up to hundreds of kilometers), dispersal between lakes was unlikely to be a limiting factor, and environmental factors or genetic drift were potential determinants of population composition. The extent of microdiversification varied among lineages, suggesting that highly diversified lineages (e.g., Iluma-A2 and acI-A1) achieve their ubiquity by containing a consortium of genotypes specific to each habitat, while less diversified lineages (e.g., CL500-11) may be ubiquitous due to a small number of widespread genotypes. The lowest extent of intra-lineage diversification was observed among the dominant hypolimnion-specific lineage (CL500-11), suggesting that their dispersal among lakes is not limited despite the hypolimnion being a more isolated habitat than the epilimnion. [Conclusions] Our novel approach complemented the limited resolution of short-read amplicon sequencing and limited sensitivity of the metagenome assembly-based approach, and highlighted the complex ecological processes underlying the ubiquity of freshwater bacterioplankton lineages. To fully exploit the performance of the method, its relatively low read throughput is the major bottleneck to be overcome in the future