5 research outputs found
Disposable Strip Biosensor for Visual Detection of Hg<sup>2+</sup> Based on Hg<sup>2+</sup>-Triggered Toehold Binding and Exonuclease III-Assisted Signal Amplification
A disposable
strip biosensor for the visual detection of Hg<sup>2+</sup> in aqueous
solution has been constructed on the basis of
Hg<sup>2+</sup>-triggered toehold binding and exonuclease III (Exo
III)-assisted signal amplification. Thymine-thymine (T-T) mismatches
in the toehold domains can serve as specific recognition elements
for Hg<sup>2+</sup> binding with the help of T-Hg<sup>2+</sup>-T base
pairs to initiate toehold-mediated strand displacement reaction. Exo
III-catalyzed target recycling strategy is introduced to improve the
sensitivity. Using gold nanoparticles as a tracer, the output signals
can be directly observed by the naked eye. The assay is ultrasensitive,
enabling the visual detection of trace amounts of Hg<sup>2+</sup> as
low as 1 pM without instrumentation. This sensing system also displays
remarkable specificity to Hg<sup>2+</sup> against other possible competing
ions. This sensor is robust and can be applied to the reliable monitoring
of spiked Hg<sup>2+</sup> in environmental water samples with good
recovery and accuracy. With the advantages of cost-effectiveness,
simplicity, portability, and convenience, the disposable strip biosensor
will be a promising candidate for point-of-use monitoring of Hg<sup>2+</sup> in environmental and biological samples
Rapid Measurement of Microbial Extracellular Respiration Ability Using a High-Throughput Colorimetric Assay
Microbial extracellular respiration
(MER) involves the transfer
of electrons to extracellular substrates and has significant environmental
implications. Conventional methods for MER ability determination are
reagent- and time-consuming, have a low throughput, or require noncommercial
instruments. In this study, a plate-based colorimetric assay is proposed
to measure MER ability. This method utilizes the peroxidase activity
of the key components (multi-heme <i>c</i>-type cytochromes)
of the extracellular electron-transfer network. The bacterial intrinsic
peroxidase-catalyzed oxidation of chromogen (e.g., tetramethylbenzidine)
resulted in a measurable color change correlated with the MER ability
of the tested microorganisms. The results of the proposed colorimetric
assay correspond well with those of traditional methods, such as the
dissimilatory FeĀ(III) reduction method (Spearmanās Ļ
of 0.946; <i>P</i> < 0.01) and the electricity generation
method (Spearmanās Ļ of 0.893; <i>P</i> <
0.01). The proposed method allows researchers to identify extracellular
respiring bacteria within several minutes and to measure their MER
ability quantitatively by a plate-based assay
Table_1_Transcriptomic, Proteomic, and Bioelectrochemical Characterization of an Exoelectrogen Geobacter soli Grown With Different Electron Acceptors.xlsx
<p>The ability of Geobacter species to transfer electrons outside cells enables them to play an important role in biogeochemical and bioenergy processes. Our knowledge of the extracellular electron transfer (EET) process in the genus Geobacter is mainly from the study of G. sulfurreducens, and in order to fully investigate the EET mechanisms in the genus Geobacter, other Geobacter species should also be considered. This study focused on the EET of Geobacter soli GSS01, which exhibited a capability of reducing insoluble Fe(III) oxides and generating electrical current comparable with G. sulfurreducens PCA. Electrochemical characterization, including cyclic voltammetry, differential pulse voltammetry, and electrochemical in situ FTIR spectra, revealed that different redox proteins contributed to the electrochemical behaviors of G. soli and G. sulfurreducens. Based on comparative transcriptomic and proteomic analyses, OmcS was the most upregulated protein in both G. soli and G. sulfurreducens cells grown with insoluble Fe(III) oxides vs. soluble electron acceptor. However, the proteins including OmcE and PilA that were previously reported as being important for EET in G. sulfurreducens were downregulated or unchanged in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, and many proteins that were upregulated in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, such as OmcN, are not important for EET in G. sulfurreducens. We also identified 30 differentially expressed small RNAs (sRNAs) in G. soli cells grown with different acceptors. Taken together, these findings help to understand the versatile EET mechanisms that exist in the genus Geobacter and point to the possibility of sRNA in modulating EET gene expression.</p
Table_3_Transcriptomic, Proteomic, and Bioelectrochemical Characterization of an Exoelectrogen Geobacter soli Grown With Different Electron Acceptors.pdf
<p>The ability of Geobacter species to transfer electrons outside cells enables them to play an important role in biogeochemical and bioenergy processes. Our knowledge of the extracellular electron transfer (EET) process in the genus Geobacter is mainly from the study of G. sulfurreducens, and in order to fully investigate the EET mechanisms in the genus Geobacter, other Geobacter species should also be considered. This study focused on the EET of Geobacter soli GSS01, which exhibited a capability of reducing insoluble Fe(III) oxides and generating electrical current comparable with G. sulfurreducens PCA. Electrochemical characterization, including cyclic voltammetry, differential pulse voltammetry, and electrochemical in situ FTIR spectra, revealed that different redox proteins contributed to the electrochemical behaviors of G. soli and G. sulfurreducens. Based on comparative transcriptomic and proteomic analyses, OmcS was the most upregulated protein in both G. soli and G. sulfurreducens cells grown with insoluble Fe(III) oxides vs. soluble electron acceptor. However, the proteins including OmcE and PilA that were previously reported as being important for EET in G. sulfurreducens were downregulated or unchanged in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, and many proteins that were upregulated in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, such as OmcN, are not important for EET in G. sulfurreducens. We also identified 30 differentially expressed small RNAs (sRNAs) in G. soli cells grown with different acceptors. Taken together, these findings help to understand the versatile EET mechanisms that exist in the genus Geobacter and point to the possibility of sRNA in modulating EET gene expression.</p
Table_4_Transcriptomic, Proteomic, and Bioelectrochemical Characterization of an Exoelectrogen Geobacter soli Grown With Different Electron Acceptors.xlsx
<p>The ability of Geobacter species to transfer electrons outside cells enables them to play an important role in biogeochemical and bioenergy processes. Our knowledge of the extracellular electron transfer (EET) process in the genus Geobacter is mainly from the study of G. sulfurreducens, and in order to fully investigate the EET mechanisms in the genus Geobacter, other Geobacter species should also be considered. This study focused on the EET of Geobacter soli GSS01, which exhibited a capability of reducing insoluble Fe(III) oxides and generating electrical current comparable with G. sulfurreducens PCA. Electrochemical characterization, including cyclic voltammetry, differential pulse voltammetry, and electrochemical in situ FTIR spectra, revealed that different redox proteins contributed to the electrochemical behaviors of G. soli and G. sulfurreducens. Based on comparative transcriptomic and proteomic analyses, OmcS was the most upregulated protein in both G. soli and G. sulfurreducens cells grown with insoluble Fe(III) oxides vs. soluble electron acceptor. However, the proteins including OmcE and PilA that were previously reported as being important for EET in G. sulfurreducens were downregulated or unchanged in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, and many proteins that were upregulated in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, such as OmcN, are not important for EET in G. sulfurreducens. We also identified 30 differentially expressed small RNAs (sRNAs) in G. soli cells grown with different acceptors. Taken together, these findings help to understand the versatile EET mechanisms that exist in the genus Geobacter and point to the possibility of sRNA in modulating EET gene expression.</p