Department of Biochemistry, Microbiology and Biotechnology, Faculty of Biology, Yerevan State University, 1 Alex Manoogian, 0025, Yerevan, Armenia; Scientific-Research Institute of Biology Faculty of Biology, Yerevan State University, 0025, Yerevan, Armenia; Microbial Biotechnologies and Biofuel Innovation Center, Yerevan State University, 0025, Yerevan, Armenia. Electronic address:
Published: February 2024
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Article Abstract
Pentameric FocA permeates either formate or formic acid bidirectionally across the cytoplasmic membrane of anaerobically growing Escherichia coli. Each protomer of FocA has its own hydrophobic pore, but it is unclear whether formate or neutral formic acid is translocated in vivo. Here, we measured total and dicyclohexylcarbodiimide (DCCD)-inhibited proton flux out of resting, fermentatively grown, stationary-phase E. coli cells in dependence on FocA. Using a wild-type strain synthesizing native FocA, it was shown that using glucose as a source of formate, DCCD-independent proton efflux was ∼2.5 mmol min, while a mutant lacking FocA showed only DCCD-inhibited, FF-ATPase-dependent proton-efflux. A strain synthesizing a chromosomally-encoded FocA variant that functions exclusively to translocate formic acid out of the cell, showed a further 20 % increase in FocA-dependent proton efflux relative to the parental strain. Cells synthesizing a FocA variant, which is unable to translocate formic acid out of the cell, showed only DCCD-inhibited proton efflux. When exogenous formate was added, formic acid uptake was shown to be both FocA- and proton motive force-dependent. By measuring rates of H production, potassium ion flux and ATPase activity, these data support a role for coupling between formate, proton and K ion translocation in maintaining pH and ion gradient homeostasis during fermentation. FocA thus plays a key role in maintaining this homeostatic balance in fermenting cells by bidirectionally translocating formic acid.
Understanding the electrolyte factors governing the electrochemical CO reduction reaction (CORR) is fundamental for selecting the optimized electrolyte conditions for practical applications. While noble metals are frequently studied, the electrolyte effects on the CORR on Sn catalysts are not well explored. Here, we studied the electrolyte effect on Sn metallic electrodes, investigating the impact of electrolyte concentration, cation identity, and anion properties, and how it shapes the CORR activity and selectivity.
Tuning the selectivity and improving the activity of photocatalysts are among the main bottlenecks for the conversion of CO to value-added chemicals. Recently, lead-free halide perovskites have been extensively investigated as photocatalysts for the photoreduction of CO. Herein, we report a composite photocatalyst using CsBiCl and Ir/IrO for the photoreduction of CO.
An analytical method for identifying the chemical constituents in the Chinese herbal combination Jiuwei decoction was established using capillary electrophoresis coupled with quadrupole time-of-flight mass spectrometry. Nine herbs were extracted with a 60:40 (v/v) ethanol/water solution to prepare the Jiuwei decoction. Electrophoretic separation was carried out using a 50 µm i.
Introduction: The gut microbiome, allegedly involved in both healthy homeostasis and development of disease, is found to be associated with several types of cancer. Short chain fatty acids (SCFAs), important metabolites derived from the gut microbiota, are described to carry both protective and promoting features in cancer development. Limited research exists on neuroendocrine tumors (NET) and their association with microbiota derived SCFAs.
The catalytic efficiency of M-H2tpda pincer complexes (M = Mn(I), Fe(II), Co(III)) in CO2 hydrogenation, emphasizing the role of transition metal center variability have been discussed. The DFT analysis demonstrates that complexes with low αR values form weaker M-H bonds, enhancing catalyst reactivity with the elongation of M-H bond. The analysis further displays excellent catalytic performance for Mn-H2tpda (ΔE = 20.
