The antimicrobial effects of silver nanoparticles obtained through the royal jelly on the yeasts Candida guilliermondii NP-4.

The effect of silver nanoparticles (Ag NPs) obtained in the presence of royal jelly (RJ) on the growth of yeast Candida guilliermondii NP-4, on the total and H-ATPase activity, as well as lipid peroxidation process and antioxidant enzymes (superoxide dismutase (SOD), catalase) activity was studied. It has been shown that RJ-mediated Ag NPs have a fungicide and fungistatic effects at the concentrations of 5.4 µg mL and 27 µg mL, respectively.

Glucose concentration is determinant for the functioning of hydrogenase 1 and hydrogenase 2 in regulating the proton and potassium fluxes in Escherichia coli at pH 7.5.

This study examines how FF-ATPase, hydrogenases (Hyd-1 and Hyd-2), and potassium transport systems (TrkA) interact to maintain the proton motive force (pmf) in E. coli during fermentation of different glucose concentrations (2 g L and 8 g L). Our findings indicate that mutants lacking the hyaA-hyaC genes exhibited a 30 % increase in total proton flux compared to the wild type when grown with 2 g L glucose.

Proton conductance and regulation of proton/potassium fluxes in Escherichia coli FhlA-lacking cells during fermentation of mixed carbon sources.

Escherichia coli uptake potassium ions with the coupling of proton efflux and energy utilization via proton FF-ATPase. In this study contribution of formate hydrogen lyase (FHL) complexes in the proton/potassium fluxes and the formation of proton conductance (CH) were investigated using fhlA mutant strain. The proton flux rate (J) decreased in fhlA by ∼ 25 % and ∼70 % during the utilization of glucose and glycerol, respectively, at 20 h suggesting H transport via or through FHL complexes.

Regulation of metabolism and proton motive force generation during mixed carbon fermentation by an Escherichia coli strain lacking the FF-ATPase.

Proton FF-ATPase is the key enzyme in E. coli under fermentative conditions. In this study the role of E.

Changes in ATPase activity, antioxidant enzymes and proline biosynthesis in yeast Candida guilliermondii NP-4 under X-irradiation.

This study investigates the effects of X-radiation on ATPase activity and antioxidant enzyme activity, particularly enzymes involved in proline biosynthesis, in yeast C. guilliermondii NP-4. Moreover, the study examined the post-irradiation repair processes in these cells.

Osmotic stress as a factor for regulating hydrogenase activity and enhancing H production during mixed carbon sources fermentation.

performs mixed-acid fermentation and produces molecular hydrogen (H) via reversible hydrogenases (Hyd). H producing activity was investigated during hyper- and hypo-osmotic stress conditions when a mixture of carbon sources (glucose and glycerol) was fermented at different pHs. Hyper-osmotic stress decreased H production rate (V) ~30 % in wild type at pH 7.

Gold nanoparticles activate hydrogenase synthesis and improve heterotrophic growth of Ralstonia eutropha H16.

Ralstonia eutropha is a facultative chemolithoautotrophic aerobic bacterium that grows using organic substrates or H2 and CO2. Hydrogenases (Hyds) are synthesized under lithoautotrophic, or energy-limited heterotrophic conditions and are used in enzyme fuel cells (EFC) as anodic catalysts. The effects of chemically synthesized gold nanoparticles (Au-NPs) on R.

Evidence for bidirectional formic acid translocation in vivo via the Escherichia coli formate channel FocA.

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.

Propionic and valproic acids have an impact on bacteria viability, proton flux and ATPase activity.

Short-chain fatty acids like propionic (PPA) and valproic acids (VP) can alter gut microbiota, which is suggested to play a role in development of autism spectrum disorders (ASD). In this study we investigated the role of various concentrations of PPA and VP in gut enteric gram-negative Escherichia coli K12 and gram-positive Enterococcus hirae ATCC 9790 bacteria growth properties, ATPase activity and proton flux. The specific growth rate (µ) was 0.

Valorization of whey-based side streams for microbial biomass, molecular hydrogen, and hydrogenase production.

Side streams of the dairy industry are a suitable nutrient source for cultivating microorganisms, producing enzymes, and high-value chemical compounds. The heterotrophic Escherichia coli and chemolithoautotroph Ralstonia eutropha are of major biotechnological interest. R.

L-amino acids affect the hydrogenase activity and growth of Ralstonia eutropha H16.

Ralstonia eutropha H16 is a chemolithoautotrophic bacterium with O-tolerant hydrogenase (Hyds) enzymes. Hyds are expressed in the presence of gas mixtures (H, O, CO) or under energy limitation and stress conditions. O-tolerant Hyds are promising candidates as anode biocatalysts in enzymatic fuel cells (EFCs).

Metabolic pathways and ΔpH regulation in Escherichia coli during the fermentation of glucose and glycerol in the presence of formate at pH 6.5: the role of FhlA transcriptional activator.

Escherichia coli is able to ferment mixed carbon sources and produce various fermentation end-products. In this study, the function of FhlA protein in the specific growth rate (µ), metabolism, regulation of ΔpH and proton ATPase activity was investigated. Reduced µ in fhlA mutant of ∼25% was shown, suggesting the role of FhlA in the growth process.

L. Extract-Mediated Green Synthesis and Antibacterial Action Mechanisms of Silver Nanoparticles.

Silver nanoparticles (Ag NPs) represent one of the most widely employed metal-based engineered nanomaterials with a broad range of applications in different areas of science. Plant extracts (PEs) serve as green reducing and coating agents and can be exploited for the generation of Ag NPs. In this study, the phytochemical composition of ethanolic extract of black currant () leaves was determined.

Biosynthesis of silver nanoparticles using extracts of Stevia rebaudiana and evaluation of antibacterial activity.

The present study reveals a simple, non-toxic and eco-friendly method for the "green" synthesis of Ag-NPs using hydroponic and soil medicinal plant Stevia rebaudiana extracts, the characterization of biosynthesized nanoparticles, as well as the evaluation of their antibacterial activity. Transmission electronic microscopy (TEM) and Dynamic Light Scattering (DLS) analysis confirmed that biosynthesized Ag-NPs are in the nano-size range (50-100 nm) and have irregular morphology. Biogenic NPs demonstrate antibacterial activity against Escherichia coli BW 25,113, Enterococcus hirae ATCC 9790, and Staphylococcus aureus MDC 5233.

Structural characterization and antibacterial activity of silver nanoparticles synthesized using a low-molecular-weight Royal Jelly extract.

In recent years silver nanoparticles (Ag NPs) gained increased and widespread applications in various fields of industry, technology, and medicine. This study describes the green synthesis of silver nanoparticles (Ag NPs) applying a low-molecular-weight fraction (LMF) of Royal Jelly, the nanoparticle characterization, and particularly their antibacterial activity. The optical properties of NPs, characterized by UV-Vis absorption spectroscopy, showed a peak at ~ 430 nm.

HyfF subunit of hydrogenase 4 is crucial for regulating FF dependent proton/potassium fluxes during fermentation of various concentrations of glucose.

Escherichia coli anaerobically ferment glucose and perform proton/potassium exchange at pH 7.5. The role of hyf (hydrogenase 4) subunits (HyfBDF) in sensing different concentrations of glucose (2 g L or 8 g L) via regulating H/K exchange was studied.

Antibacterial activity of royal jelly-mediated green synthesized silver nanoparticles.

The application of green synthesis in nanotechnology is growing day by day. It's a safe and eco-friendly alternative to conventional methods. The current research aimed to study raw royal jelly's potential in the green synthesis of silver nanoparticles and their antibacterial activity.

The role of Escherichia coli FhlA transcriptional activator in generation of proton motive force and F F -ATPase activity at pH 7.5.

Escherichia coli is able to utilize the mixture of carbon sources and produce molecular hydrogen (H ) via formate hydrogen lyase (FHL) complexes. In current work role of transcriptional activator of formate regulon FhlA in generation of fermentation end products and proton motive force, N'N'-dicyclohexylcarbodiimide (DCCD)-sensitive ATPase activity at 20 and 72 hr growth during utilization of mixture of glucose, glycerol, and formate were investigated. It was shown that in fhlA mutant specific growth rate was ~1.

Roasted coffee wastes as a substrate for Escherichia coli to grow and produce hydrogen.

After brewing roasted coffee, spent coffee grounds (SCGs) are generated being one of the daily wastes emerging in dominant countries with high rate and big quantity. Escherichia coli BW25113 wild-type strain, mutants with defects in hydrogen (H2)-producing/oxidizing four hydrogenases (Hyd) (ΔhyaB ΔhybC, ΔhycE, ΔhyfG) and septuple mutant (ΔhyaB ΔhybC ΔhycA ΔfdoG ΔldhA ΔfrdC ΔaceE) were investigated by measuring change of external pH, bacterial growth and H2 production during the utilization of SCG hydrolysate. In wild type, H2 was produced with rate of 1.

Influence of C -Dcu transporters on hydrogenase and formate dehydrogenase activities in stationary phase-grown fermenting Escherichia coli.

During mixed-acid fermentation, Escherichia coli transports succinate mainly via transporters of the Dcu family. Here, we analyze the influence of Dcu transporters on hydrogenase (Hyd) and fermentative formate dehydrogenase (FDH-H) activities and how this is affected by external pH and carbon source. Using selected dcu mutations, it was shown that Dcu carriers mainly affect Hyd and FDH-H activities during glycerol but not glucose fermentation at acidic pH.

Formate and potassium ions affect Escherichia coli proton ATPase activity at low pH during mixed carbon fermentation.

Escherichia coli is able to ferment not only single but also mixtures of carbon sources. The formate metabolism and effect of formate on various enzymes have been extensively studied during sole glucose but not mixed carbon sources utilization. It was revealed that in membrane vesicles (MV) of wild type cells grown at pH 7.

Fermentation Revisited: How Do Microorganisms Survive Under Energy-Limited Conditions?

During fermentation FF hydrolyzes ATP, coupling proton transport to proton-motive force (pmf) generation. Despite that, pmf generated by ATP hydrolysis does not satisfy the energy budget of a fermenting cell. However, pmf can also be generated by extrusion of weak organic acids such as lactate and by hydrogen cycling catalyzed by hydrogenases (Hyds).

Understanding the Role of Escherichia coli Hydrogenases and Formate Dehydrogenases in the F F -ATPase Activity during the Mixed Acid Fermentation of Mixture of Carbon Sources.

During fermentation Escherichia coli produces di-hydrogen (H ) via reversible membrane-bound [Ni-Fe]-hydrogenases (Hyd). This study describes the total and N,N'-dicyclohexylcarbodiimide (DCCD) inhibited ATPase activity and H production at various pHs in E. coli wild type and mutants encoding Hyd enzymes and formate dehydrogenases (FDH) on fermentation of glucose, glycerol, and formate.

Millimeter waves or extremely high frequency electromagnetic fields in the environment: what are their effects on bacteria?

Millimeter waves (MMW) or electromagnetic fields of extremely high frequencies at low intensity is a new environmental factor, the level of which is increased as technology advance. It is of interest that bacteria and other cells might communicate with each other by electromagnetic field of sub-extremely high frequency range. These MMW affected Escherichia coli and many other bacteria, mainly depressing their growth and changing properties and activity.