Search

A water soluble diarylethene (DAE) derivative that displays exceptionally intense fluorescence from the colorless open form has been synthesized and characterized using UV/vis spectroscopy and fluorescence microscopy. We show that the bright emission from the open form can be rapidly switched using amplitude modulated red light, that is, by light at wavelengths longer than those absorbed by the fluorescent species. This is highly appealing in any context where undesired background fluorescence disturbs the measurement, e.g., the autofluorescence commonly observed in fluorescence microscopy. We show that this scheme is conveniently applicable using lock-in detection, and that robust amplitude modulation of the probe fluorescence is indeed possible also in cell studies using fluorescence microscopy., A water soluble diarylethene derivative displaying exceptionally bright fluorescence in the open isomeric form has been used for emission amplitude-modulation. We apply this scheme in fluorescence microscopy, aiming to suppress undesired background.

Background: Dexmedetomidine (DEX), an α2-adrenoceptor agonist, has been reported to possess neuroprotective effects against postoperative cognitive impairment. GLO-1 plays a key role in the pathogenesis of Alzheimer’s disease (AD). Here, the primary goal was to assess whether DEX affect GLO-1 and protect cognition impairment in APP/PS1 transgenic mice.Methods: After DEX was intraperitoneally injected in APP/PS1 mice, behavior was tested by Water Maze to illustrate whether DEX treatment has a significantly positive effect on ameliorating the cognition deficits in AD. We assessed the effect of DEX on the expression of GLO-1 and the production of other oxidative stress factors by ELISA and Western blot. To determine whether DEX play roles in the Aβ induced neuron apoptosis, flow cytometry was used.Results: DEX treatment significantly ameliorated cognition deficits in APP/PS1 mice. DEX increased GLO-1 expression and decreased MG activity in the hippocampus. In addition, DEX increased activity of SOD, GSH and reduced the activity of MDA. In vitro, DEX could protect the neuron apoptosis induced by Aβ. GLO-1 inhibitor could block the protective role of DEX.Conclusion: Taken together, our findings suggest that DEX prevents progression of AD-like pathology through upregulating GLO-1.

Additional file 5: Table S2. The raw data of fecal samples of BD and HH groups. BD, brisket disease. HH, healthy heifers.

On-command changes in the emission color of functional materials is a sought-after property in many contexts. Of particular interest are systems using light as the external trigger to induce the color changes. Here we report on a tri-component cocktail consisting of a fluorescent donor molecule and two photochromic acceptor molecules encapsulated in polymer micelles and we show that the color of the emitted fluorescence can be continuously changed from blue-to-green and from blue-to-red upon selective light-induced isomerization of the photochromic acceptors to the fluorescent forms. Interestingly, isomerization of both acceptors to different degrees allows for the generation of all emission colors within the red-green-blue (RGB) color system. The function relies on orthogonally controlled FRET reactions between the blue emitting donor and the green and red emitting acceptors, respectively., Stimuli-responsive multicolor luminescent materials typically react on external triggers of physical nature, but photonically controlled systems which allow for remote operation were not realized. Here the authors use light as the stimulus of a responsive luminescent material which eliminates the need for physical access.

Additional file 4: Table S1. Ingredient and nutrient concentrations of experimental diets.

A molecular cocktail containing two photochromic diarylethene derivatives that displays multicolor emission spanning blue-green to orange in a color-correlated fashion has been devised. The function does not rely on excited state communication such as energy transfer reactions, which is the typical case for similar systems. Instead, harnessing the intrinsic fluorescent and photochromic properties of the two individual diarylethene derivatives run in parallel is enough to realize the color changes. This offers an extremely flexible situation as for the choice of the fluorophores and their respective concentrations. The function is conveniently demonstrated in bulk solution at μM concentrations, where a single light source serves as the color changing stimulus.

To study the effects of organic compounds on the formation of silica, the polymerization of silicic acid in sodium silicate solutions in the presence and absence of sodium salicylate and disodium phthalate was investigated. The monosilicic acid concentration showed minor differences among the three different solutions. However, the concentration of polysilicic acid particles larger than 0.45 μm varied significantly among the three solutions, suggesting that the two organic compounds accelerate the growth of polysilicic acid. In particular, the concentration of polysilicic acid particles larger than 0.45 μm increased sharply in accordance with phthalate concentration, which is further evidence that phthalate accelerates the growth of silica. SEM images and size distribution measurements revealed that phthalate accelerates the aggregate of small silica particles to form larger silica pieces. FT-IR spectra of the silica formed during the polymerization of silicic acid showed the presence/or adsorption of salicylate and phthalate in the silica particles/or on the silica surfaces. The bidentate adsorption of salicylate or phthalate to two different polysilicic acid particles may accelerate the P–P reaction to aggregate the individual silica particles and rapidly form large size of silica.

Genetically engineered bacteria and reactive DNA networks detect edges of objects, as done in our retinas and as also found within computer vision. We now demonstrate that simple molecular logic systems (a combination of a pH sensor, a photo acid generator, and a pH buffer spread on paper) without any organization can achieve this relatively complex computational goal with good fidelity. This causes a jump in the complexity achievable by molecular logic-based computation and extends its applicability. The molecular species involved in light dose-driven "off-on-off" fluorescence is diverted in the "on" state by proton diffusion from irradiated to unirradiated regions where it escapes a strong quencher, thus visualizing the edge of a mask.

Campylobacter jejuni, an important foodborne microorganism, poses severe and emergent threats to human health as antibiotic resistance becomes increasingly prevalent. The mechanisms of drug resistance are hard to decipher, and little is known at the metabolic level. Here we apply metabolomic profiling to discover metabolic changes associated with amphenicol (chloramphenicol and florfenicol) resistance mutations of Campylobacter jejuni. An optimized sample preparation method was combined with ultra-high-performance liquid chromatography-time-of-flight mass spectrometry (UHPLC-TOF/MS) and pattern recognition for the analysis of small-molecule biomarkers of drug resistance. UHPLC-triple quadrupole MS operated in multiple reaction monitoring mode was used for quantitative analysis of metabolic features from UHPLC-TOF/MS profiling. Up to 41 differential metabolites involved in glycerophospholipid metabolism, sphingolipid metabolism, and fatty acid metabolism were observed in a chloramphenicol-resistant mutant strain of Campylobacter jejuni. A panel of 40 features was identified in florfenicol-resistant mutants, demonstrating changes in glycerophospholipid metabolism, sphingolipid metabolism, and tryptophan metabolism. This study shows that the UHPLC-MS-based metabolomics platform is a promising and valuable tool to generate new insights into the drug-resistant mechanism of Campylobacter jejuni.

Equilibrium studies were carried out for the adsorption of phosphate onto newly discharged coal gangue and spontaneous combustion coal gangue, which are industrial solid residues. The experimental data were fitted to the two-parameter equations of Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich and the three-parameter equations of the Redlich-Peterson, Sips and Toth isotherms by non-linear method. All three-parameter isotherm equations have a higher correlation coefficient than the two-parameter isotherm equations. For new discharged coal gangue, the maximum phosphate adsorption capacity is over 2.504 mg/g (as P), and the best two-parameter isotherm is Freundlich, which indicated multilayer adsorption takes place on the surface. For spontaneous combustion coal gangue, the maximum phosphate adsorption capacity is 7.079 mg/g (as P), two times larger than new discharged coal gangue, and the best two-parameter isotherm is Langmuir, suggesting that the adsorption process occurs on a homogenous surface by monolayer adsorption. The three-parameter isotherm model of Redlich-Peterson shows the best fitting in both cases, but parameter g is 0.6138 in new discharged coal gangue (the parameter g is nearly 1, which means that the equilibrium isotherm behaves as the Langmuir, not as the Freundlich isotherm), g approaches to unity in spontaneous combustion coal gangue, suggesting that the two kinds of coal gangues have different adsorption properties.

Herein, we report the first example of one-time password (OTP) generation and two-factor authentication (2FA) using a molecular approach. OTPs are passwords that are valid for one entry only. For the next login session, a new, different password is generated. This brings the advantage that any undesired recording of a password will not risk the security of the authentication process. Our molecular realization of the OTP generator is based on a photochromic molecular triad where the optical input required to set the triad to the fluorescent form differs depending on the initial isomeric state.

To evaluate the effect of organic compounds on the dissolution rate of amorphous silica, the dissolution of amorphous silica in pure water and in organic electrolyte solutions were investigated at room temperature at pH 6. Based on the kinetic analyses, the dissolution rate constants of amorphous silica in the organic electrolyte solutions were 18–30 times larger than in pure water but less than those in the NaCl solution, which contained the same Na+ concentration as the organic electrolyte solution. The order of dissolution rate constants was NNaCl > Ntiron > Nphthalate > Nsalicylate > Nwater. In these experiments, the dried samples were analyzed by FT-IR, and the results indicated that all of the organic composition was adsorbed on the surface of the silica. Compared with pure water, the cations in the organic electrolyte solution were a dominant factor in increasing the dissolution rate of silica. However, compared with NaCl, the dissolution rate of silica decreased in the aromatic organic electrolyte solution due to the adsorption of the organic electrolytes on the surface of the silica as well as to a decrease in the exposed surface. In fact, organic anions containing in the organic electrolytes are retarding the dissolution rate of silica.

The precipitations of calcium carbonate (CaCO3) from supersaturated solutions were investigated in the absence and presence of polysilicic acid under the condition of pH 9 at room temperature. The turbidity of the CaCO3 solution in the presence of polysilicic acid was lower than that in the absence of polysilicic acid, suggesting that the polysilicic acid inhibits the precipitation of CaCO3. The turbidity of solutions was distinctly decreased with increasing the polysilicic acid concentration. SEM images of the precipitates provide visual evidence that colloidal silica adhered to active growth sites of CaCO3 nucleus through electrostatic attraction to inhibit the growth of CaCO3 crystals.

Five ferruginous deposit samples formed from neutral hot springs were analyzed to determine whether they consisted of a mixture of silica, hydrous iron oxide or iron silicate by differential thermal analysis (DTA), infrared (IR) spectroscopy, powder X-ray diffraction (XRD), and 57Fe Mossbauer spectroscopy. The Si/Fe atomic ratios of the deposits ranged from 0.25 to 0.45, and were smaller than those of hisingerite (1–2), but apparently close to those of siliceous ferrihydrite (0.25–0.5). Si was confirmed to be present as monomeric or oligomeric silicate from the Si-O stretching vibration frequencies on the IR spectra. Judging from the results of DTA, which minerals starting to produce after heating, and a relationship between Si-O stretching vibration frequency and Si/Fe atomic ratio proposed by Henmi et al. (1981), all the deposits in this study were concluded to be mixtures of various siliceous ferrihydrites with low and high Si/Fe atomic ratios. Moreover, by comparing the chemical properties of hot spring waters, the formation conditions of siliceous ferrihydrite were also discussed.

Bacterial antibiotic efflux pumps are key players in antibiotic resistance. Although their role in conferring multidrug resistance is well documented, the emergence of “super” efflux pump variants that enhance bacterial resistance to multiple drugs has not been reported. Here, we describe the emergence of a resistance-enhancing variant (named RE-CmeABC) of the predominant efflux pump CmeABC in Campylobacter, a major zoonotic pathogen whose resistance to antibiotics is considered a serious antibiotic resistance threat in the United States. Compared to the previously characterized CmeABC transporters, RE-CmeABC is much more potent in conferring Campylobacter resistance to antibiotics, which was shown by increased MICs and reduced intracellular accumulation of antibiotics. Structural modeling suggests that sequence variations in the drug-binding pocket of CmeB possibly contribute to the enhanced efflux function. Additionally, RE-CmeABC expands the mutant selection window of ciprofloxacin, enhances the emergence of antibiotic-resistant mutants, and confers exceedingly high-level resistance to fluoroquinolones, an important class of antibiotics for clinical therapy of campylobacteriosis. Furthermore, RE-CmeABC is horizontally transferable, shifts antibiotic MIC distribution among clinical isolates, and is increasingly prevalent in Campylobacter jejuni isolates, suggesting that it confers a fitness advantage under antimicrobial selection. These findings reveal a new mechanism for enhanced multidrug resistance and an effective strategy utilized by bacteria for adaptation to selection from multiple antibiotics., IMPORTANCE Bacterial antibiotic efflux pumps are ubiquitously present in bacterial organisms and protect bacteria from the antibacterial effects of antimicrobials and other toxic compounds by extruding them out of cells. Thus, these efflux transporters represent an important mechanism for antibiotic resistance. In this study, we discovered the emergence and increasing prevalence of a unique efflux pump variant that is much more powerful in the efflux of antibiotics and confers multidrug resistance in Campylobacter, which is a major foodborne pathogen transmitted to humans via the food chain. Unlike other specific resistance determinants that only allow bacteria to resist a particular antimicrobial, the acquisition of a functionally enhanced efflux pump will empower bacteria with simultaneous resistance to multiple classes of antibiotics. These findings reveal a previously undescribed mechanism for enhanced multidrug resistance and open a new direction for us to understand how bacteria adapt to antibiotic treatment.

To elucidate the mechanism of silica biodeposition in hot spring water, which is induced by Al 3+ ions bound to the surface of microbes, a chelate resin (Chelex 100) was used as a model compound of the surface of microbes. No silicic acid was adsorbed on the Na type Chelex 100, whereas silicic acids were significantly adsorbed to the Al type Chelex 100. In the Al type Chelex 100, the Al 3+ ions were present as 1:1 tridentate complex with iminodiacetate (IDA) group. After adsorption of silicic acid to Al type Chelex 100, a IDA Al O Si (OH) 3 site formed. The site acted as a template for the successive adsorption of silicic acids to form silica sheets around Al type Chelex 100 particles. In conclusion, Al 3+ ions bound to the surface of microbes play a key role as a trigger for the biodeposition of silica in hot spring water.

This study elucidates the effect of zinc (Zn), which is an anticorrosive water additive, on the formation of silica scales from cooling water. In these experiments, the silica scales were analyzed by EPMA, and the results indicate that Zn is sorbed into the silica scales during formation. Measurements of the solubility of Zn(OH)(2) at various concentrations of silicic acid demonstrate that Zn is present as a silicato complex of Zn (SCZ) in cooling water. From adsorption experiments of the SCZ on silica and alumina, which are major components of the silica scales, it can be concluded that the SCZ accelerates the formation of silica scales from cooling water.

The recently-discovered ability of small logical molecules to recognize edges is exploited to achieve outline drawing from binary templates. Outlines of arbitrary curvature, several colours and thicknesses down to 1 mm are drawn in around 30 min or less by employing a common laboratory two-colour ultraviolet lamp. The outlines and the light dose-driven XOR logic with fluorescence output or ‘off–on–off’ action which is observed in the irradiated regions are modelled by combining foundational principles of photochemistry, acid–base neutralization and diffusion.

Molecular logic-based computation continues to throw up new applications in sensing and switching, the newest of which is the edge detection of objects. The scope of this phenomenon is mapped out by the use of structure–activity relationships, where several structures of the molecules and of the objects are examined. The different angles and curvatures of the objects are followed with good fidelity in the visualized edges, even when the objects are in reverse video.

Objectives This study was conducted to examine the development and molecular mechanisms of amphenicol resistance in Campylobacter jejuni by using in vitro selection with chloramphenicol and florfenicol. The impact of the resistance development on growth rates was also determined using in vitro culture. Methods Chloramphenicol and florfenicol were used as selection agents to perform in vitro stepwise selection. Mutants resistant to the selective agents were obtained from the selection process. The mutant strains were compared with the parent strain for changes in MICs and growth rates. The 23S rRNA gene and the L4 and L22 ribosomal protein genes in the mutant strains and the parent strain were amplified and sequenced to identify potential resistance-associated mutations. Results C. jejuni strains that were highly resistant to chloramphenicol and florfenicol were obtained from in vitro selection. A novel G2073A mutation in all three copies of the 23S rRNA gene was identified in all the resistant mutants examined, which showed resistance to both chloramphenicol and florfenicol. In addition, all the mutants selected by chloramphenicol also exhibited the G74D modification in ribosomal protein L4, which was previously shown to confer a low-level erythromycin resistance in Campylobacter species. The mutants selected by florfenicol did not have the G74D mutation in L4. Notably, the amphenicol-resistant mutants also exhibited reduced susceptibility to erythromycin, suggesting that the selection resulted in cross resistance to macrolides. Conclusions This study identifies a novel point mutation (G2073A) in 23S rRNA in amphenicol-selected mutants of C. jejuni. Development of amphenicol resistance in Campylobacter likely incurs a fitness cost as the mutant strains showed slower growth rates in antibiotic-free media.

To study the anti-inflammatory mechanism of geniposide and observe the effect of geniposide on the expression of Toll-like receptor 4 (TLR4), the activity of NF-κB, and the release of pro-inflammatory cytokines- TNF-α, IL-1, and IL-6-in the RAW264.7 macrophages treated with lipopolysaccharide (LPS).There were three experimental groups, including the control group, LPS group and LPS combined with geniposide group in this study. RAW264.7 macrophage cells were treated with LPS to induce cellular inflammation. Cell proliferation was measured by CCK-8. The concentrations of TNF-α, IL-1, and IL-6 in cell culture media were measured by ELISA. mRNA levels of TLR4 and P65 were examined by real-time PCR. The protein levels of p-IκB, P65, p-P65 and TLR4 were detected by Western blotting.Geniposide had no effect on cell proliferation. However, geniposide down-regulated the expression of TNF-α, IL-1, and IL-6, and also inhibited the expression of TLR4 and the activity of NF-κB.Geniposide exerts its anti-inflammatory effect through inhibiting the activity of NF-κB in the TLR4-NF-κB pathway in macrophages.

As part of a series of studies on the interaction between ferric ions and silicic acid in the hydrosphere, the adsorption of silicic acid on akaganeite was investigated kinetically at various pH values. The adsorption of silicic acid increased with increasing pH over an initial pH range of 4-11.5. In the kinetic experiment, the Cl(-) was released from akaganeite much faster than silicic acid was adsorbed. From this result, we concluded that chloride ions bound on the surface of akaganeite are released and Fe-OH or Fe-O(-) sites are formed, which then acts as an adsorption site for silicic acid. The uptake mechanism of silicic acid by akaganeite is significantly different from that by schwertmannite, despite the presence of the same tunnel structure.

To prevent the silica scale formation in the geothermal water recycling process, the silicic acid perfectly removed from geothermal water as calcium silicate by calcium nitrate. Ordered mesoporous silica was synthesized at strong acidic condition by using low cost calcium silicate as silicon source, which was separated from geothermal water recycling process.