Addition Of Adenosine Triphosphate Research Articles

Development of a rhodamine-based fluorescent probe for ATP detection for potential applications in meat freshness assessment

Adenosine triphosphate (ATP) plays a vital role in physiological processes and is an essential indicator of microbial content in food. Herein, a new sensitive, rapid and water-soluble probe for ATP detection was developed. Rhodamine B and pentaethylenehexamine were employed to design and synthesise the probe rhodamine-pentaethylenehexamine (RP) for selective ATP detection. The synthesised probe RP was characterized using Fourier transform infrared, NMR and dynamic light scattering size distributions. Upon the addition of ATP, the probe exhibited a distinct change in fluorescence intensity, with fluorescence emission at 580 nm. A linear relationship was observed between fluorescence intensity and ATP concentrations at 0–50 μmol/L, with a limit of detection of 10.97 × 10−9 mol/L. The results of the zeta potential and molecular dynamics simulation demonstrated that the detection mechanism of the probe RP is associated with the electrostatic adsorption interaction between the multi-positively charged sites of RP and the negatively charged triphosphate structure of ATP. Our study provides new insights into improving charge site identification in small molecule detection. Furthermore, the successful detection of ATP on meat surfaces indicates that RP has the potential to assess meat freshness.

Understanding and fine tuning the propensity of ATP-driven liquid-liquid phase separation with oligolysine.

Liquid-liquid phase separation (LLPS) plays a pivotal role in the organization and functionality of living cells. It is imperative to understand the underlying driving forces behind LLPS and to control its occurrence. In this study, we employed coarse-grained (CG) simulations as a research tool to investigate systems comprising oligolysine and adenosine triphosphate (ATP) under conditions of various ionic concentrations and oligolysine lengths. Consistent with experimental observations, our CG simulations captured the formation of LLPS upon the addition of ATP and tendency of dissociating under high ionic concentration. The electrostatic interaction between oligolysine and ATP is of great importance in forming LLPS. An in-depth analysis on the structural properties of LLPS was conducted, where the oligolysine structure remained unchanged with increased ionic concentration and the addition of ATP led to a more pronounced curvature, aligning with the observed enhancement of α-helical secondary structure in experiments. In terms of the dynamic properties, the introduction of ATP led to a significant reduction in translational and vibrational degrees of freedom but not rotational degrees of freedom. Through keeping the total number of charged residues constant and varying their entropic effects, we constructed two systems of similar biochemical significance and further validated the entropy effects on the LLPS formation. These findings provide a deeper understanding of LLPS formation and shed lights on the development of novel bioreactor and primitive artificial cells for synthesizing key chemicals for certain diseases.

How ATP suppresses the fibrillation of amyloid peptides: analysis of the free-energy contributions.

Recent experiments have revealed that adenosine triphosphate (ATP) suppresses the fibrillation of amyloid peptides - a process closely linked to neurodegenerative diseases such as Alzheimer's and Parkinson's. Apart from the adsorption of ATP onto amyloid peptides, the molecular understanding is still limited, leaving the underlying mechanism for the fibrillation suppression by ATP largely unclear, especially in regards to the molecular energetics. Here we provide an explanation at the molecular scale by quantifying the free energies using all-atom molecular dynamics simulations. We found that the changes of the free energies due to the addition of ATP lead to a significant equilibrium shift towards monomeric peptides in agreement with experiments. Despite ATP being a highly charged species, the decomposition of the free energies reveals that the van der Waals interactions with the peptide are decisive in determining the relative stabilization of the monomeric state. While the phosphate moiety exhibits strong electrostatic interactions, the compensation by the water solvent results in a minor, overall Coulomb contribution. Our quantitative analysis of the free energies identifies which intermolecular interactions are responsible for the suppression of the amyloid fibril formation by ATP and offers a promising method to analyze the roles of similarly complex cosolvents in aggregation processes.

Ratiometric Fluorescent Detection of Ultrasound-Regulated ATP Release: An Ultrasound-Resistant Cu,N-Doped Carbon Nanosphere.

Focused ultrasound, as a protocol of cancer therapy, might induce extracellular adenosine triphosphate (ATP) release, which could enhance cancer immunotherapy and be monitored as a therapeutic marker. To achieve an ATP-detecting probe resistant to ultrasound irradiation, we constructed a Cu/N-doped carbon nanosphere (CNS), which has two fluorescence (FL) emissions at 438 and 578 nm to detect ultrasound-regulated ATP release. The addition of ATP to Cu/N-doped CNS was conducted to recover the FL intensity at 438 nm, where ATP enhanced the FL intensity probably via intramolecular charge transfer (ICT) primarily and hydrogen-bond-induced emission (HBIE) secondarily. The ratiometric probe was sensitive to detect micro ATP (0.2-0.6 μM) with the limit of detection (LOD) of 0.068 μM. The detection of ultrasound-regulated ATP release by Cu,N-CNS/RhB showed that ATP release was enhanced by the long-pulsed ultrasound irradiation at 1.1 MHz (+37%, p < 0.01) and reduced by the short-pulsed ultrasound irradiation at 5 MHz (-78%, p < 0.001). Moreover, no significant difference in ATP release was detected between the control group and the dual-frequency ultrasound irradiation group (+4%). It is consistent with the results of ATP detection by the ATP-kit. Besides, all-ATP detection was developed to prove that the CNS had ultrasound-resistant properties, which means it could bear the irradiation of focused ultrasound in different patterns and detect all-ATP in real time. In the study, the ultrasound-resistant probe has the advantages of simple preparation, high specificity, low limit of detection, good biocompatibility, and cell imaging ability. It has great potential to act as a multifunctional ultrasound theranostic agent for simultaneous ultrasound therapy, ATP detection, and monitoring.

Effects of ATP on the Physicochemical Properties and Cytocompatibility of Calcium Sulfate/Calcium Citrate Composite Cement.

Adenosine triphosphate (ATP), acting as a source of energy, has effects on cellular activities, such as adhesion, proliferation, and differentiation. In this study, ATP-loaded calcium sulfate hemihydrate/calcium citrate tetrahydrate cement (ATP/CSH/CCT) was successfully prepared for the first time. The effect of different contents of ATP on the structure and physicochemical properties of ATP/CSH/CCT was also studied in detail. The results indicated that incorporating ATP into the cement did not significantly alter their structures. However, the addition ratio of ATP directly impacted the mechanical properties and in vitro degradation properties of the composite bone cement. The compressive strength of ATP/CSH/CCT gradually decreased with an increasing ATP content. The degradation rate of ATP/CSH/CCT did not significantly change at low concentrations of ATP, but it increased with a higher ATP content. The composite cement induced the deposition of a Ca-P layer in a phosphate buffer solution (PBS, pH = 7.4). Additionally, the release of ATP from the composite cement was controlled. The ATP was controlled releasing at the 0.5% and 1% ATP in cement by the diffusion of ATP and the degradation of the cement, whereas it was controlled by the diffusion process merely at the 0.1% ATP in cement. Furthermore, ATP/CSH/CCT demonstrated good cytoactivity with the addition of ATP and is expected to be used for the repair and regeneration of bone tissue.

Near-Infrared Fluorescent Nanoprobes for Adenosine Triphosphate-Guided Imaging in Cancer and Fatty Liver Mice.

Adenosine triphosphate (ATP), as an indispensable biomolecule, is the main energy source of cells and is used as a marker for diseases such as cancer and fatty liver. It is of great significance to design a near-infrared fluorescent nanoprobe with excellent performance and apply it to various disease models. Here, a near-infrared fluorescent nanoprobe (ZIF-90@SiR) based on a zeolitic imidazole framework is proposed. The fluorescent nanoprobes are synthesized by encapsulating the dye (SiR) into the framework of ZIF-90. Upon the addition of ATP, the structure of the ZIF-90@SiR nanoprobe is disrupted and SiR is released to generate near-infrared fluorescence at 670 nm. In the process of ATP detection, ZIF-90@SiR shows high sensitivity and good selectivity. Moreover, the ZIF-90@SiR nanoprobe has good biocompatibility due to its low toxicity to cells. It is used for fluorescence imaging of ATP in living cells and thus distinguishing normal cells and cancer cells, as well as distinguishing fatty liver cells. Due to excellent near-infrared fluorescence properties, the ZIF-90@SiR nanoprobe can not only distinguish normal mice and tumor mice but also differentiate normal mice and fatty liver mice for the first time.

Biomass-Based Carbon Dots for Fe3+ and Adenosine Triphosphate Detection in Mitochondria

Real-time live-cell monitoring of Fe3+ and adenosine triphosphate (ATP) in mitochondria important for cellular functions and related to different diseases is highly desired, yet lack study. Herein, carbon dots, green bean (GB)-carbon dots (CDs), were made from GB through easy one-step hydrothermal treatment. GB-CDs were in spherical form with a diameter of 13 ± 3 nm, negatively charged, and green emissive. GB-CDs contained amino groups, which enabled their binding to Fe3+, resulting in their fluorescence quenching. Based on this, GB-CDs were employed to detect Fe3+ with high selectivity, showing a linear detection range of 10–70 μM and a detection limit of 3.6 nM. Furthermore, the addition of ATP can recover the fluorescence quenching of GB-CDs by Fe3+. Therefore, the GB-CD + Fe3+ system was deployed to assay ATP with a linear detection range of 50–600 μM and a detection limit of 60 nM, exhibiting high sensitivity and specificity. GB-CDs and GB-CDs + Fe3+ were individually harnessed to assess Fe3+ in tap water and ATP in fetal bovine serum. More importantly, GB-CDs can enter cells to localize in mitochondria for mitochondrial imaging with high biocompatibility and superior photostability. As a result, GB-CDs and GB-CD + Fe3+ system were implemented to track Fe3+ and ATP in mitochondria of A549, respectively. This study provides a potent tool to monitor Fe3+ and ATP in mitochondria, expanding the application of CDs as biosensors for biological compounds in subcellular organelles.

Phosphorylation-Driven Production of d-Allulose from d-Glucose by Coupling with an ATP Regeneration System.

d-Allulose is a desirable sucrose substitute with potential applications in food and health care. d-Allulose can be synthesized using d-glucose as a substrate through coupling glucose isomerase with d-allulose 3-epimerase (DAEase); however, the product yield is typically less than 20% at reaction equilibrium and thus limits its use in industrial applications. Here, a 3R-ketose phosphorylation pathway coupled with an adenosine triphosphate (ATP) regeneration system was developed for the efficient synthesis of d-allulose in Escherichia coli using d-glucose as a substrate. The l-rhamnulose kinase (RhaB) was used to break the inherent reaction equilibrium due to its substrate specificity, resulting in increases in d-allulose titer by 69.9% to 4.96 ± 0.49 g/L. By optimizing the whole cell transformation conditions and designing an ATP regeneration module, d-allulose production reached 17.62 ± 0.77 g/L from 30 g/L d-glucose with a final yield of 0.73 g/g without the addition of exogenous ATP. To evaluate the potential industrial application of this multienzyme cascade system, d-allulose was produced from cane molasses (124.16 ± 2.69 g/L glucose equivalent) with a final d-allulose titer of 62.60 ± 3.76 g/L. The present study provides a practical enzymatic approach for the economical synthesis of d-allulose.

Exploring the internal driving mechanism underlying bacterial community-induced organic component conversion and humus formation during rice straw composting with tricarboxylic acid cycle regulator addition

The aim of this study was to investigate the effect of tricarboxylic acid (TCA) cycle regulators on CO2 emissions, the conversion of organic components and humus formation during composting. The addition of adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide (NADH) reduced CO2 emissions during rice straw composting. According to co-occurrence networks results, ATP enhanced the connectivity and complexity of the network; NADH enhanced microbial interactions. The different kind of TCA cycle regulators had different effect on humus formation pathway. The structural equation model showed that ATP might promote lignin transformation into humus via the sugar-amine condensation pathway and lignin-protein pathway while NADH may promote cellulose degradation into soluble sugar and organic matter, which are transformed into humus. This work will provide valuable guidance for exploring the mechanism of TCA cycle regulators in promoting organic carbon fixation and reducing inorganic carbon mineralization.

SMC complexes can traverse physical roadblocks bigger than their ring size.

Ring-shaped structural maintenance of chromosomes (SMC) complexes like condensin and cohesin extrude loops of DNA. It remains, however, unclear how they can extrude DNA loops in chromatin that is bound with proteins. Here, we use invitro single-molecule visualization to show that nucleosomes, RNA polymerase, and dCas9 pose virtually no barrier to loop extrusion by yeast condensin. We find that even DNA-bound nanoparticles as large as 200nm, much bigger than the SMC ring size, also translocate into DNA loops during extrusion by condensin and cohesin. This even occurs for a single-chain version of cohesin in which the ring-forming subunits are covalently linked and cannot open to entrap DNA. The data show that SMC-driven loop extrusion has surprisingly little difficulty in accommodating large roadblocks into the loop. The findings also show that the extruded DNA does not pass through the SMC ring (pseudo)topologically, hence pointing to a nontopological mechanism for DNA loop extrusion.

Aedes aegypti (L.) and Anopheles stephensi Liston (Diptera: Culicidae) Susceptibility and Response to Different Experimental Formulations of a Sodium Ascorbate Toxic Sugar Bait.

Attractive toxic sugar baits (ATSBs) require target insects to locate, orient toward, and feed on an insecticidal sugar solution to control populations. Formulating these baits with different attractants and phagostimulants can increase their efficacy by causing insects to choose the ATSB over competing natural sugar sources, and to ingest more of the bait solution. We tested formulations of a 20% sodium ascorbate (SA) ATSB solution using different sugars, adenosine triphosphate (ATP), gallic acid, and six plant volatile compounds to determine their effect on adult Aedes aegypti (L.) and Anopheles stephensi Liston mortality. Baits formulated with fructose or sucrose had no effect on either species, neither did the addition of ATP. Gallic acid increased the survival of Ae. aegypti. Four of the six volatile compounds increased mortality in at least one species. We also examined An. stephensi response to baits formulated with each of the six volatile compounds. Anisaldehyde significantly increased the number of mosquitoes responding toward the SA-ATSB, but increasing the amount had no effect. Addition of anisaldehyde also significantly increased An. stephensi feeding rates on the SA-ATSB, though mosquitoes will avoid the toxic bait if a nontoxic sugar source is available. Formulation of SA-ATSBs with synthetic blends of attractive compounds can increase bait efficacy and consistency, though further research is needed to assess their performance in the field in the presence of natural sugar sources.

Biocompatible Chemically Fueled Transient Polymer Nanoparticles for Temporally Programmable in Vivo Imaging

Biocompatible Chemically Fueled Transient Polymer Nanoparticles for Temporally Programmable in Vivo Imaging

MO247: Exogen ATP has a Suppressive Effect on CD4+-T-Cells In Aav-Patients And Healthy Controls

Abstract BACKGROUND AND AIMS Anti-neutrophil-cytoplasmatic-antibody-associated vasculitis (AAV) is a life-threatening autoimmune disease. It is a necrotizing vasculitis of small- and medium-sized vessels. T-cells play a pivotal role in pathogenesis and mediating damage in the vessels. Exogen ATP (adenosine triphosphate) is normally in a low nanomolar range. Under inflammatory conditions, various cells can release ATP to the extracellular department. In this case, ATP is a DAMP (damage-associated molecular pattern), but its effect on disease mechanisms in AAV is not well understood. It is the aim of the study to determine the effect of exogenous ATP on T-cells in healthy controls and AAV-patients. METHOD A total of 22 AAV-patients in remission and 13 healthy controls were recruited. Peripheral blood mononuclear cells (PBMC) were isolated and then labeled with a tracking dye. The PBMC were cultured for 3 days with different concentrations of ATP in presence or absence of anti-CD3/CD28 stimulation. After 3 days, the cells were restimulated with PMA/Ionomycin and Brefeldin A for 4 hours. Cytokine production and cell proliferation were assessed by flow cytometry. Baseline was defined as T-cell proliferation in absence of exogenous ATP. The fold change was calculated by: $\frac{{{\rm{T}} - {\rm{cell\ proliferation\ with\ ATP}}}}{{{\rm{T}} - {\rm{cell\ proliferation\ without\ ATP}}}}$ . The P-value for paired values was calculated by the Wilcoxon matched-pairs signed rank test. The P-value for unpaired groups was calculated by the Mann Whitney U-test. RESULTS The mean T-cell proliferation of CD4+-T-cells for healthy controls was significantly different comparing 0 µM ATP and 500 µM ATP (mean proliferated fraction, 0 µM ATP versus 500 µM ATP: 40.48% versu 22.58%, P = .0002). In presence of ATP, a suppression of T-cell proliferation was found in patients and healthy controls (patients versus healthy controls, fold change T-cell proliferation from baseline with 50 µM ATP: 0.81 ± 0.03 versus 0.79 ± 0.03, P = .60; 125 µM ATP: 0.75 ± 0.03 versus 0.70 ± 0.04, P = .38; 250 µM ATP: 0.68 ± 0.03 versus 0.59 ± 0.05, P = .17; 500 µM ATP: 0.53 ± 0.03 versus 0.54 ± 0.05, P = .77); the higher the concentration of ATP, the stronger the suppression of proliferation. IFNγ+-CD4+-T-cells of healthy controls were also suppressed by exogenous ATP (0 µM ATP versus 500 µM ATP, CD4+ T-cells: %IFNγ+: 19.94% versus 10.59%, P = .0002). INFγ production by CD4+-T-cells was reduced after addition of ATP in both patients and healthy controls (patients versus healthy controls, fold change CD4+-IFNγ+ -T-cells from baseline with 50 µM ATP: 0.69 ± 0.04 versus 0.64 ± 0.04, P = 0.45; 125 µM ATP: 0.62 ± 0.04 versus 0.58 ± 0.04, P = .63; 250 µM ATP: 0.62 ± 0.04 versus 0.49 ± 0.04, P = .11; 500 µM ATP: 0.59 ± 0.05 versus 0.51 ± 0.05, P = .56). CONCLUSION Exogenous ATP induced suppression of T-cells in healthy controls and might be important for the maintenance of immunotolerance. DAMP-mediated inhibitory mechanisms were functional in AAV-patients in remission.

Extracellular phosphoprotein regulation is affected by culture system scale-down

BackgroundPhosphorylated proteins are known to be present in multiple body fluids in normal conditions, and abnormally accumulated under some pathological conditions. The biological significance of their role in the extracellular space has started being elucidated only recently, for example in bone mineralization, neural development, and coagulation. Here, we address some criticalities of conventional culture systems for the study of the extracellular regulation of phosphorylation. MethodsWe make use of microfluidics to scale-down the culture volume to a size comparable to the interstitial spaces occurring in vivo. The phosphoprotein content of conditioned media was analyzed by a colorimetric assay that detects global phosphorylation. ResultsWe found that miniaturization of the culture system increases phosphoprotein accumulation. Moreover, we demonstrated that in conventional culture systems dilution affects the extent of the phosphorylation reactions occurring within the extracellular space. On the other hand, in microfluidics the phosphorylation status was not affected by addition of adenosine triphosphate (ATP) and FAM20C Golgi Associated Secretory Pathway Kinase (FAM20C) ectokinase, as if their concentration was already not limiting for the phosphorylation reaction to occur. ConclusionsThe volume of the extracellular environment plays a role in the process of extracellular phosphorylation due to its effect on the concentration of substrates, enzymes and co-factors. General significanceThus, the biological role of extracellular phosphoregulation may be better appreciated within a microfluidic culture system.

A fluorescence nanoplatform for the determination of hydrogen peroxide and adenosine triphosphate via tuning of the peroxidase-like activity of CuO nanoparticle decorated UiO-66.

A novel nanocomposite of CuO nanoparticle-modified Zr-MOF (CuO/UiO-66) was synthesized and developed as a fluorescence nanoplatform for H2O2 and adenosine triphosphate (ATP) via the "turn-on-off" mode in the presence of terephthalic acid (TA). The structure of CuO/UiO-66 was thoroughly characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and other techniques. The CuO/UiO-66 with enhanced peroxidase-like (POD) activity obtained due to the Zr4+ in UiO-66 is beneficial to the aggregation of CuO NPs on its surface. As a result, the strengthened fluorescence at 425nm with the excitation of 300nm wasfound due to the highly fluorescent species of TAOH. This isproduced bythe oxidation of TA by ·OH that came from the catalysis of H2O2 via the peroxidase mimic of CuO/UiO-66. Hence the modification of CuO NPs on porous UiO-66 can provide a friendly and sensitive physiological condition for H2O2 detection. However, upon addition of ATP, the fluorescence intensity of TAOH at 425nm effectively declined owing to the formation of complexation of Zr4+-ATP and the interaction of CuO to ATP which hampers the catalytic reaction of CuO/UiO-66 to H2O2. Thespecific interaction induced "inhibition of the peroxide-like activity" endows the sensitive and selective recognition of ATP. The detection limits were 16.87 ± 0.2nM and 0.82 ± 0.1nM, and linear analytical ranges were 0.02-100μM and 0.002-30μM for H2O2 and ATP, respectively. The novel strategy was successfully applied toH2O2 and ATP determination in serum samples with recoveries of 97.2-103.8% for H2O2 and 97.6-101.7% for ATP, enriching the avenue to design functional MOFs and providing new avenue of multicomponent bioanalysis.

Mitochondrial homeostasis regulates definitive endoderm differentiation of human pluripotent stem cells

Cellular organelles play fundamental roles in almost all cell behaviors. Mitochondria have been reported to be functionally linked to various biological processes, including reprogramming and pluripotency maintenance. However, very little about the role of mitochondria has been revealed in human early development and lineage specification. Here, we reported the characteristics and function of mitochondria during human definitive endoderm differentiation. Using a well-established differentiation system, we first investigated the change of mitochondrial morphology by comparing undifferentiated pluripotent stem cells, the intermediate mesendoderm cells, and differentiated endoderm cells, and found that mitochondria were gradually elongated and matured along differentiation. We further analyzed the expression pattern of mitochondria-related genes by RNA-seq, indicating that mitochondria became active during differentiation. Supporting this notion, the production of adenosine triphosphate (ATP) and reactive oxygen species (ROS) was increased as well. Functionally, we utilized chemicals and genome editing techniques, which could interfere with mitochondrial homeostasis, to determine the role of mitochondria in human endoderm differentiation. Treatment with mitochondrial inhibitors, or genetic depletion of mitochondrial transcription factor A (TFAM), significantly reduced the differentiation efficiency of definitive endoderm. In addition, the defect in endoderm differentiation due to dysfunctional mitochondria could be restored to some extent by the addition of ATP. Moreover, the clearance of excessive ROS due to dysfunctional mitochondria by N-acetylcysteine (NAC) improved the differentiation as well. We further found that ATP and NAC could partially replace the growth factor activin A for definitive endoderm differentiation. Our study illustrates the essential role of mitochondria during human endoderm differentiation through providing ATP and regulating ROS levels, which may provide new insight for metabolic regulation of cell fate determination.

Visual Detection of Adenosine Triphosphate by Taylor Rising: A Simple Point-of-Care Testing Method Based on Rolling Circle Amplification.

Rapid and sensitive point-of-care testing (POCT) is an extremely critical mission in practical applications, especially for rigorous military medicine, home health care, and in the third world. Here, we report a visual POCT method for adenosine triphosphate (ATP) detection based on Taylor rising in the corner of quadratic geometries between two rod surfaces. We discuss the principle of Taylor rising, demonstrating that it is significantly influenced by contact angle, surface tension, and density of the sample, which are controlled by ATP-dependent rolling circle amplification (RCA). In the presence of ATP, RCA reaction effectively suppresses Taylor-rising behavior, due to the increased contact angle, density, and decreased surface tension. Without addition of ATP, untriggered RCA reaction is favorable for Taylor rising, resulting in a significant height. With this proposed method, visual sensitive detection of ATP without the aid of other instruments is realized with only a 5 μL droplet, which has good selectivity and a low detection limit (17 nM). Importantly, this visual method provides a promising POCT tool for user-friendly molecular diagnostics.

The Antifungal Activity of Loquat (Eriobotrya japonica Lindl.) Leaves Extract Against Penicillium digitatum.

This study was performed to determine the antifungal activity of loquat (Eriobotrya japonica Lindl) leaf extract (LLE) against the citrus postharvest pathogen Penicillium digitatum (P. digitatum). The LLE exhibited an antifungal activity against P. digitatum, with a minimum inhibitory concentration (MIC) of 0.625 mg/ml and a minimum fungicidal concentration (MFC) of 1.25 mg/ml. Significant inhibitory effects of LLE on mycelial growth and spore germination of P. digitatum were seen in a dose-dependent manner. Simultaneously, to investigate possible antifungal mechanisms by LLE, we analyzed their influence on morphological changes, cell membrane permeability, cell wall and cell membrane integrity, and adenosine phosphates (ATP, ADP, and AMP) levels. Alterations, such as sunken surface and malformation, occurred in the LLE-treated P. digitatum spores. Furthermore, intracellular inclusion content decreased after LLE treatment, indicating an increase in cell membrane permeability. Besides, the LLE treatment induced a significant decline in the level of adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP) with a noticeable addition of extracellular ATP, ADP, and AMP during the entire treatment period. Overall, the results manifested that the antifungal activity of LLE against P. digitatum can be attributed to the derangement of cell membrane permeability and disordered energy metabolism. This is the first report on the mechanism of antifungal activity of LLE and could be useful in the development of targeted fungicides from natural origin.

A Novel Fluorescent Probe for ATP Detection Based on Synergetic Effect of Aggregation-induced Emission and Counterion Displacement

In this work, a fluorescent probe(TPEBe-I) was developed for adenosine triphosphate(ATP) detection based on the synergetic effect of aggregation-induced emission and counterion displacement. TPEBe-I gave weak emission in aqueous solution due to the heavy-atom effect of counter iodide ion. However, upon the addition of ATP, the new aggregate complex(TPEBe-ATP) was formed between the cationic unit of TPEBe-I and ATP through electrostatic interactions, which not only restricted the intramolecular motion of luminogen but also eliminated the quenching effect of iodide ion. As a result, the fluorescent light-up detection for ATP was successfully achieved. Moreover, TPEBe-I exhibited high selectivity towards ATP and showed a wide linear detection region towards the logarithm of ATP concentration(5—600 µmol/L) with a detection limit of 1.0 µmol/L, enabling TPEBe-I as a promising probe for ATP quantitative analysis.

Vacuolar compartmentalisation and efflux of cadmium in barley

Plants have developed different tolerance strategies to deal with toxic metals. Various factors and mechanisms related to the compartmentalisation of cadmium (Cd) into the vacuoles and the efflux of Cd were investigated to analyse their roles in Cd tolerance in barley. In vacuolar transport assays, the addition of adenosine triphosphate (ATP) alone significantly increased Cd uptake into the vacuole, but more so when both ATP and glutathione (GSH) were supplied together. This suggests that Cd may be partly sequestered as Cd2+ ions via divalent cation transporters, but predominantly as Cd–GSH complexes, most likely via ATP-binding cassette transporter-type transporters. Comparison of the concentrations of 109Cd in whole protoplasts and vacuoles isolated from shoots demonstrated that the majority of the cellular Cd was located in the vacuole. Over 48 h, 12% of the root Cd was effluxed into the external solution when roots were loaded with 109Cd by foliar application. This active excretion may be a detoxification strategy, in addition to the compartmentalisation of the majority of cellular cadmium into vacuoles predominantly as complexed form.