Investigating the impacts of airborne dust on herbicide performance on Amaranthus retroflexus.

Dust pollution poses environmental hazards, affecting agriculture through reduced sunlight exposure, photosynthesis, crop yields, and food security. This study explores the interference of dust pollution on herbicide efficacy to control weeds in a semi-arid region. In a factorial experiment conducted in 2019 and replicated in 2020, the interaction of dust and various herbicide applications, including bentazon, sulfosulfuron, tribenuron-methyl, aminopyralid + florasulam, foramsulfuron + iodosulfuron + thiencarbazone, 2,4-D + MCPA, and acetochlor, in controlling Amaranthus retroflexus L. were assessed. Dust induced a 9.2% reduction in the total chlorophyll content of A. retroflexus, while herbicide application independently led to a 67.5% decrease. Contrary to expectations, herbicides performed better in dust, except bentazon, which caused a 28% drop in plant height and a 29% decrease in total biomass compared to non-dust conditions. Both herbicides and dust exerted suppressive effects on A. retroflexus's leaf and stem weights and overall biomass. Despite dust presence, tribenuron-methyl (95.8%), aminopyralid + florasulam (95.7%), sulfosulfuron (96.5%), and foramsulfuron + iodosulfuron + thiencarbazone (97.8%) effectively controlled A. retroflexus. These findings indicate that dust's effect on herbicide efficacy is herbicide-dependent but except bentazon, dust generally increased herbicide efficacy and amplified the control of A. retroflexus.

Trp-574-Leu mutation and metabolic resistance by cytochrome P450 gene conferred high resistance to ALS-inhibiting herbicides in Descurainia sophia.

Descurainia sophia (flixweed) is a troublesome weed in winter wheat fields in North China. Resistant D. sophia populations with different acetolactate synthetase (ALS) mutations have been reported in recent years. In addition, metabolic resistance to ALS-inhibiting herbicides has also been identified. In this study, we collected and purified two resistant D. sophia populations (R1 and R2), which were collected from winter wheat fields where tribenuron-methyl provided no control of D. sophia at 30 g a.i. ha-1. Whole plant bioassay and ALS activity assay results showed the R1 and R2 populations had evolved high-level resistance to tribenuron-methyl and florasulam and cross-resistance to imazethapyr and pyrithiobac­sodium. The two ALS genes were cloned from the leaves of R1 and R2 populations, ALS1 (2004 bp) and ALS2 (1998 bp). A mutation of Trp 574 to Leu in ALS1 was present in both R1 and R2. ALS1 and ALS2 were cloned from R1 and R2 populations respectively and transferred into Arabidopsis thaliana. Homozygous T3 transgenic seedlings with ALS1 of R1 or R2 were resistant to ALS-inhibiting herbicides and the resistant levels were the same. Transgenic seedlings with ALS2 from R1 or R2 were susceptible to ALS-inhibiting herbicides. Treatment with cytochrome P450 inhibitor malathion decreased the resistant levels to tribenuron-methyl in R1 and R2. RNA-Seq was used to identify target cytochrome P450 genes possibly involved in resistance to ALS-inhibiting herbicides. There were five up-regulated differentially expressed cytochrome P450 genes: CYP72A15, CYP83B1, CYP81D8, CYP72A13 and CYP71A12. Among of them, CYP72A15 had the highest expression level in R1 and R2 populations. The R1 and R2 populations of D. sophia have evolved resistance to ALS-inhibiting herbicides due to Trp 574 Leu mutation in ALS1 and possibly other mechanisms. The resistant function of CYP72A15 needs further research.

Inhibition of suplatast tosilate on EPSC in the single paratracheal ganglion neurons attached with presynaptic boutons.

Using single neurons of rat paratracheal ganglia (PTG) attached with presynaptic boutons, the effects of suplatast tosilate on excitatory postsynaptic currents (EPSCs) were investigated with nystatin-perforated patch-clamp recording technique. We found that suplatast concentration dependently inhibited the EPSC amplitude and its frequency in single PTG neurons attached with presynaptic boutons. EPSC frequency was higher sensitive to suplatast than EPSC amplitude. IC50 for EPSC frequency was 1.1 × 10-5 M, being similar to that for the effect on histamine release from mast cells and lower than that for the inhibitory effect on cytokine production. Suplatast also inhibited the EPSCs potentiated by bradykinin (BK), but it did not affect the potentiation itself by BK. Thus suplatast inhibited the EPSC of PTG neurons attached with presynaptic boutons at both the presynaptic and postsynaptic sites.NEW & NOTEWORTHY In this study, using single neurons of rat paratracheal ganglia (PTG) attached with presynaptic boutons, the effects of suplatast tosilate on excitatory postsynaptic currents (EPSCs) were investigated with patch-clamp recording technique. We found that suplatast concentration dependently inhibited the EPSC amplitude and its frequency in single PTG neurons attached with presynaptic boutons. Thus suplatast inhibited the function of PTG neurons at both of presynaptic and postsynaptic sites.

Comparative proteomic and physiological analyses reveal tribenuron-methyl phytotoxicity and nontarget-site resistance mechanisms in Brassica napus.

The application of herbicides is the most effective strategy for weed control and the development of herbicide-resistant crops will facilitate the weed management. The acetolactate synthase-inhibiting herbicide, tribenuron-methyl (TBM), is broadly used for weed control. However, its application in rapeseed field is restricted since rapeseed is sensitive to TBM. Herein, an integrated study of cytological, physiological and proteomic analysis of the TBM-resistant rapeseed mutant M342 and its wild-type (WT) plants was conducted. After TBM spraying, M342 showed improved tolerance to TBM, and proteins implicated in non-target-site resistance (NTSR) to herbicides had a significantly higher level in M342 as compared with the WT. Differentially accumulated proteins (DAPs) between these two genotypes were enriched in glutathione metabolism and oxidoreduction coenzyme metabolic process, which protected the mutant from oxidative stress triggered by TBM. Important DAPs related to stress or defence response were up-accumulated in M342 regardless of the TBM treatment, which might serve as the constitutive part of NTSR to TBM. These results provide new clues for further exploration of the NTSR mechanism in plants and establish a theoretical basis for the development of herbicide-resistant crops.

Role of phosphatidylserine in amyloid-beta oligomerization at asymmetric phospholipid bilayers.

Amyloid-beta (Aß1-42) aggregation triggers neurotoxicity and is linked to Alzheimer's disease. Aß1-42 oligomers, rather than extended fibrils, adhere to the cell membrane, causing cell death. Phosphatidylserine (PS), an anionic phospholipid, is prevalent in neuronal membranes (< 20 molar percentage) and, while isolated to the cytoplasmic leaflet of the membrane in healthy cells, its exposure in apoptotic cells and migration to exoplasmic leaflet is triggered by oxidative damage to the membrane. It is widely believed that PS plays a crucial role in the Aß peptide interaction in the membranes of neuronal cells. However, due to the complexity of the cell membrane, it can be challenging to address molecular level understanding of the PS-Aß binding and oligomerization processes. Herein, we use microcavity supported lipid bilayers (MSLBs) to analyse PS and Aß1-42 binding, oligomer formation, and membrane damage. MSLBs are a useful model to evaluate protein-membrane interactions because of their cell-like dual aspect fluidity, their addressability and compositional versatility. We used electrochemical impedance spectroscopy (EIS) and confocal fluorescence microscopy to compare the impact of Aß1-42 on simple zwitterioinic membrane, dioleoylphosphatidylcholine (DOPC), with MSLBs comprised of transversally asymmetric binary DOPC and dioleoylphosphatidylserine (DOPS). Monomeric Aß1-42 adsorbs weakly to the pristine zwitterionic DOPC membrane without aggregation. Using a membrane integrity test, with pyranine trapped within the cavities beneath the membrane, Aß1-42 exposure did not result in pyranine leakage, indicating that DOPC membranes were intact. When 10 mol% DOPS was doped asymmetrically into the membrane's outer leaflet, oligomerization of Aß1-42 monomer was evident in EIS and atomic force microscopy (AFM), and confocal imaging revealed that membrane damage, resulted in extensive pyranine leakage from the pores. The effects were time, and DOPS and Aß1-42 concentration-dependent. Membrane pore formation was visible within 30 minutes, and oligomerization, membrane-oligomer multilayer, and Aß1-42 fibril formation evident over 3 to 18 hours. In asymmetric membranes with DOPS localized to the lower leaflet, optothermally (laser induced) damage increased local DOPS concentrations at the distal leaflet, promoting Aß1-42 aggregation.

The Dual Use of the Pyranine (HPTS) Fluorescent Probe: A Ground-State pH Indicator and an Excited-State Proton Transfer Probe.

Molecular fluorescent probes are an essential experimental tool in many fields, ranging from biology to chemistry and materials science, to study the localization and other environmental properties surrounding the fluorescent probe. Thousands of different molecular fluorescent probes can be grouped into different families according to their photophysical properties. This Account focuses on a unique class of fluorescent probes that distinguishes itself from all other probes. This class is termed photoacids, which are molecules exhibiting a change in their acid-base transition between the ground and excited states, resulting in a large change in their pKa values between these two states, which is thermodynamically described using the Förster cycle. While there are many different photoacids, we focus only on pyranine, which is the most used photoacid, with pKa values of ∼7.4 and ∼0.4 for its ground and excited states, respectively. Such a difference between the pKa values is the basis for the dual use of the pyranine fluorescent probe. Furthermore, the protonated and deprotonated states of pyranine absorb and emit at different wavelengths, making it easy to focus on a specific state. Pyranine has been used for decades as a fluorescent pH indicator for physiological pH values, which is based on its acid-base equilibrium in the ground state. While the unique excited-state proton transfer (ESPT) properties of photoacids have been explored for more than a half-century, it is only recently that photoacids and especially pyranine have been used as fluorescent probes for the local environment of the probe, especially the hydration layer surrounding it and related proton diffusion properties. Such use of photoacids is based on their capability for ESPT from the photoacid to a nearby proton acceptor, which is usually, but not necessarily, water. In this Account, we detail the photophysical properties of pyranine, distinguishing between the processes in the ground state and the ones in the excited state. We further review the different utilization of pyranine for probing different properties of the environment. Our main perspective is on the emerging use of the ESPT process for deciphering the hydration layer around the probe and other parameters related to proton diffusion taking place while the molecule is in the excited state, focusing primarily on bio-related materials. Special attention is given to how to perform the experiments and, most importantly, how to interpret their results. We also briefly discuss the breadth of possibilities in making pyranine derivatives and the use of pyranine for controlling dynamic reactions.

pH Jumps in a Protic Ionic Liquid Proceed by Vehicular Proton Transport.

The dynamics of excess protons in the protic ionic liquid (PIL) ethylammonium formate (EAF) have been investigated from femtoseconds to microseconds using visible pump mid-infrared probe spectroscopy. The pH jump following the visible photoexcitation of a photoacid (8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt, HPTS) results in proton transfer to the formate of the EAF. The proton transfer predominantly (∼70%) occurs over picoseconds through a preformed hydrogen-bonded tight complex between HPTS and EAF. We investigate the longer-range and longer-time-scale proton-transport processes in the PIL by obtaining the ground-state conjugate base (RO-) dynamics from the congested transient-infrared spectra. The spectral kinetics indicate that the protons diffuse only a few solvent shells from the parent photoacid before recombining with RO-. A kinetic isotope effect of nearly unity (kH/kD ≈ 1) suggests vehicular transfer and the transport of excess protons in this PIL. Our findings provide comprehensive insight into the complete photoprotolytic cycle of excess protons in a PIL.

Computer-Aided Design and Synthesis of (Functionalized quinazoline)-(α-substituted coumarin)-arylsulfonate Conjugates against Chikungunya Virus.

Chikungunya virus (CHIKV) has repeatedly spread via the bite of an infected mosquito and affected more than 100 countries. The disease poses threats to public health and the economy in the infected locations. Many efforts have been devoted to identifying compounds that could inhibit CHIKV. Unfortunately, successful clinical candidates have not been found yet. Computations through the simulating recognition process were performed on complexation of the nsP3 protein of CHIKV with the structures of triply conjugated drug lead candidates. The outcomes provided the aid on rational design of functionalized quinazoline-(α-substituted coumarin)-arylsulfonate compounds to inhibit CHIKV in Vero cells. The molecular docking studies showed a void space around the ß carbon atom of coumarin when a substituent was attached at the α position. The formed vacancy offered a good chance for a Michael addition to take place owing to steric and electronic effects. The best conjugate containing a quinazolinone moiety exhibited potency with EC50 = 6.46 µM, low toxicity with CC50 = 59.7 µM, and the selective index (SI) = 9.24. Furthermore, the corresponding 4-anilinoquinazoline derivative improved the anti-CHIKV potency to EC50 = 3.84 µM, CC50 = 72.3 µM, and SI = 18.8. The conjugate with 4-anilinoquinazoline exhibited stronger binding affinity towards the macro domain than that with quinazolinone via hydrophobic and hydrogen bond interactions.

Glyphosate, AMPA, and metsulfuron-methyl retention in the main horizons of a Typic Argiudoll.

Retention is one of the processes controlling the behavior and fate of pesticides in soil. The objective of this work was to evaluate the adsorption and desorption of glyphosate, AMPA, and metsulfuron-methyl in the main horizons of a Typic Argiudoll destined for agricultural use. For this purpose, the batch equilibrium method was used at a range of concentrations for each compound. Desorption was performed in three consecutive steps after the adsorption experiment. The results obtained showed strong adsorption of glyphosate and AMPA in the three horizons, following the trend B > A > C, with weak desorption. Metsulfuron-methyl, on the other hand, showed weak adsorption in the three horizons, following the trend A > B > C, with relevant desorption. Our results allow us to identify metsulfuron-methyl as the compound that poses the greatest environmental risk in terms of the potential contamination of other areas and groundwater. However, despite their strong adsorption and weak desorption, glyphosate and AMPA also represent potential contaminants of other environmental matrices.

The Metabolism of a Novel Cytochrome P450 (CYP77B34) in Tribenuron-Methyl-Resistant Descurainia sophia L. to Herbicides with Different Mode of Actions.

Descurainia sophia L. (flixweeds) is a noxious broad-leaf weed infesting winter wheat fields in China that has evolved high resistance to tribenuron-methyl. In this work, a brand new gene CYP77B34 was cloned from tribenuron-methyl-resistant (TR) D. sophia and transferred into Arabidopsis thaliana, and the sensitivities of Arabidopsis with or without the CYP77B34 transgene to herbicides with a different mode of actions (MoAs) were tested. Compared to Arabidopsis expressing pCAMBIA1302-GFP (empty plasmid), Arabidopsis transferring pCAMBIA1302-CYP77B34 (recombinant plasmid) became resistant to acetolactate synthase (ALS)-inhibiting herbicide tribenuron-methyl, protoporphyrinogen oxidase (PPO)-inhibiting herbicides carfentrazone-ethyl and oxyfluorfen. Cytochrome P450 inhibitor malathion could reverse the resistance to tribenuron-methyl, carfentrazone-ethyl and oxyfluorfen in transgenic Arabidopsis plants. In addition, the metabolic rates of tribenuron-methyl in Arabidopsis expressing CYP77B34 were significantly higher than those in Arabidopsis expressing pCAMBIA1302-GFP. Other than that, the transgenic plants showed some tolerance to very-long-chain fatty acid synthesis (VLCFAs)-inhibiting herbicide pretilachlor and photosystem (PS) II-inhibiting herbicide bromoxynil. Subcellular localization revealed that the CYP77B34 protein was located in the endoplasmic reticulum (ER). These results clearly indicated that CYP77B34 mediated D. sophia resistance to tribenuron-methyl and may have been involved in D. sophia cross-resistance to carfentrazone-ethyl, oxyfluorfen, pretilachlor and bromoxynil.

Tribenuron-methyl-resistant Descurainia sophia L. exhibits negative cross-resistance to imazethapyr conferred by a Pro197Ser mutation in acetolactate synthase and reduced metabolism.

BACKGROUND: Descurainia sophia L. is one of the most notorious weeds infesting winter wheat in China. Mutations at Pro197 in acetolactate synthase (ALS) results in resistance of D. sophia to tribenuron-methyl and cross-resistance to many ALS inhibitors. Negative cross-resistance to imazethapyr was observed in tribenuron-methyl-resistant (TR) D. sophia with the Pro197Ser mutation in a previous study. In the present research, another TR D. sophia with the Pro197Ser mutation was obtained. To explore the mechanisms of negative cross-resistance, the ALS sensitivity, the absorption and metabolism of imazethapyr in tribenuron-methyl-susceptible (TS) and TR D. sophia were studied. RESULTS: The TR D. sophia population with the Pro197Ser mutation (pHB23) displayed negative cross-resistance to imazethapyr and no cross-resistance to imazamox and imazapic. In contrast, TR D. sophia populations with other Pro197 mutations had no or low resistance to imazethapyr. The ALS in the pHB23 population was more susceptible to imazethapyr than that in the TS population. There was no difference in the absorption of imazethapyr, imazamox, and imazapic between TS and pHB23 plants. However, the metabolism of imazethapyr in TS D. sophia was faster than that in pHB23 plants up to 1 week after treatment. There was no significant difference in the metabolism of imazamox and imazapic between TS and pHB23 plants. CONCLUSION: The TR D. sophia population with the Pro197Ser mutation exhibited negative cross-resistance to imazethapyr, which was likely due to reduced metabolism and increased sensitivity of ALS to imazethapyr. © 2021 Society of Chemical Industry.

Evaluation on persistence and mobility of metsulfuron-methyl at oil palm plantation: residue field trial experiment versus VARLEACH model.

The present paper discussed the comparison of the persistence and mobility of metsulfuron-methyl from a residue field trial experiment and simulation using a VARLEACH model. The residue field trial experiment was performed at Sungai Buloh Oil Palm Estate, Selangor. The plots were treated with metsulfuron-methyl at two treatment rates of 15 g a.i ha-1 (T1) and 30 g a.i ha-1 (T2). Soil samples were collected at 0, 1, 3, 7, 14, 21, 30, 60 and 90 days after treatment (DAT) and analysed subsequently by HPLC-UV. The results show that metsulfuron-methyl degraded rapidly in the soil with the half-life (t½) of 6.3 days in T1 and 7.9 days in T2. The simulation of VARLEACH model gave similar pattern of persistence and mobility of metsulfuron-methyl in the soil profile. However, total residues and the mobility of the metsulfuron-methyl were poorly simulated by the VARLEACH model due to consistent overestimation of the quantified residues. Results indicated that the metsulfuron-methyl lost more rapidly than the prediction values from VARLEACH model. In this case, simulation models which use transformation routines similar and which include additional degraded processes such as leaching, volatilisation, plant uptake or runoff could be considered. Albeit, overestimated values on the concentrations of metsulfuron-methyl are reported using VARLEACH model, the model still can be used as rapid and fast approach to predict the behaviour of pesticide at minimum cost.

Assessment of the efficacy of slow-release formulations of the tribenuron-methyl herbicide in field-grown spring wheat.

The efficacy of slow-release formulations of tribenuron-methyl (TBM) embedded in the matrix of degradable poly(3-hydroxybutyrate) blended with birch wood flour [polymer/wood flour/herbicide 50/30/20 wt.%] was compared with the efficacy of TBM as the active ingredient of the Mortira commercial formulation, which was applied as post-emergence spray to treat spring wheat cv. Novosibirskaya 15. The study was conducted in Central Siberia (in the environs of the city of Krasnoyarsk, Russia) from May to August 2020. The biological efficacy of the embedded TBM was 92.3%, which was considerably higher than the biological efficacy of the Mortira formulation used as the post-emergence spray (15.4%). The embedding of TBM into degradable blended matrix enabled long-duration functioning of this unstable herbicide in soil. The sensitivity of weed plants to TBM differed depending on the species. TBM was more effective against A. retroflexus and A. blitoides, which were killed at an earlier stage, than against C. album and G. aparine, whose percentage increased in the earlier stage and which were controlled by the herbicide less effectively and at later stages. On the plot treated with the embedded herbicide, the parameters of the wheat yield structure were the best, and the total yield was the highest: 3360 ± 40 kg/ha versus 3250 ± 50 kg/ha in the group of plants sprayed with the Mortira formulation. The grain produced in all groups was of high quality and was classified as Grade 1 food grain. The highest quality parameters (grain hectoliter mass, gluten, and protein contents) were obtained in the group of plants treated with the embedded herbicide. The study of the embedded TBM confirmed the high efficacy of the experimental formulation.

Proton Transfer from a Photoacid to a Water Wire: First Principles Simulations and Fast Fluorescence Spectroscopy.

Proton transfer reactions are ubiquitous in chemistry, especially in aqueous solutions. We investigate photoinduced proton transfer between the photoacid 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) and water using fast fluorescence spectroscopy and ab initio molecular dynamics simulations. Photoexcitation causes rapid proton release from the HPTS hydroxyl. Previous experiments on HPTS/water described the progress from photoexcitation to proton diffusion using kinetic equations with two time constants. The shortest time constant has been interpreted as protonated and photoexcited HPTS evolving into an "associated" state, where the proton is "shared" between the HPTS hydroxyl and an originally hydrogen bonded water. The longer time constant has been interpreted as indicating evolution to a "solvent separated" state where the shared proton undergoes long distance diffusion. In this work, we refine the previous experimental results using very pure HPTS. We then use excited state ab initio molecular dynamics to elucidate the detailed molecular mechanism of aqueous excited state proton transfer in HPTS. We find that the initial excitation results in rapid rearrangement of water, forming a strong hydrogen bonded network (a "water wire") around HPTS. HPTS then deprotonates in ≤3 ps, resulting in a proton that migrates back and forth along the wire before localizing on a single water molecule. We find a near linear relationship between the emission wavelength and proton-HPTS distance over the simulated time scale, suggesting that the emission wavelength can be used as a ruler for the proton distance. Our simulations reveal that the "associated" state corresponds to a water wire with a mobile proton and that the diffusion of the proton away from this water wire (to a generalized "solvent-separated" state) corresponds to the longest experimental time constant.

Photoacoustic imaging of elevated glutathione in models of lung cancer for companion diagnostic applications.

Companion diagnostics (CDx) are powerful tests that can provide physicians with crucial biomarker information that can improve treatment outcomes by matching therapies to patients. Here, we report a photoacoustic imaging-based CDx (PACDx) for the selective detection of elevated glutathione (GSH) in a lung cancer model. GSH is abundant in most cells, so we adopted a physical organic chemistry approach to precisely tune the reactivity to distinguish between normal and pathological states. To evaluate the efficacy of PACDx in vivo, we designed a blind study where photoacoustic imaging was used to identify mice bearing lung xenografts. We also employed PACDx in orthotopic lung cancer and liver metastasis models to image GSH. In addition, we designed a matching prodrug, PARx, that uses the same SNAr chemistry to release a chemotherapeutic with an integrated PA readout. Studies demonstrate that PARx can inhibit tumour growth without off-target toxicity in a lung cancer xenograft model.

Influence of molecular rebinding on the reaction rate of complex formation.

We simulated Brownian diffusion and reaction-diffusion processes to study the influence of molecular rebinding on the reaction rates of bimolecular reactions. We found that the number of rebinding events, Nreb, is proportional to the target's size and inversely proportional to the diffusion coefficient D and simulation time-step Δt. We found the proportionality constant close to π-1/2. We confirmed that Nreb is defined as a ratio of the activation-limited rate constant ka to the diffusion-limited rate constant, kD. We provide the formula describing the reactivity coefficient κ, modelling the transient-native complex transition for the activation-controlled reaction rates. We show that κ is proportional to (D/Δt)1/2. Finally, we apply our rebinding-including reaction rate model to the real reactions of photoacid dissociation and protein association. Based on literature data for both types of reactions, we found the Δt time-scale. We show that for the photodissociation of a proton, the Δt is equal to 171 ± 18 fs and the average number of rebinding events is approximately equal to 40. For proteins, Δt is of the order of 100 ps with around 20 rebinding events. In both cases the timescale is similar to the timescale of fluctuation of the solvent molecules surrounding the reactants; vibrations and bending in the case of photoacid dissociation and diffusional motion for proteins.

An indicator displacement assay-based optical chemosensor for heparin with a dual-readout and a reversible molecular logic gate operation based on the pyranine/methyl viologen.

We have reported an optical indicator displacement assay (IDA) for heparin with a UV-vis absorbance and fluorescence dual-readout based on pyranine/methyl viologen (MV2+). Upon introducing heparin, pyranine/MV2+ shows a clearly observable increase in UV-vis absorbance and a turn-on of the fluorescence signal. We have demonstrated that the ionic nature of buffers significantly affects the pyranine displacement and the zwitterionic HEPES was most suitable for heparin sensing. After careful screening of experimental conditions, the pyranine/MV2+-based optical chemosensor exhibits a fast, sensitive, and selective response toward heparin. It shows dynamic linear concentration of heparin in the ranges of 0.1-40 U·mL-1 and 0.01-20 U·mL-1 for the absorptive and fluorescent measurements, respectively, which both cover the clinically relevant levels of heparin. As with the animal experiments, the optical chemosensor has been demonstrated to be selective and effective for heparin level qualification in rat plasma. The chemosensor is readily accessible, cost-effective, and reliable, which holds a great promise for potential application on clinical and biological studies. Furthermore, this IDA system can serve as an IMPLICATION logic gate with a reversible and switchable logical manner.

Structural Origin and Vibrational Fingerprints of the Ultrafast Excited State Proton Transfer of the Pyranine-Acetate Complex in Aqueous Solution.

The excited state proton transfer (ESPT) reaction from the photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS or pyranine) to an acetate molecule has been investigated in explicit aqueous solution via excited state ab initio molecular dynamics simulations based on hybrid quantum/molecular mechanics (QM/MM) potentials. In all the trajectories, the direct proton transfer has been observed in the excited state within 1 ps. We find that the initial structural configuration extracted from the ground state distribution strongly affects the ESPT kinetics. Indeed, the relative orientation of the proton donor-acceptor pair and the presence of a water molecule hydrogen bonded to the phenolic acid group of the pyranine are the key factors to facilitate the ESPT. Furthermore, we analyze the vibrational fingerprints of the ESPT reaction, reproducing the blue shift of the acetate CO stretching (COac), from 1666 to 1763 cm-1 testifying the transformation of acetate to acetic acid. Finally, our findings suggest that the acetate CC stretching (CCac) is also sensitive to the progress of the ESPT reaction. The CCac stretching is indeed ruled by the two vibrational modes (928 and 1426 cm-1), that in the excited state are alternately activated when the proton is shared or bound to the donor/acceptor, respectively.

Exogenous addition of silicon alleviates metsulfuron methyl induced stress in wheat seedlings.

Uncontrolled application of herbicides in the agricultural field poses a severe risk to crops by affecting their yields. Therefore, methods are required to reduce the toxic effects of herbicides in plants. Studies indicate that silicon (Si) provides tolerance and enhances defence mechanism of the plant against abiotic stress. But its role in alleviating Metsulfuron methyl (Meth) herbicide induced toxicity in wheat seedlings is still not known. This study highlighted the potential of exogenous addition of Si in the alleviation of toxic effect of Meth herbicide in wheat seedlings. The exposure of wheat seedlings to Meth herbicide reduced the growth, photosynthetic pigments, antioxidant enzyme activity and nitric oxide (NO) content. Further, Meth herbicide also increased cell death and decreased cell viability in root tips. However, addition of Si reversed Meth-induced these alterations. Moreover, Si also activates antioxidant system which helps in scavenging of free radicals generated under Meth herbicide stress in wheat seedlings. Application of Si to Meth treated wheat seedlings also up-regulated silicon transporter gene Lsi1 (silicon influx transporter) and some of the antioxidant enzyme genes. All together, the data indicate that Si has capability of alleviating Meth herbicide stress in wheat seedlings but it appears that endogenous NO has a positive role in this endeavour of Si.

Discovery of pyrazole N-aryl sulfonate: A novel and highly potent cyclooxygenase-2 (COX-2) selective inhibitors.

Based on a new pyrazole sulfonate synthetic method, a novel class of molecules with a basic structure of pyrazole N-aryl sulfonate have been designed and synthesized. The interest in conducting intensive research stems from quite evident anti-inflammatory effects exhibited by the compounds in preliminary animal experiments. A series of compounds were synthesized by different substitutions of the R1, R2, and R3 groups. Within the series, 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and phenyl 5-methyl-3-(4-(trifluoromethyl) phenyl)-1H-pyrazole-1-sulfonate exhibited excellent anti-inflammatory activity (% inhibition of auricular edemas = 27.0 and 35.9, respectively); the in vivo analgesic activity of phenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate was confirmed to be effective (inhibition ratio of writhing = 50.7% and 48.5% separately), and compounds phenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate , 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate were identified as selective COX-2 inhibitors (SI = 455, 10,497 and >189 severally). In Acute Oral Toxicity assays conducted in vivo, the lethal dose 50 (LD50) of 4-iodophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate and 2-chlorophenyl 5-methyl-3-(p-tolyl)-1H-pyrazole-1-sulfonate to mice was >2000 mg/kg BW.