The Glycine soja cytochrome P450 gene GsCYP82C4 confers alkaline tolerance by promoting reactive oxygen species scavenging.

Recent studies have demonstrated the crucial role of Cytochrome P450 enzymes (CYPs) in the production of secondary metabolites, phytohormones and antioxidants in plants. However, their functional characterization specifically under alkaline stress remains elusive. CYP82C4 was the key gene screened from a family of wild soybean CYPs in our previous studies. The aim of this present study was to clone the Glycine soja GsCYP82C4 gene and characterize its functions in Arabidopsis and Glycine max. The results showed that the GsCYP82C4 gene displayed a high expression in different plant tissues at mature stages compared to young stages. Further, higher temporal expression of the GsCYP82C4 gene was noted at 6, 12 and 24 h time points after alkali treatment in leaves compared to roots. In addition, overexpression of GsCYP82C4 improved alkaline stress tolerance in Arabidopsis via increased root lengths and fresh biomass and strengthened the antioxidant defense system via a reduction in superoxide radicals in transgenic lines compared to wild type (WT) and atcyp82c4 mutants. Further, the expression levels of stress-related marker genes were up-regulated in GsCYP82C4 OX lines under alkali stress. The functional analysis of GsCYP82C4 overexpression in soybean displayed better hairy root growth, increased fresh weight, higher antioxidant enzyme activities and reduced lipid peroxidation rates in OX lines compared to the soybean WT (K599) line. In total, our study displayed positive roles of GsCYP82C4 overexpression in both Arabidopsis and Glycine max to alleviate alkaline stress via altering expression abundance of stress responsive genes, stronger roots, higher antioxidant enzyme activities as well as reduced rates of lipid peroxidation and superoxide radicals.

Structural Engineering of Covalent Organic Frameworks Comprising Two Electron Acceptors Improves Photocatalytic Performance.

Covalent organic frameworks (COFs) have recently attracted much attention as potential photocatalysts for hydrogen production. The effective separation of photogenerated charges is a key objective to improve the photocatalytic activity of COFs. Here, four COFs were synthesized through the Schiff-base reaction to investigate whether the presence (simultaneous or not) of triazine and ketone as acceptors in COFs improved electron-hole separation efficiency. Evidence indicated that charge separation was more efficient when triazine and ketone were simultaneously present in the COF. The COF comprising two acceptors displayed the highest photocatalytic hydrogen production rate (31.43 µmol h-1 ; 41.2 and 3.4 times as large as those of the COFs containing only triazine or ketone, respectively). Moreover, the effect of the distance between the two acceptors on the electron-hole separation was investigated by changing the length of a bridging biphenyl ring. It turned out that the transport distance of a single phenyl group was more favorable for the catalytic reaction. This work affords insight and support for the design of efficient COF photocatalysts.

Effect of meteorological factors on the COVID-19 cases: a case study related to three major cities of the Kingdom of Saudi Arabia.

The COVID-19 pandemic affected the world through its ability to cause widespread infection. The Middle East including the Kingdom of Saudi Arabia (KSA) has also been hit by the COVID-19 pandemic like the rest of the world. This study aims to examine the relationships between meteorological factors and COVID-19 case counts in three cities of the KSA. The distribution of the COVID-19 case counts was observed for all three cities followed by cross-correlation analysis which was carried out to estimate the lag effects of meteorological factors on COVID-19 case counts. Moreover, the Poisson model and negative binomial (NB) model with their zero-inflated versions (i.e., ZIP and ZINB) were fitted to estimate city-specific impacts of weather variables on confirmed case counts, and the best model is evaluated by comparative analysis for each city. We found significant associations between meteorological factors and COVID-19 case counts in three cities of KSA. We also perceived that the ZINB model was the best fitted for COVID-19 case counts. In this case study, temperature, humidity, and wind speed were the factors that affected COVID-19 case counts. The results can be used to make policies to overcome this pandemic situation in the future such as deploying more resources through testing and tracking in such areas where we observe significantly higher wind speed or higher humidity. Moreover, the selected models can be used for predicting the probability of COVID-19 incidence across various regions.

Long-Wavelength Ratiometric Fluorescent Probe for the Early Diagnosis of Diabetes.

Diabetes is a metabolic disease caused by high blood sugar. Patients are often suffering from high blood pressure and arteriosclerosis, which may even evolve into liver disease, kidney disease, and other diabetic complications. Dipeptide peptidase IV (DPP-IV) plays an important role in regulating blood sugar levels and is one of the targets for the diagnosis and treatment of diabetes. Here, a long-wavelength ratiometric fluorescent probe DCDHFNH2-dpp4 for detecting DPP-IV was designed and synthesized. DCDHFNH2-dpp4 was used to detect DPP-IV in healthy, tumor-bearing, and diabetic mice, and only diabetic mice showed strong fluorescence signals. In organ imaging, it is found that DPP-IV is relatively enriched in the liver of diabetic mice. In addition, probe DCDHFNH2-dpp4 also exhibited a significant ratiometric fluorescence signal in the serum of diabetic mice. Therefore, the fluorescent probe DCDHFNH2-dpp4 has shown outstanding potential in the early diagnosis of diabetes, and DCDHFNH2-dpp4 is hopeful to be applied to actual clinical medicine.

A ratiometric fluorescent sensor for rapid detection of the pyroglutamate aminopeptidase-1 in mouse tumors.

Pyroglutamate aminopeptidase-1 (PGP-1) is an important enzyme that plays an indispensable role in the process of inflammation. Up to now, few reports have been reported on the detection of PGP-1 activity in vivo and in vitro, and there are no reports on ratiometric detection. Here, the first red-emitting ratiometric fluorescent sensor (DP-1) for the specific detection of PGP-1 both in vivo and in vitro was designed and synthesized by using DCD-NH2 as the luminescent parent and pyroglutamate as a recognition group. After interacting with PGP-1, the amide bond is hydrolyzed by the enzyme and the color of the solution changes from yellow (λabs = 420 nm) to red (λabs = 520 nm), accompanied by obvious fluorescence emission wavelength change (from ∼564 nm to ∼616 nm). The probe has high specificity and sensitivity towards PGP-1 in about 10 min, and the DL is as low as 0.25 ng mL-1. Interestingly, under the stimulation of Freund's incomplete adjuvant and lipopolysaccharide, the imaging of DP-1 in HepG2 and RAW264 cells shows that the expression of PGP-1 is associated with inflammation. What's more, for the first, the imaging of a mouse tumor model confirms that the enzyme is closely related to the occurrence of some inflammation and tumor diseases. These results indicate that DP-1 can be used as an effective tool for real-time monitoring of PGP-1 levels both in vivo and in vitro and the study of inflammatory tumor pathology.

A Thematic Analysis of Multiple Pathways Between Nature Engagement Activities and Well-Being.

Research studies have identified various different mechanisms in the effects of nature engagement on well-being and mental health. However, rarely are multiple pathways examined in the same study and little use has been made of first-hand, experiential accounts through interviews. Therefore, a semi-structured interview was conducted with seven female students who identified the role of nature engagement in their well-being and mental health. After applying thematic analysis, 11 themes were extracted from the data set, which were: "enjoying the different sensory input," "calm nature facilitates a calm mood," "enhancing decision making and forming action plans," "enhancing efficiency and productivity," "alleviating pressure from society's expectations regarding education," "formation of community relations," "nature puts things into perspective," "liking the contrast from the urban environment," "feel freedom," "coping mechanism," and "anxious if prevented or restricted." The results indicate complementary mechanisms for how nature-related activities benefit mental health and well-being that may occupy different levels of experience within a hierarchical framework informed by perceptual control theory.

BODIPY-based asymmetric monosubstituted (turn-on) and symmetric disubstituted (ratiometric) fluorescent probes for selective detection of phosgene in solution and gas phase.

Here, we designed and synthesized two fluorescent probes for detecting phosgene by nucleophilic substitution reaction using BODIPY as a fluorophore and 2-aminobenzylamine as reactive functional group. For the first time, we have studied the similarities and differences between asymmetric monosubstituted (1) and symmetric disubstituted (2) probes. A monosubstituted probe 1 (having a 2-aminobenzylamine group at the 3-position of BODIPY) has fluorescence-enhancing (weak green fluorescence to strong green fluorescence) responce to phosgene in 30 s with a large Stokes shift (∼70 nm) and sensitive property (DL = 0.81 nM); while the disubstituted probe 2 (having two 2-aminobenzylamine groups at the 3, 5-position of BODIPY) has a ratiometric fluorescent responce to phosgene in 2 min. The linear range of the response is wider than that of the monosubstitution probe 1, and the detection limit is also lower (2.36 nM). In addition, probes 1 and 2 can effectively eliminate the interference of other substances with similar chemical structure as phosgene. They can not only detect phosgene in solution environment, but also in gaseous environment quickly and sensitively.

A naphthalimide-based lysosome-targeting fluorescent probe for the selective detection and imaging of endogenous peroxynitrite in living cells.

The morpholine (ML) group can be used as a targeting unit for lysosomes. Here, a novel turn-off fluorescence probe for the highly selective imaging of peroxynitrite (ONOO-) produced by the endogenous stimulation of lysosomes in living cells is presented. The probe, denoted ML-NAP-DPPEA, comprises ML and 2-(diphenylphosphino)ethylamine (DPPE) groups attached to the fluorophore naphthalimide (NAP). ML-NAP-DPPEA shows excellent properties, including high selectivity for ONOO-, low cytotoxicity, and no interference, leading to low detection limits (17.6 nM). In the presence of ONOO-, the secondary amine group (NH) is oxidized to an electron-withdrawing group (HN → O), which quenches the fluorescence of ML-NAP-DPPEA. This intracellular lysosomal imaging technique was tested, and the results pointed to its potential use as a probe for studying the biological function and pathological effects of ONOO- in subcellular structure. Graphical abstract.

Hybrid Metal-Organic-Framework/Inorganic Nanocatalyst toward Highly Efficient Discoloration of Organic Dyes in Aqueous Medium.

Nanoscale metal-organic frameworks (NMOFs) represent a unique class of solids with superior adsorption, mass transport, and catalytic properties. In this study, a facile and novel approach was developed for the generation of hybrid Cu-NMOF/Ce-doped-Mg-Al-LDH nanocatalyst through in situ self-assembly and solvothermal synthesis of a 2D Cu-NMOF, [Cu2(µ-OH)(µ4-btc)(phen)2] n·5 nH2O {H3btc, trimesic acid; phen, 1,10-phenanthroline}, on a cerium-doped Mg-Al layered double hydroxide (Ce-doped-Mg-Al-LDH) matrix. Self-assembly between Cu-NMOF nanocrystals and exfoliated LDH led to their nanoscale mixing and prevented the formation of aggregated Cu-NMOF nanoparticles. In the resulting hybrid nanostructure, Cu-NMOF nanocrystals (∼10-20 nm particle size) are anchored uniformly on a Ce-doped-Mg-Al-LDH's surface, possessing a dimension of several hundred nanometers. Catalytic activity of Cu-NMOF/Ce-doped-Mg-Al-LDH and Cu-NMOF was evaluated under ambient conditions in the reductive degradation (discoloration) of aqueous solutions of 4-nitrophenol (4-NP, model substrate) and a series of commercial organic dyes by applying sodium borohydride as a reducing agent. The Cu-NMOF/Ce-doped-Mg-Al-LDH nanocatalyst exhibited an outstanding catalytic activity toward degradation of 4-NP, with kapp (rate constant) of 0.03 and a catalyst TOF (turnover frequency) up to 7.1 × 103 h-1. Full and very quick discoloration of organic dyes {rhodamine B (RhB), methylene blue (MB), Congo red (CR), methyl orange (MO), and rhodamine 6G (R6G)} was also achieved with TOF values of up to 1.4 × 105/h. A superior activity of the hybrid nanocatalyst over Cu-NMOF can be regarded as a synergic effect among Cu-NMOF and Ce-doped-Mg-Al-LDH components, while the Ce-doped-Mg-Al-LDH carrier acts as a cocatalyst. The hybrid nanocatalyst can easily be recovered and reused successfully for the five consecutive reaction runs with the same catalytic performance. This study also shows that NMOFs can be easily incorporated onto conventional catalyst supports, resulting in hybrid nanocatalysts with a highly uniform structural architecture, controlled chemical composition, and excellent catalytic function.

BODIPY-based fluorescent sensor for imaging of endogenous formaldehyde in living cells.

A new highly selective fluorescent chemosensor for formaldehyde (FA) has been synthesized based on boron dipyrromethene as fluorophore and o-phenylenediamine (OPDA) as reaction group. When FA is added, the fluorescence emission band of the chemosensor red shift (from 525 nm to 548 nm) accompanied by an increase in intensity with strong green fluorescence was observed. This chemosensor also exhibited the lowest detection limit (0.104 µM) distinguished with other articles that have been reported. The application to cellular fluorescence imaging or test papers detection both indicated that the probe was highly responsive to the FA in endogenous cells and in the gaseous environment.

Ciprofloxacin: from infection therapy to molecular imaging.

Diagnosis of deep-seated bacterial infection remains a serious medical challenge. The situation is becoming more severe with the increasing prevalence of bacteria that are resistant to multiple antibiotic classes. Early efforts to develop imaging agents for infection, such as technetium-99m (99mTc) labeled leukocytes, were encouraging, but they failed to differentiate between bacterial infection and sterile inflammation. Other diagnostic techniques, such as ultrasonography, magnetic resonance imaging, and computed tomography, also fail to distinguish between bacterial infection and sterile inflammation. In an attempt to bypass these problems, the potent, broad-spectrum antibiotic ciprofloxacin was labeled with 99mTc to image bacterial infection. Initial results were encouraging, but excitement declined when controversial results were reported. Subsequent radiolabeling of ciprofloxacin with 99mTc using tricarbonyl and nitrido core, fluorine and rhenium couldn't produce robust infection imaging agent and remained in discussion. The issue of developing a robust probe can be approached by reviewing the broad-spectrum activity of ciprofloxacin, labeling strategies, potential for imaging infection, and structure-activity (specificity) relationships. In this review we discuss ways to accelerate efforts to improve the specificity of ciprofloxacin-based imaging.

Significance of 18F-sodium Fluoride Positron Emission Tomography in Characterization of POEMS Osteosclerotic Lesions Better Than 18F-fluorodeoxyglucose Positron Emission Tomography.

Crow-Fukase syndrome (POEMS syndrome) is a rare systemic paraneoplastic syndrome. Bone lesions are manifested by sclerotic osteoblastic lesions often associated with bone pain. Characterization of osseous lesions is always crucial for clinical correlation and better patient management. We present a case where 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT) was unable to characterize a clinically symptomatic patient, and 18F-fluoride PET/CT showed excellent characterization of osteosclerotic lesions. The results were in correlation with already published data and showed that 18F-fluoride PET/CT has better uptake in osteoblastic lesions in POEMS syndrome when compared to 18F-FDG PET/CT and have superior imaging quality in assessing the bone lesions.

Radiosynthesis and Biodistribution of 99mTc-Metronidazole as an Escherichia coli Infection Imaging Radiopharmaceutical.

Bacterial infection poses life-threatening challenge to humanity and stimulates to the researchers for developing better diagnostic and therapeutic agents complying with existing theranostic techniques. Nuclear medicine technique helps to visualize hard-to-diagnose deep-seated bacterial infections using radionuclide-labeled tracer agents. Metronidazole is an antiprotozoal antibiotic that serves as a preeminent anaerobic chemotherapeutic agent. The aim of this study was to develop technetium-99m-labeled metronidazole radiotracer for the detection of deep-seated bacterial infections. Radiosynthesis of 99mTc-metronidazole was carried by reacting reduced technetium-99m and metronidazole at neutral pH for 30 min. The stannous chloride dihydrate was used as the reducing agent. At optimum radiolabeling conditions, ~ 94% radiochemical was obtained. Quality control analysis was carried out with a chromatographic paper and instant thin-layer chromatographic analysis. The biodistribution study of radiochemical was performed using Escherichia coli bacterial infection-induced rat model. The scintigraphic study was performed using E. coli bacterial infection-induced rabbit model. The results showed promising accumulation at the site of infection and its rapid clearance from the body. The tracer showed target-to-non-target ratio 5.57 ± 0.04 at 1 h post-injection. The results showed that 99mTc-MNZ has promising potential to accumulate at E. coli bacterial infection that can be used for E. coli infection imaging.

Fast and Selective Two-Stage Ratiometric Fluorescent Probes for Imaging of Glutathione in Living Cells.

Two fluorescent, m-nitrophenol-substituted difluoroboron dipyrromethene dyes have been designed by nucleophilic substitution reaction of 3,5-dichloro-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY). Nonsymmetric and symmetric probes, that is. BODIPY 1 (with one nitrophenol group at the position 3) and BODIPY 2 (with two nitrophenol groups at the positions 3 and 5) were applied to ratiometric fluorescent glutathione detection. The detection is based on the two-step nucleophilic aromatic substitution of the nitrophenol groups of the probes by glutathione in buffer solution containing CTAB. In the first stage, probe 1 showed ratiometric fluorescent color change from green (λem = 530 nm) to yellow (λem = 561 nm) because of monosubstitution with glutathione (I561nm/I530nm). Addition of excess glutathione caused the second stage of ratiometric fluorescent color change from yellow to reddish orange (λem = 596 nm, I596nm/I561nm) due to disubstitution with glutathione. Therefore, different concentration ranges of glutathione (from less to excess) could be rapidly detected by the two-stage ratiometric fluorescent probe 1 in 5 min. While, probe 2 shows single-stage ratiometric fluorescent detection to GSH (from green to reddish orange, I596nm/I535nm). Probes 1 and 2 exhibit excellent properties with sensitive, specific colorimetric response and ratiometric fluorescent response to glutathione over other sulfur nucleophiles. Application to cellular ratiometric fluorescence imaging indicated that the probes were highly responsive to intracellular glutathione.

A Phenylselenium-Substituted BODIPY Fluorescent Turn-off Probe for Fluorescence Imaging of Hydrogen Sulfide in Living Cells.

Herein a phenylselenium-substituted BODIPY (1) fluorescent turn-off sensor was developed for the purpose to achieve excellent selectivity and sensitivity for H2S detection based on the substitution reaction of the phenylselenide group at the 3-position with H2S. The excess addition of hydrogen sulfide promoted further substitution of the phenylselenide group at the 5-position of the probe and was accompanied by a further decrease in fluorescence emission intensity. Sensor 1 demonstrated remarkable performance with 49-fold red color fluorescence intensity decrease at longer excitation wavelength, a low detection limit (0.0025 µM), and specific fluorescent response toward H2S over anions, biothiols, and other amino acids in neutral media. It showed no obvious cell toxicity and good membrane permeability, which was well exploited for intracellular H2S detection and imaging through fluorescence microscopy imaging.

A fluorescence enhancement probe based on BODIPY for the discrimination of cysteine from homocysteine and glutathione.

Herein, a fluorescent probe BODIPY-based glyoxal hydrazone (BODIPY-GH) (1) for cysteine based on inhibiting of intramolecular charge transfer (ICT) quenching process upon reaction with the unsaturated aldehyde has been synthesized, which exhibits longer excitation wavelength, selective and sensitive colorimetric and fluorimetric response toward cysteine in natural media. The probe shows highly selectivity towards cysteine over homocysteine and glutathione as well as other amino acids with a significant fluorescence enhancement response within 15min In the presence of 50 equiv. of homocysteine, the emission increased slightly within 15min and completed in 2.5h to reach its maximum intensity. Therefore, the discrimination of cysteine from homocysteine and glutathione can be achieved through detection of probe 1. It shows low cytotoxicity and excellent membrane permeability toward living cells, which was successfully applied to detect and image intracellular cysteine effectively by confocal fluorescence imaging.

One-pot synthesis of polyamines improved magnetism and fluorescence Fe3O4-carbon dots hybrid NPs for dual modal imaging.

A one-step hydrothermal method was developed to fabricate Fe3O4-carbon dots (Fe3O4-CDs) magnetic-fluorescent hybrid nanoparticles (NPs). Ferric ammonium citrate (FAC) was used as a cheap and nontoxic iron precursor and as the carbon source. Moreover, triethylenetetramine (TETA) was used to improve the adhesive strength of CDs on Fe3O4 and the fluorescence intensity of CDs. The prepared water-soluble hybrid NPs not only exhibit excellent superparamagnetic properties (Ms = 56.8 emu g(-1)), but also demonstrate excitation-independent photoluminescence for down-conversion and up-conversion at 445 nm. Moreover, the prepared water-soluble Fe3O4-CDs hybrid NPs have a dual modal imaging ability for both magnetic resonance imaging (MRI) and fluorescence imaging.

Fluorescent glutathione probe based on MnO2-phenol formaldehyde resin nanocomposite.

MnO2-phenol formaldehyde resin (MnO2-PFR) nanocomposite is successfully prepared by a simple chemical reduction process. The resultant MnO2-PFR nanocomposite is well characterized. The absorption band of non-fluorescent MnO2 nanosheets overlaps well with the fluorescence emission of PFR nanoparticles. The green fluorescence of PFR in this nanocomposite can be effectively quenched by fluorescence resonance energy transfer from PFR to MnO2. In the presence of glutathione (GSH), the fluorescence of PFR could be recovered due to MnO2 was reduced to Mn(2+) by GSH. The nanocomposite can be use for detecting glutathione in blood serum.

Imidazole derivative-functionalized carbon dots: using as a fluorescent probe for detecting water and imaging of live cells.

A highly sensitive carbon dot-imidazole (CD-imidazole) nanoprobe is prepared through covalently conjugating imidazole group onto the surface of carbon dots for water fluorescence. In organic solvents, quenching of fluorescence occurs via photoinduced electron transfer (PET) process from the imidazole nitrogen to the CD acceptor. Addition of a trace amount of water into CD nanocomposites in various organic solvents leads to a fluorescence turn-on response, which can be attributed to the suppression of PET due to the formation of the "free" ion pair by proton transfer from the carboxyl groups that are on the CDs surface to the imidazole nitrogen through a water-bridge. This phenomenon can be used for the highly selective detection of trace amounts of water in organic solvents. Laser confocal microscope experiment shows the potential utilization of CD-imidazole for the probed proton-transfer reactions in living cells.