Higher Fluorescence Intensity Research Articles

Population profile of haemocytes in the subcastes of the leaf‐cutter ant Atta sexdens (Hymenoptera: Formicidae) unveiled by flow cytometry

AbstractThe leaf‐cutter ant Atta sexdens is crucial in ecological balance and economic activities, due to its contribution to the aeration and accumulation of organic matter in the soil, but it may also be an agricultural pest when it defoliates plants for the fungus growth used as a food source. This leaf‐cutter ant exhibits a polymorphic worker caste system with distinct activities in the colony. These functions are performed by workers classified into subcastes, including gardeners, which are responsible for the fungus and brood care; cleaners (waste removers), which remove wastes; foragers, which collect and transport plant parts to the nest; and soldiers, which are responsible for colony defence and the support of foraging activities. In our previous work, we showed that A. sexdens has five types of circulating haemocytes in the haemolymph, which play a vital role in immune defence. Herein, we further investigated the population profile of circulating haemocytes in the haemolymph of different worker subcastes of A. sexdens using flow cytometry. Each subcaste exhibited a single population of haemocytes in the haemolymph. However, a detailed 3D dispersion analysis uncovered five distinct haemocyte subpopulations, two of which presented higher quantities. The soldier displayed haemocytes with high fluorescence intensity, compared with the gardener, waste remover, and forager, along with increased complexity, compared with the gardener subcaste. These results suggest that these cells may be granulocytes and plasmatocytes, which are known for their role in insect immune defence.

Skin Care Function of Lactoferrin Was Characterized Using Recombinant Human Epidermal Model

The effect of lactoferrin on skin was simulated using a recombinant human epidermal model. The anti-inflammatory and soothing effect of lactoferrin was verified using IL-1α and TSLP Elisa assay. The effects of lactoferrin on the expression of related genes and proteins were detected using qPCR and immunofluorescence staining. The results showed that lactoferrin can effectively enhance the Transepidermal Electrical Resistance (TEER) and inhibit the secretion of inflammatory cytokine IL-1α and TSLP. In addition, it was confirmed using qPCR that lactoferrin had high expression levels on AQP3, FLG, IVL, CLDN1 and HAS1 genes. Immunofluorescence staining confirmed that lactoferrin had high fluorescence intensity and expression in AQP3, Filaggrin and Involucrin. The results showed that lactoferrin improved the skin barrier at higher than 1.5 mg/mL. At the same time, it can have anti-inflammatory and moisturizing effects. This study provides a strong basis for the application of lactoferrin in cosmetics and daily chemical products.

Co-production of fermentable sugars and highly active lignin from eucalyptus via a mild preprocessing with diethylene glycol and chromic chloride

Eucalyptus was pretreated with diethylene glycol catalyzed by 0.02 mol/L CrCl3 for 10 min, resulting in 91 % delignification and 98 % cellulose recovery, with trace fermentation inhibitors generated. After the mild pretreatment, the accessibility and affinity of cellulase to eucalyptus was enhanced, especially since enzyme adsorption rate increased by 1.6-fold. Therefore, glucose yield of pretreated eucalyptus was 7.9-fold higher than that of untreated eucalyptus after hydrolyzed 48 h, in which the maximum glucose concentration reached 62 g/L from eucalyptus by adding Tween 80. According to the characterization analysis, the structure of the eucalyptus lignin-carbohydrate complexes structure was destroyed during the pretreatment, while lignin fragments was likely reacted with diethylene glycol to form the stabilized aromatic ethers. Moreover, the extracted Deg-lignin exhibited better performances than commercial alkali lignin such as higher fluorescence intensity, less negative surface charge, and lower particle size. The mild pretreatment method with diethylene glycol and CrCl3 provided a promising approach for co-production of fermentable sugars and high activity lignin from lignocellulosic biomass.

Fluorescent BF2 Complexes Inspired by Ageladine A

AbstractThe pH‐dependent UV/Vis absorption and fluorescence of several analogs of the marine natural product ageladine A were investigated. Besides ageladine A itself, its BF2 complex and the corresponding debrominated analogs were included, as were the chloro analog of the debromoageladine‐BF2 complex, an imidazolone analog, and a triazole derivative, which lack the free amino group. Importantly, the pH‐dependence of the fluorescence of the chloro analog closely resembles that of the natural product ageladine A, but with about 25‐fold higher fluorescence intensity and a maximum between pH 3 and 6. The imidazolone derivative behaves in a complementary manner and shows fluorescence only above pH 6, but with less intensity than ageladine A. The calculated Stokes shifts agree well with the experiment, which underlines the accuracy of the DFT calculation method (ωB97XD/TApr‐cc‐pVDZ, PCM). The conformational fixation of arylated imidazo[4,5‐c]pyridines by BF2 units seems to be promising with regard to the development of novel, pH‐dependent fluorescent probes.

A Strategy for Rapid Synthesis of Carbon Nanodots with Reversible Photoluminescence Switching for Sensitive Dynamic Anti‐Counterfeiting

AbstractCarbon nanodots (CDs) possess exceptional fluorescence properties, which have been extensively studied in the fields of fluorescence detection and anti‐counterfeiting information. However, the exploration of CDs with simple and fast synthesis paths, secure, and efficient encryption properties, remains a challenge. The rapid synthesis of orange CDs (O‐CDs) is reported with a high photoluminescence quantum yield (PLQY) of 57.6% within 10 min at atmospheric pressure using a one‐step pyrolysis method. The O‐CDs exhibit a dual‐emission property, with a blue emission peak at 425 nm and a strong orange emission peak at 590 nm. The dual‐emission peaks of O‐CDs can allow for fast orange/blue switching of fluorescence color with changes in the acid‐base environment. O‐CDs can serve as effective fluorescent probes for pH detection, depending on their fluorescence wavelength and intensity. Additionally, O‐CDs have potential for fluorescence anti‐counterfeiting. When exposed to NH3 gas, O‐CDs fluorescent ink rapidly (1 s) transitions from orange fluorescence to blue fluorescence, and then quickly (4 s) reverts back to orange fluorescence when the gas environment changes to HCl gas atmosphere. Thus, O‐CDs fluorescent inks offer several advantages, including high fluorescence intensity, fast response, recyclability, and lossless encryption/decryption in “on‐off‐on” double encryption anti‐counterfeiting.

A time-saving pH-ultrasonic-shifting method for insoluble pea protein isolate to encapsulate polyphenol: Binding mechanism, structure, and functional characteristics

The application of the commercial pea protein isolate (CPPI) and polyphenols are often limited by their poor solubility. To address it, a time-saving pH-ultrasonic-shifting method was skillfully developed by combining the pH-shifting and ultrasonic methods to efficiently encapsulate polyphenols, and this final obtained nanoparticles was named CPPI-NAR-4. CPPI-NAR-4 has shown higher encapsulation efficiency (EE, 93.81 ± 0.56%) and loading capacity (LC, 8.58 ± 0.05%) for NAR, smaller particle size (126.40 ± 3.84 nm) and lower zeta potential (−18.50 ± 0.98 mV) as compared to nanoparticles prepared by other three known methods. This high EE and LC of CPPI-NAR-4 were attributed by both CPPI-NAR-4 and CPPI-4 having the higher surface hydrophobicity, the higher fluorescence intensity, and more protein expansion in their comparison. Multi-spectra evaluations indicated that the pH-ultrasonic-shifting process might produce more hydrogen bonding in the combination of CPPI and NAR. As to the interaction mechanisms between CPPI and NAR in CPPI-NAR nanoparticles, molecular docking results showed that hydrogen bonds, van der Waals forces, and hydrophobic interactions were dominant in the binding of NAR and CPPI; further molecular dynamics simulations revealed that NAR and CPPI had more interactions at pH 12 than at pH 7. Based on these experimental and simulative results, it could be suggested that the effects of ultrasonic on the binding between CPPI and NAR might be better at pH 12 than at pH 7. In conclusion, this pH-ultrasonic-shifting method was expected to be further developed for industrial fabricating protein-polyphenol nanoparticles such as CPPI-NAR.

Development of a TaqMan polymerase chain reaction detection method for the precise identification and quantification of an attenuated Eimeria maxima vaccine strain in poultry.

Avian coccidiosis, a parasitic disease prevalent in poultry, is caused by Eimeria species and leads to significant economic losses. The use of attenuated live oocyst vaccines has been adopted as an alternative to the use of anticoccidial drugs. However, the accurate detection and differentiation of vaccine strains from virulent ones remain challenging. Therefore, this study presents a novel TaqMan polymerase chain reaction (PCR) detection method that offers enhanced sensitivity, specificity, and reproducibility compared with traditional PCR techniques. Through whole-genome resequencing and bioinformatics analysis, we identified a molecular marker gene, Em_marker6, with a unique 21-base pair deletion specific to the Eimeria maxima attenuated vaccine strain. Optimized primers and probes targeting this marker enabled rapid quantification cycle value achievement and high fluorescence intensity. The standard curve's slope of -3.540 and correlation coefficient of 0.9971 confirmed precise quantification capabilities. The TaqMan PCR method detected as few as 30 plasmid DNA copies and 50 oocysts per reaction, outperforming traditional PCR techniques by an order of magnitude. No cross-reactivity was observed with other E. maxima wide-type strains or common intestinal pathogens, ensuring the exclusive detection of the E. maxima EMPY vaccine strain. Weekly testing over 3 weeks demonstrated minimal variability, indicating robust consistency in the method's application. Testing on 61 clinical samples revealed a 57.38% positivity rate for E. maxima species and 13.11% for the vaccine strain. The Em_marker6 gene exhibited genetic stability across multiple generations, confirming the detection method's robust stability for the attenuated E. maxima vaccine strain. This study significantly advances the field of avian coccidiosis research and control by providing a valuable tool for monitoring vaccine purity and preventing inadvertent infections in vaccinated flocks, aligning with global efforts to curb antibiotic use in animal feed.

Mechano-responsive and acid stimuli-responsive luminescence of a hydrogen-bonded organic frameworks

Stimuli-responsive materials are capable of changing their chemical or physical properties when exposed to external stimuli, showing a wide range of potential applications such as drug delivery, sensing, smart coatings, and artificial muscles. Here, a micron-sized hydrogen-bonded organic framework PFC-1 was constructed and its mechanical and acid stimuli-responsive luminescence were investigated. It was found that the fluorescence of PFC-1 aqueous suspension is affected HCl concentrations. The pristine PFC-1 aqueous suspension exhibits an emission peak with high fluorescence intensity at 440 nm and two weak emission shoulders at 475 nm and 535 nm, respectively. Upon the addition of hydrochloric acid, there is a gradual reduction in the peak intensities at 440 nm and 475 nm, while the peak intensity at 535 nm remains relatively unchanged, resulting in a progressive shift in fluorescence color from blue to green. Mechanical grinding induces approximate 30 nm blue-shift in the fluorescence emission peak, a change that is reversible upon immersing the powder in ethanol for 60 min. This work contributes to the development of stimuli-responsive hydrogen-bonded organic framework materials with potential applications in acid and pressure fluorescence sensing.

Imaging polarity changes in pneumonia and lung cancer using a lipid droplet-targeted near-infrared fluorescent probe

As the main organ of gas exchange, the lungs are susceptible to various exogenous attacks, and pneumonia is one of the major inflammatory diseases that threaten human health. Generally, pneumonia is a disease that occurs in the alveoli and respiratory bronchioles induced by pathogens and further causes local and systemic inflammatory responses. The development of pneumonia can bring various serious complications, including lung abscess, sepsis, meningitis, brain damage and hearing loss. Over the past few decades, the mortality rate of pneumonia patients has remained high. While lung cancer is another lung-related malignant tumors worldwide, with a low 5 year survival rate. Exploring the mechanisms of their occurrence and interaction between pneumonia and lung cancer is a challenging and meaningful task. The abnormalities of lipid droplets (LDs) polarity have been found strongly accompanied by many diseases, especially cancer, inflammation, and metabolic diseases. However, their exact role is not yet clear. Hence, it is significant to develop a novel detection method to observe the polarity changes of LDs, which would help to reveal the development process of diseases pneumonia and lung cancer. In this work, a new polarity-sensitive LDs-targeted near-infrared probe BFZ up to 712 nm was designed, according to the intramolecular charge transfer mechanism, which displayed high fluorescence intensity in low polarity while showing decreased fluorescence intensity in high-polarity conditions with a significant redshift. The BFZ was successfully applied to the change of LDs polarity in lipopolysaccharide (LPS)-stimulated A549 cells, and a mouse model of lung inflammation. It also tells the polarity differences between normal and tumor cells and between normal and tumor tissues. Moreover, the correlations between pneumonia and polarity changes were observed through the imaging experiments, which may provide an insightful method for the early diagnosis of pneumonia and lung cancer.

Development of a FRET aptasensor based on MoS2-doped Zn-MOF as luminophore for selective detection of cadmium in aqueous solutions.

A robust "on-off" fluorescent aptasensor was developed using nanohybrids of molybdenum sulfide (MoS2) quantum dot (QD)-doped zinc metal-organic frameworks (Zn-MOF) for selective and sensitive detection of cadmium ions (Cd2+) in water. This nanohybrid (MoS2@Zn-MOF), synthesized via "bottle around the ship" methodology, exhibited a high-intensity fluorescence emission centered at 430nm (λEm) (blue) on excitation at 320nm (λEx). Further, the conjugation of this fluorophore to phosphate-modified cadmium aptamer (Cd-2-2) was achieved through carbodiimide reaction. The hybridization of prepared sensing probe (MoS2@Zn-MOF/Cd-2-2 aptamer) was done with dabcyl-conjugated complementary DNA (cDNA), acting as energy donor-acceptor pair in the fluorescence resonance energy transfer (FRET) system. This hybridizationcauses the fluorescence quenching of the nanohybrid. In the presence of Cd2+, the aptamer from the fabricated nano-biosensing probe binds to these ions, resulting in release of dabcyl-cDNA oligomer. This release of dabcyl-cDNA oligomer from the sensing probes restores the fluorescence of the nanohybrid. Under optimized conditions (sensing probe/dabcyl-cDNA ratio 1/7, pH 7.4, and temp 28°C), the sensing probe showed a fast response time of 1min. The fluorescence intensity of the nanohybrid can be utilizedto determine the concentration of Cd2+. The proposed aptasensor achieved highly sensitive detection of Cd2+ with a limit of detection (LOD) of 0.24ppb over the range of 1 × 10-9 to 1 × 10-4M along with minimal effects of interferences (e.g., Hg2+, Pb2+, and Zn2+) and good reproducibility. The designed aptasensor based on MoS2@Zn-MOF nanofluorophore offers a highly sensitive and selective approach for rapid screening of metal ions in aqueous environments.

A low-molecular-weight, long-wavelength emissive Coumarin: Green synthesis, spectral properties, fluorescence enhancement and solvatochromism application

In this study, a novel low-molecular-weight coumarin fluorescent dye, 3,4-dicyano-7-diethylaminocoumarin, was designed. This dye features a donor-π-bridge-acceptor (D-π-A) conjugated structure, which confers superior fluorescence properties.The dye was synthesized using a simple, efficient, and environmentally friendly two-step process, facilitating the direct conversion of the key intermediate into the final product via simultaneous addition and elimination reactions. A comprehensive structural characterization of the dye was undertaken, and its UV absorption and fluorescence emission properties were extensively analyzed using spectroscopic techniques, with structural explanations of the fluorescence activities provided by the Density Functional Theory (DFT) method.Experimental results revealed that this coumarin dye emits strong fluorescence, characterized by a long wavelength, a large Stokes shift, and high fluorescence intensity. It exhibits excellent fluorescent performance in various solvents. Despite experiencing fluorescence quenching in its solid state, the formation of an inclusion complex with β-cyclodextrin restores strong red fluorescence, presenting new possibilities for biofluorescence imaging. Notably, this coumarin dye also demonstrates a significant solvatochromic effect. This effect enables rapid visual discrimination among multiple sets of structurally and chemically similar organic solvents. Consequently, the dye holds promise as a versatile solvatochromic fluorescent probe for a broad spectrum of applications.

Synthesis, characterization and biological activities of nitrophenol-substituted phosphazene dendrimers

This study introduces the synthesis and characterization of two novel nitrophenol-substituted phosphazene dendrimers, [N3P3(OC6H5NO2)6] (III) and [N3P3(OC6H5(NO2)2)5O]ˉ.C6H16N+.H2O (IV), derived from hexachlorocyclotriphosphazene (HCCP). The structures of the compounds were determined using elemental analysis, infrared spectroscopy, and X-ray crystallography. The optical properties of the crystals were investigated by photophysical methods. The thermal properties of the compounds were measured by thermogravimetry-differential thermal analysis (TG-DTA). The antibacterial and anticancer properties of the compounds were tested based on the antibacterial tests against Gram-negative (Escherichia coli ATCC 8739 G(-)) and Gram-positive (Staphylococcus aureus ATCC 6538 G(+), Bacillus subtilis 2a ATCC 23,857 G(+)) bacteria, as well as the MTT assay test on K562 leukemia cells (ATCC: CCL-243) and MCF-7 breast cancer cells (ATCC: HTB-22). The presence of six homogeneous 2-nitrophenol substitutions in compound III reduces the fluorescence of the phosphazene ring. The results showed that compound IV has a higher fluorescence intensity and similar toxicity to MCF-7 and HDF cells. The structural differences and the number of nitro groups in the nitrophenol ligands account for these variations. Our results suggest that these cyclophosphazene derivatives have promising properties for biomedical applications and further studies are warranted to explore their mechanisms of action and therapeutic potential.

Solvent Effects on the Absorption and Emission Spectra of the [5-amino-1-bromoindolizin-3-yl](4-bromophenyl)methanone Molecule.

The effects of solvent on the absorption and emission spectra and dipole moments of the 5ABBM have been extensively studied in a series of solvents. The dipole moments in the excited state are observed to be greater than those in the ground-state in all the solvents studied for the chosen molecule. The dipole moment increase in the excited singlet state ranges from 2.42 to 24.14 D. The experimentally calculated ground state and excited state dipole moments were determined using the solvatochromatic shifts in the absorption and emission spectra as a function of dielectric constant (ɛ) and refractive index (n). These data are used to estimate the excited-state dipole moment using the experimentally determined ground-state dipole moment. A series of fifteen different organic solvents (toluene, methanol, n-butyl alcohol, ethyl acetate, DMS, acetonitrile, benzene, isopropyl alcohol, water, DMF, DCM, DIO, THF, ethanol, and octanol) were investigated at constant dye concentrations. Small changes in the fluorescence spectrum were observed for the different solvents; the highest fluorescence intensity was observed for DMS, and the lowest was observed for water. The Stokes shift in different solvents was studied for the 5ABBM molecule. This results in molecule being more polar in the excited state than in the ground state for the solvents used. The ground state dipole moments, HOMO-LUMO, and molecular electrostatic potential maps were also computed via ab initio calculations and evaluated via Gaussian 09W software.

Fluorescence-guided surgery using cetuximab-800CW in patients with penile carcinoma.

To investigate the feasibility of fluorescence molecular imaging (FMI), using cetuximab-800CW, as an intraoperative tool to determine surgical margins in penile squamous cell carcinoma (PSCC). A total of 11 patients with PSCC received 75 mg cetuximab followed by 15 mg cetuximab-800CW 2 days before surgery. FMI of the whole excision specimen and tissue slices was performed. Fluorescence visualisation was correlated to histopathology. Based on tumour and healthy tissue regions of interest, mean fluorescence intensity was calculated for each individual patient. Significant differences between tumour and healthy mean fluorescence intensity were found with tumour-to-background ratios of a median (IQR) of 1.51 (0.99) and a mean (SD) of 1.51 (0.32) in the excision specimen and tissue slices, respectively. One patient showed a high relative fluorescence intensity with a signal-to-background ratio of 1.79, corresponding to a tumour-positive margin on fresh frozen sectioning. In this Phase I study we showed that cetuximab-800CW seems suitable to discriminate PSCC from background tissue. The tracer was well tolerated, and no false positive spots were seen.

Effects of a Larger N‐Heterocyclic Ring in Rofecoxib Analogues on AIE Activity and Multifunctional Applications

AbstractTwo analogues of rofecoxib, 2‐Pyr‐ROF and 2‐Pip‐ROF, were designed according to the strategy of heterocyclic ring enlargement and facilely synthesized in a facile manner by Knoevenagel reactions. The first compound, 2‐Pyr‐ROF, had low quantum yields (QY) of 3.0 % in the solid states. After replacing the pyrrolidinyl with piperidinyl, the resulting 2‐Pip‐ROF had a significantly increased QY, with a value of 28 %. The root‐mean‐square deviation (RMSD) values between S0 and S1 of 2‐Pyr‐ROF and 2‐Pip‐ROF in tetrahydrofuran were 0.51, 0.35 Å, respectively. As compared with 2‐Pyr‐ROF, compound 2‐Pip‐ROF exhibited a smaller RMSD, which indicated a lower non‐radiative transition rate. A single‐crystal X‐ray diffraction study and Hirshfeld surfaces analysis revealed that 2‐Pip‐ROF had a more nonplanar molecule structure and a weaker π‐π interaction, which might result in a higher fluorescence intensity and QY. Owing to its better aggregation‐induced emission (AIE) behavior, compound 2‐Pip‐ROF showed more multi‐functional applications, including mechanochromism, acidochromism, and lipid droplets imaging ability. These results imply that the strategy of heterocyclic ring enlargement provides a new paradigm for the design of new luminogens with AIE properties.

Hemicyanine-Phenothiazine Based Highly Selective Ratiometric Fluorescent Probes for Detecting Hypochlorite Ion in Fruits, Vegetables and Beverages.

Hypochloric acid (HClO) is a reactive oxygen species (ROS) that functions as a bacteriostatic and disinfectant in food production. Excessive levels of ClO-, however, have been linked to various health issues, including cardiovascular diseases (Halliwell and Gutteridge in Oxford University press, USA, 2015), arthritis, and neurodegenerative diseases (Heinzelmann and Bauer in Biol Chem. 391(6):675-693, 2010). Therefore, synthesizing highly selective and sensitive probes for rapidly detecting endogenous ClO- in daily foods is currently a popular research topic (Kalyanaraman et al. in Redox Biol. 15:347-362, 2018;Winterbourn in Nat Chem Biol. 4(5):278-286, 2008; Turrens in J Physiol. 552(2):335-344, 2003). Thus, we have developed two highly selective ratiometric fluorescent probes (Probe1 and Probe2) based on indole-phenothiazine to detect ClO- in common vegetables, fruits and beverages qualitatively and quantitatively. Moreover, Both Probe1 and Probe2 have shown good specificity and stability, with high fluorescence intensity and long duration (Feng et al. in Adv Sci. 5:1800397, 2018; Wei et al. in Angew Chem. 131(14):4595-4599, 2019; Baruah et al. in J Mater Chem B, 2022).

Development of polymeric nanoparticles associated with SPION and curcumin: a versatile magnetic and fluorescent platform for Life Science applications

Magnetic nanoparticles are prominent in biomedical applications due to their adjustable properties through surface functionalization and inherent magnetism. In the present manuscript, multifunctional nanoparticles were synthesized by combining polymer with a fluorophore and magnetic nanoparticles, resulting in a magnetic and fluorescent nanomaterial. A miniemulsion polymerization technique was employed, using the comonomers methyl methacrylate (MMA) and acrylic acid (AA) in the presence of superparamagnetic iron oxide nanoparticles (SPIONs) and natural turmeric extract (curcumin). Physicochemical characterizations revealed efficient encapsulation of SPIONs within the polymer matrices while maintaining superparamagnetic behavior. The nanosystems exhibited ILP values consistent with those commonly used for magnetic hyperthermia applications, ranging from 0.13 – 0.32 nHm2 kg−1. Additionally, a high fluorescence intensity in the blue/green region was observed, alongside no cell toxicity and substantial internalization in human osteosarcoma cells (OSAS2). Given their intrinsic magnetic and fluorescent properties exhibited, the nanosystems can be considered potential candidates for cell tracking and as a platform in nanotheranostics (MRI, magnetic hyperthermia, and photodynamic therapy).

Salt Tolerance Assessment in Triticum Aestivum and Triticum Durum.

Salt stress is a multicomponent phenomenon; it includes many processes that directly or indirectly affect the plant. Attempts have been made to comprehensively consider the processes of salt stress in plants Triticum aestivum (variety Orenburgskaya 22) and Triticum durum (variety Zolotaya). The study used methods of light and fluorescence microscopy, methods of immunofluorodetection, expression of DNA methyltransferase genes, genes of the ion transporter and superoxide dismutase families, as well as biochemical determination of total antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) reagent. According to morphometric indicators, the Orenburgskaya 22 variety showed greater tolerance to the action of 150 mM NaCl than the Zolotaya variety. The level of expression of genes of the HKT ion transporter family in the Orenburgskaya 22 variety is higher than in the Zolotaya variety. It was found that the expression of the DNA methyltransferase gene DRM2.1, which post-translationally methylates cytosine residues, is 22.3 times higher in Zolotaya compared to Orenburg 22 when exposed to salt. The accumulation of toxic ions is accompanied by an increase in reactive oxygen species (ROS) and increased damage to root tissue, especially in the Zolotaya variety. Using fluorescence microscopy using the Carboxy-H2DFF marker in the Orenburgskaya 22 variety at high NaCl concentrations, the highest fluorescence intensity was determined in the cap zone; in the Zolotaya variety-in the zones of the cap and root meristem. Excess ROS is more successfully removed in the Orenburgskaya 22 variety, which has a higher level of antioxidant activity (AOA), as well as the level of expression of the Cu/ZnSOD and MnSOD superoxide dismutase genes. Using programmed cell death (PCD) markers based on the release of cytochrome c from mitochondria into the cytoplasm, DNA breakage and the release of phosphatidylserine from mitochondria, the degree of damage to root cells was assessed in both wheat varieties. It has been proven that wheat cell death occurs through the mitochondrial pathway. It was noted that the salt-sensitive variety Zolotaya had a significant number of necrotic cells. Based on the data obtained, it was concluded that the Orenburgskaya 22 variety exhibits greater resistance to salinity than the Zolotaya variety. These data may be of practical importance for enhancing protective mechanisms under abiotic stress.

A highly sensitive ratiometric fluorescent probe for detecting HSO3−/SO32− and viscosity change based on FRET/TICT mechanism

BackgroundSulfur dioxide (SO2) is a significant gas signaling molecule in organisms, and viscosity is a crucial parameter of the cellular microenvironment. They are both involved in regulating many physiological processes in the human body. However, abnormalities in SO2 and viscosity levels are associated with various diseases, such as cardiovascular disease, lung cancer, respiratory diseases, neurological disorders, diabetes and Alzheimer's disease. Hence, it is essential to explore novel and efficient fluorescent probes for simultaneously monitoring SO2 and viscosity in organisms. ResultsWe selected quinolinium salt with good stability, high fluorescence intensity, good solubility and low cytotoxicity as the fluorophore and developed a highly sensitive ratiometric probe QQD to identify SO2 and viscosity changes based on Förster resonance energy transfer/twisted intramolecular charge transfer (FRET/TICT) mechanism. Excitingly, compared with other probes for SO2 detection, QQD not only identified HSO3−/SO32− with a large Stokes shift (218 nm), low detection limit (1.87 μM), good selectivity, high energy transfer efficiency (92 %) and wide recognition range (1.87–200 μM), but also identified viscosity with a 26-fold fluorescence enhancement and good linearity. Crucially, QQD was applied to detect HSO3−/SO32− and viscosity in actual water and food samples. In addition, QQD had low toxicity and good photostability for imaging HSO3−/SO32− and viscosity in cells. These results confirmed the feasibility and reliability of QQD for HSO3−/SO32− and viscosity imaging and environmental detection. SignificanceWe reported a unique ratiometric probe QQD for detecting HSO3−/SO32− and viscosity based on the quinolinium skeleton. In addition to detecting HSO3−/SO32− and viscosity change in actual water and food samples, QQD could also monitor the variations of HSO3−/SO32− and viscosity in cells, which provided an experimental basis for further exploration of the role of SO2 derivatives and viscosity in biological systems.

Integration of a biocompatible metal-phenolic network and fluorescence microspheres as labels for sensitive and stable detection of carbendazim with a lateral flow immunoassay

High fluorescence intensity microspheres such as aggregation-induced emission fluorescence microspheres (AIEFM) have improved the sensitivity of lateral flow immunoassay (LFIA). The preparation of immune probes in LFIA usually adopts the chemical coupling strategy with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide for antibody coupling, which has the problems of low coupling efficiency, tedious coupling process, and poor repeatability. A biocompatible metal-phenolic network (MPN), which contains large amounts of phenols and galloyl groups, could easily, quickly, and stably couple with antibodies. Herein, we proposed a strategy based on MPN modification on ultrabright AIEFM surface as a novel label for the rapid detection of carbendazim. The limit of detection of AIEFM@MPN-LFIA was 0.019 ng/mL, which was 4.9 times lower than that of AIEFM-LFIA. In spiked samples, the average recoveries of AIEFM@MPN-LFIA ranged from 80% to 118% (coefficient of variation <13.45%). Therefore, AIEFM@MPN was a promising signal label that could improve the detection performance of LFIA.