Concentration Range Research Articles

Detection and adsorption of florfenicol in milk using bifunctional carbon dot-doped molecularly imprinted polymers.

Detection of florfenicol (FF) residues in animal-derived foods, as one of the most widely used antibiotics, is critically important to food safety. The fluorescent molecularly imprinted polymer (MIP) was synthesized by surface-initiated atom transfer radical polymerization technique with poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres, 4-vinylpyridine, ethylene glycol dimethacrylate, and FF as the matrix, functional monomer, crosslinker, and template molecule, respectively. Meanwhile, N-S co-doped carbon dot (CD) was synthesized with triammonium citrate and thiourea as precursors under microwave irradiation at 400W for 2.5min and then integrated into FF-MIP to obtain CD@FF-MIP. For comparison, non-imprinted polymer (NIP) without FF was also prepared. The adsorption capacity of CD@FF-MIP to FF reached 53.1mgg-1, which was higher than that of FF-MIP (34.7mgg-1), whereas the adsorption capacity of NIP was only 17.3mgg-1. The adsorption equilibrium of three materials was reached within 50min. Particularly, CD@FF-MIP exhibited an excellent fluorescence quenching response to FF in the concentration range of 3-50 µmolL-1. As a result, CD@FF-MIP was successfully utilized to extract FF in milk samples, which were analyzed by high-performance liquid chromatography. The standard recoveries were 95.8%-98.2%, and the relative standard deviation was 1.6%-4.2%. The method showed the advantages of simple operation, high sensitivity, excellent selectivity, and low cost, and also demonstrated a great application prospect in food detection.

Cytotoxic and radical activities of metal-organic framework modified with iron oxide: Biological and physico-chemical analyses

Metal-organic framework (MOF) modified with iron oxide, Fe3O4-MOF, is a perspective drug delivery agent, enabling magnetic control and production of active hydroxyl radicals, •OH, via the Fenton reaction. This paper studies cytotoxic and radical activities of Fe-containing nanoparticles (NPs): Fe3O4-MOF and its components – bare Fe3O4 and MOF (MIL-88B). Luminous marine bacteria Photobacteriumphosphoreum were used as a model cellular system to monitor bioeffects of the NPs. Neither the NPs of Fe3O4-MOF nor MOF showed cytotoxic effects in a wide range of concentrations (<10 mg/L); while Fe3O4 was toxic at >3·10−3 mg/L. The NPs of Fe3O4 did not affect the bacterial bioluminescence enzymatic system; their toxic effect was attributed to cellular membrane processes. The integral content of reactive oxygen species (ROS) was determined using a chemiluminescence luminol assay. Bacteria mitigated excess of ROS in water suspensions of Fe3O4-MOF and MOF, maintaining bioluminescence intensity closer to the control; this resulted in low toxicity of these NPs. We estimated the activity of •OH radicals in the NPs samples with physical and chemical methods – spin capture technology (using electron paramagnetic resonance spectroscopy) and methylene blue degradation. Physico-chemical interpretation of cellular responses is provided in terms of iron content, iron ions release and •OH radical production.

Design, Synthesis, and Xanthine Oxidase Inhibitory Activity of 4-(5-Aminosubstituted-4-cyanooxazol-2-yl)benzoic Acids.

Xanthine oxidase is a known therapeutic target for the treatment of hyperuricemia and related diseases. Despite the availability of current drugs such as allopurinol and febuxostat, the search for new compounds to effectively inhibit this enzyme remains relevant. In our study, 75 virtual structures of 4-(5-aminosubstituted-4-cyanooxazol-2-yl)benzoic acids with structural similarity to febuxostat were designed for evaluation of their potency against xanthine oxidase. After molecular docking simulations, eight compounds were selected for synthesis and in vitro testing. The synthesized compounds were found to exhibit in vitro xanthine oxidase inhibitory activity in the nanomolar concentration range. The most effective inhibitors with 4-benzylpiperidin-1-yl or 1,2,3,4-tetrahydroisoquinolin-2-yl substituents at position 5 of the oxazole ring had IC50 values close to that of febuxostat. The kinetic data suggest a mixed-type inhibition when the inhibitor binds preferentially to the free enzyme rather than to the enzyme-substrate complex. Molecular docking and molecular dynamic simulations were carried out to get insight into the key interactions of the inhibitors bound to the xanthine oxidase active site.

Development of LC–MS/MS Method for the Simultaneous Detection of Emerging Contaminants in Aquatic Matrices

Emerging contaminants (ECs) are substances that have no defined environmental quality standards or regulations, and have the potential to pose major adverse impacts on the environment and human health. The detection of contaminants in the natural environment is the key step for establishing precise environmental risk assessment approach for ECs. However, ECs come from different origins with various physicochemical properties, making their detection a complicated process. Moreover, their presence in the aquatic environment at trace concentration range (ng/L-µg/L), requires an accurate detection at low concentration levels. This study aims to develop an efficient analytical method for simultaneous determination of 5 different ECs in aqueous solution based on solid phase extraction technique (SPE) followed by liquid chromatography-mass spectrometry (LC–MS/MS). High recovery rates (72% to 114%) were achieved for all targeted compounds. Ciprofloxacin (CIP), diuron (DIU), terbutryn (TER) and diclofenac (DIC) had a limit of detection (LOD) of 5 µg/L and a limit of quantification (LOQ) of 10 ng/L, while LOD and LOQ for EE2 were 25 µg/L and 50 ng/L, respectively. These results confirm that the optimized method can be applied for extraction and analysis of ECs from different classes in the aquatic environment.

Unraveling Interspecies Differences in the Phase I Hepatic Metabolism of Alternariol and Alternariol Monomethyl Ether: Closing Data Gaps for a Comprehensive Risk Assessment.

The Alternaria mycotoxins alternariol (AOH) and alternariol 9-O-monomethyl ether (AME) are pervasive food contaminants known to exert adverse effects in vitro, yet their toxicokinetics remain inadequately understood. Thus, this study endeavors to elucidate the qualitative and quantitative aspects of the phase I metabolism of AOH and AME. To pursue this goal, reduced nicotinamide adenine dinucleotide phosphate (NADPH)-fortified porcine, rat, and human liver microsomes were incubated for 0-10 min with AOH or AME within a concentration range of 1-100 and 1-50 μM, respectively. The decline in the parent toxin concentration was monitored via liquid chromatography coupled to tandem mass spectrometry, whereas coupling to high-resolution mass spectrometry provided insights into the composition of the arising metabolic mixture. The collected quantitative data allowed us to calculate the hepatic intrinsic clearance rates of AOH and AME, marking a notable contribution to the field. Moreover, we unveiled interspecies differences in the pattern and rate of the phase I metabolism of the investigated mycotoxins. The presented findings lay the groundwork for physiologically based toxicokinetic modeling aimed at estimating local concentrations of these mycotoxins in specific organs, enhancing our understanding of their mode of action and adverse health effects.

A Visible-Light-Driven Self-Powered Nodularin-R Biosensing Platform Controlled by an Integrated Portable Photoelectrochemical Detection Device.

The presence of nodularin-R (NOD-R) in water has gained considerable attention because of its widespread distribution and high toxicity. In this study, an accurate and rapid visible-light-driven self-powered photoelectrochemical (PEC) biosensor was developed by integrating a portable paper-based electrode with a custom-built miniaturized PEC detection device. The newly designed system successfully achieved on-site detection of NOD-R in real water samples based on PEC technology. First, target recognition triggers the initiation of the hybridization chain reaction to generate double-stranded DNA. The thus-formed double-stranded DNA entrapped methylene blue (MB), and the dye molecules were irradiated with visible light for conversion to leuco-MB in the presence of ascorbic acid. The resulting leuco-MB species significantly amplified the PEC signal output of TiO2-MXene, enabling NOD-R detection. Under optimal conditions, the proposed PEC assay strategy demonstrated NOD-R detection within a concentration range from 20 fg mL-1 to 10 ng mL-1 with a detection limit of 19.6 fg mL-1. In addition, a custom-built miniaturized PEC detection device conveniently integrates the detection component with the light source, enabling the real-time collection of results via a wireless module. This innovative self-powered PEC platform provides significant advancements in smooth and intelligent detection compared to traditional PEC detection devices.

PdRuO2/PVP nanomaterial as a highly selective, stable, and applicable potentiometric sensor for the detection of Cr3+

PdRuO2/PVP nanomaterial was synthesized using a straightforward method and characterized using advanced analytical methods such as TEM, XRD, XPS, elemental mapping and SEM. The synthesized PdRuO2/PVP nanomaterial was used as an ionophore in potentiometric sensor electrodes and successfully adapted to Cr3+ ion detection in a large number of aqueous samples. Several experimental parameters of the PdRuO2/PVP sensor such as potentiometric behavior, selectivity, repeatability, response time, pH, titration, and recovery in real samples were investigated. Potentiometric behavioral characteristics were performed in the concentration range 1 × 10−6–1.0 × 10−1 M. The repeated experiments performed six times showed that there was no deviation in the measurements. The limit of detection of the PdRuO2/PVP potentiometric sensor was very low with a value of 8.6 × 10−8 M. The potentiometric measurements showed that the synthesized PdRuO2/PVP ionophore was highly effective in detecting Cr3+ in a wide pH range of 2.0–8.0 and was found to have a shelf life of over 1 year. As a result, the synthesized PdRuO2/PVP electrode material was found to be highly selective, stable, and applicable for Cr3+ detection.Graphical

1-Butanol treatment enhances drought stress tolerance in Arabidopsis thaliana.

Abiotic stress is a major factor affecting crop productivity. Chemical priming is a promising strategy to enhance tolerance to abiotic stress. In this study, we evaluated the use of 1-butanol as an effectual strategy to enhance drought stress tolerance in Arabidopsis thaliana. We first demonstrated that, among isopropanol, methanol, 1-butanol, and 2-butanol, pretreatment with 1-butanol was the most effective for enhancing drought tolerance. We tested the plants with a range of 1-butanol concentrations (0, 10, 20, 30, 40, and 50mM) and further determined that 20mM was the optimal concentration of 1-butanol that enhanced drought tolerance without compromising plant growth. Physiological tests showed that the enhancement of drought tolerance by 1-butanol pretreatment was associated with its stimulation of stomatal closure and improvement of leaf water retention. RNA-sequencing analysis revealed the differentially expressed genes (DEGs) between water- and 1-butanol-pretreated plants. The DEGs included genes involved in oxidative stress response processes. The DEGs identified here partially overlapped with those of ethanol-treated plants. Taken together, the results show that 1-butanol is a novel chemical priming agent that effectively enhances drought stress tolerance in Arabidopsis plants, and provide insights into the molecular mechanisms of alcohol-mediated abiotic stress tolerance.

Bioenergetic characterization of hyperthermophilic archaean Methanocaldococcus sp. FS406-22.

Hyperthermophilic archaean Methanocaldococcus sp. FS406-22 (hereafter FS406) is a hydrogenotrophic methanogen isolated from a deep-sea hydrothermal vent. To better understand the energetic requirements of hydrogen oxidation under extreme conditions, the thermodynamic characterization of FS406 incubations is necessary and notably underexplored. In this work, we quantified the bioenergetics of FS406 incubations at a range of temperatures (65, 76, and 85℃) and hydrogen concentrations (1.1, 1.4, and 2.1mm). The biomass yields (C-mol of biomass per mol of H2 consumed) ranged from 0.02 to 0.19. Growth rates ranged from 0.4 to 1.5h-1. Gibbs energies of incubation based on macrochemical equations of cell growth ranged from kJ/C-mol to kJ/C-mol. Enthalpies of incubation determined from calorimetric measurements ranged from kJ/C-mol to kJ/C-mol. FS406 growth rates were most comparable to hyperthermophilic methanogen Methanocaldococcus jannaschii. Maintenance energy calculations from the thermodynamic parameters of FS406 and previously determined heterotrophic methanogen data revealed that temperature is a primary determinant rather than an electron donor. This work provides new insights into the thermodynamic underpinnings of a hyperthermophilic hydrothermal vent methanogen and helps to better constrain the energetic requirements of life in extreme environments.

Relative abundance and the fate of human rotavirus in wastewater during treatment processes: identification of potential infectious rotavirus in the final effluents and receiving aquatic milieu in Durban area, South Africa

The occurrence and persistence of rotaviruses in raw and treated wastewater and their discharge into rivers represent a significant health risk for humans and animals, worldwide. In this study, samples were collected monthly from each of the four Durban wastewater treatment plants (DWWTPs) and receiving rivers for a period of 3 months. Rotavirus was quantified by real-time quantitative PCR (RT-qPCR), and viability was assessed using integrated cell culture (ICC)-qPCR. Rotavirus was detected consistently in 100% of influent wastewaters (mean concentration range, 4.36–4.46 log10 genome equivalent (GE) copies/L) and final effluent samples of three DWWTPs (range, 3.35–3.61 log10 GE copies/L). Overall, 94% (45/48) of the wastewater analyzed and 95% (20/21) of the associated river water samples were positive for rotavirus (range, 2.04–6.77 log10 GE copies/L). The activated sludge process with 0.10–0.43 log10 reduction values (LRV) only moderately reduced the viral loads. Similarly, one of the DWWTPs that operated the biofilter modality produced 0.20 LRV. Though the additional treatment with chlorine produced higher LRV (range, 0.31–0.53) than the corresponding activated sludge or biofilter process, the difference in viral removals was not significant (p > 0.05). The equivalent treatment efficiencies of the four DWWTPs varied from 19 to 43% decay in the population of rotavirus. Further, infectious rotavirus ranging from 66.67 to 100%, 50 to 100%, and 66.67 to 100% were detected in the post-activated sludge, final effluents, and river water samples, respectively. In conclusion, the findings of infectious rotavirus in both the final effluents and associated rivers represent an infection risk for humans or animals during contact. Thus, close monitoring for rotavirus and risk assessment studies under distinct exposure scenarios may further shed light on the health-related risks associated with water recovery and reuse in urban settings.

A novel biomass carbon dots ratiometric fluorescence probe coupled with molecularly imprinted polymer for selective detection of aflatoxin B1

The accumulation of Aflatoxin B1 (AFB1) in food and crops can pose significant hazards to human health. Consequently, there has been extensive attention paid to the development of a rapid and reliable method for detecting AFB1 in food. In this context, a ratiometric fluorescence probe (DE-MIPs) was prepared using dual-emission fluorescent carbon dots (CDs) coupled with the molecular imprinting technique for visual detection of AFB1. The dual-emission CDs consisted of red fluorescence biomass CDs (R-CDs) wrapped by molecularly imprinted cavities (R-CDs@MIPs), which served as a response signal, and pure blue emission biomass CDs (B-CDs) as a reference signal. Due to the specific quenching effect of AFB1 on red fluorescence while leaving blue fluorescence unaffected, there was a gradual decrease in the fluorescence intensity ratio (I670/I437) and a distinct shift in fluorescence color from red to blue as the concentration of AFB1 increased. The ratiometric probe demonstrated excellent linearity in detecting AFB1 within the concentration range of 0.1–200 ng/mL, with a detection limit (LOD) of 0.05 ng/mL. Furthermore, the practicality of DE-MIPs was validated by successfully detecting AFB1 in vegetable oil, with desirable recoveries from 89.0% to 107.4%. Furthermore, the integration of a smartphone as colorimetric reader enabled rapid AFB1 detection by capturing changes in fluorescence color. Overall, the development of this ratiometric probe offers a novel perspective for the facile and efficient identification of AFB1 in complex food samples.

Silver phosphate-modified carbonate apatite honeycomb scaffolds for anti-infective and pigmentation-free bone tissue engineering

Bone regeneration using synthetic materials has a high rate of surgical site infection, resulting in severe pain for patients and often requiring revision surgery. We propose Ag3PO4-based surface modification and structural control of scaffolds for preventing infections in bone regeneration. We demonstrated the differences in toxicity and antibacterial activity between in vitro and in vivo studies and determined the optimal silver content in terms of overall anti-infection effects, bone regeneration, toxicity, and pigmentation. A honeycomb structure comprising osteoconductive and resorbable carbonate apatite (CAp) was used as the base scaffold. CAp in the scaffold surface was partially replaced with different concentrations of Ag3PO4 via controlled dissolution-precipitation reactions in an AgNO3 solution. Both bone regeneration and infection prevention were achieved at 860–2300 ppm of silver. Despite the absence of Ag3PO4, honeycomb scaffolds were less susceptible to infection, even under conditions where infection occurs in clinically used three-dimensional porous scaffolds. Regardless of in vitro cytotoxicity at >5200 ppm of silver, increasing the silver content to 21,000 ppm did not adversely affect in vivo bone formation and scaffold resorption or cause acute systemic toxicity. Rather, bone formation was enhanced with 5200 ppm of silver. However, pigmentation was observed at that concentration. Hence, we concluded that the optimal silver concentration range is 860–2300 ppm for anti-infective and pigmentation-free bone regeneration. Bone regeneration was achieved via surface modification, resulting in the rapid release of silver ions immediately after implantation, followed by gradual release over several months. The scaffold structure may also aid in preventing bacterial growth within the scaffolds.

Non-Destructive Analysis of Subvisible Particles with Mie-Scattering-Based Light Sheet Technology: System Development

The characteristics of subvisible particles (SbVPs) are critical quality attributes of injectable and ophthalmic solutions in pharmaceutical manufacturing. However, current compendial SbVP testing methods, namely the light obstruction method and the microscopic particle count method, are destructive and wasteful of target samples. In this study, we present the development of a non-destructive SbVP analyzer aiming to analyze SbVPs directly in drug product (DP) containers while keeping the samples intact. Custom sample housings are developed and incorporated into the analyzer to reduce optical aberrations introduced by the curvature of typical pharmaceutical DP sample containers. The analyzer integrates a light-sheet microscope structure and models the side scattering event from a particle with Mie scattering theory with refractive indices as prior information. Equivalent spherical particle size under assigned refractive index values is estimated, and the particle concentration is determined based on the number of scattering events and the volume sampled by the light sheet. The resulting analyzer's capability and performance to non-destructively analyze SbVPs in DP containers were evaluated using a series of polystyrene bead suspensions in ISO 2R and 6R vials. Our results and analysis show the particle analyzer is capable of directly detecting SbVPs from intact DP containers, sorting SbVPs into commonly used size bins (e.g. ≥ 2 µm, ≥ 5 µm, ≥ 10 µm, and ≥ 25 µm), and reliably quantifying SbVPs in the concentration range of 4.6e2 to 5.0e5 particle/mL with a margin of ± 15 % error based on a 90 % confidence interval.

Very high high-density lipoprotein cholesterol may be associated with higher risk of cognitive impairment in older adults

BackgroundPrevious studies have shown that high-density lipoprotein cholesterol (HDL-C) levels are positively associated with cognitive function across a range of concentrations. However, recent studies have suggested that very high HDL-C levels may lead to poorer outcomes. Therefore, we aimed to investigate the relationship between different concentrations of HDL-C and cognitive impairment risk.MethodsWe collected data from 3632 participants aged over 60 years from the U.S. National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014 to assess the relationship between HDL-C and cognitive function. Cognitive function was evaluated with the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) test, the animal fluency test (AFT), and the digit symbol substitution test (DSST). We used restricted cubic spline models and logistic regression to examine the association between HDL-C and cognitive function.ResultsA U-shaped was observed between HDL-C and cognitive outcomes, individuals with higher risk in those with both low and very high HDL-C levels compared with those with midrange values. Very high HDL-C levels (≥ 2.50 mmol/L) were associated with increased risk of cognitive impairment (OR = 2.19; 95% CI, 1.12–4.28) compared with those with HDL-C levels in the range of 1.50 to 1.99 mmol/L in older adults after adjustment for confounding factors. Interaction test demonstrated that relationship between very high HDL-C and the risk of cognitive impairment was not changed in different sex and race group (P for interaction > 0.05).ConclusionsVery high HDL-C levels were associated with an increased risk of cognitive impairment. HDL-C may not be a protective factor for maintaining brain health in older adults at very high levels.

Theoretical generation and manipulation of concentric rings by light waves on scattering from a collection of anisotropic particles

A theoretical method is proposed for generating far-zone scattered fields with concentric ring-like intensity distribution by properly controlling the distribution characteristics of particles. As an example, a collection of anisotropic Gaussian-centered determinate particles with quasi-homogeneous distribution is discussed. The results show that the number and size of concentric rings can be flexibly adjusted by controlling the structural parameters of the collection of particles. In addition, by adjusting the effective length of each particle’s scattering potential in different directions, a conversion of the distribution of the scattered field from the concentric ring to the crescent lobe can be achieved.

A Comparative Study of Phase I and II Hepatic Microsomal Biotransformation of Phenol in Three Species of Salmonidae: Hydroquinone, Catechol, and Phenylglucuronide Formation

The in vitro biotransformation of phenol at 11 °C was studied using pre-spawn adult rainbow (Oncorhynchus mykiss) (RBT), brook (Salvelinus fontinalis) (BKT), and lake trout (Salvelinus namaycush) (LKT) hepatic microsomal preparations. The incubations were optimized for time, cofactor concentration, pH, and microsomal protein concentration. Formation of Phase I ring-hydroxylation and Phase II glucuronidation metabolites was quantified using HPLC with dual-channel electrochemical and UV detection. The biotransformation of phenol over a range of substrate concentrations (1 to 180 mM) was quantified, and the Michaelis–Menten kinetics constants, Km and Vmax, for the formation of hydroquinone (HQ), catechol (CAT), and phenylglucuronide (PG) were calculated. Species differences were noted in the Km values for Phase I enzyme production of HQ and CAT, with the following rank order of apparent enzyme affinity for substrate: RBT &gt; BKT = LKT. However, no apparent differences in the Km for Phase II metabolism of phenol to PG were detected. Conversely, while there were no apparent differences in Vmax between species for HQ or CAT formation, the apparent maximum capacity for PG formation was significantly less in LKT than that observed for RBT and BKT. These experiments provide a means to quantify metabolic activation and deactivation of xenobiotics in fish, to compare activation and deactivation reactions across species, and to act as a guide for future predictions of new chemical biotransformation pathways and rates in fish. These experiments provided the necessary rate and capacity (Km and Vmax) inputs that are required to parameterize a fish physiologically based toxicokinetic (PB-TK) model for a reactive chemical that is readily biotransformed, such as phenol. In the future, an extensive database of these rate and capacity parameters on important fish species for selected chemical structures will be needed to allow the effective use of predictive models for reactive, biotransformation chemicals in aquatic toxicology and environmental risk assessment.

Gas Free Dissipation Characteristics Analysis and Safety Repair Time Determination of Buried Pipeline Leakage Based on CFD

Buried pipelines, as the most common method of natural gas transportation, are prone to pipeline leakage accidents and are difficult to detect due to their harsh and concealed environment. This paper focused on the problem regarding the free dissipation of residual gas in buried gas pipelines and soil after closing the gas supply end valve after a period of leakage by numerical simulation. A multiple non-linear regression model was established based on the least squares method and multiple regression theory, and MATLAB 2016b mathematical calculation software was used to solve the problem. The research results indicated that compared to the gas leakage diffusion stage, the pressure and velocity distribution during the free dissipation stage were significantly reduced. The increase in leakage time, pipeline pressure, leakage size, and pipeline burial depth led to a large accumulation of natural gas, which increased the concentration and distribution range of gas on the same free dissipation stage monitoring line. A prediction model for natural gas concentration in the free dissipation stage was established with an average error of 7.88%. A calculation model for the safety repair time of buried gas pipeline leakage accidents was further derived to determine the safety repair time of leakage accidents.

Grating-Integrated Gold Nanograsses Encapsulated with ZIF-8: A Quantitative and Ultrasensitive Surface-Enhanced Raman Scattering Substrate.

We proposed and demonstrated highly sensitive hybrid surface-enhanced Raman scattering (SERS) substrates, which are grating-integrated gold nanograsses (GIGN) that are tip-selectively encapsulated by ZIF-8 nanospheres (GIGN/tip-ZIF). This unique structure is realized through the tip-selective modification of GIGN by polyvinylpyrrolidone (PVP), and then, the tips of the GIGN were encapsulated by ZIF-8 nanospheres. The ZIF-8 nanospheres can adsorb analyte molecules, resulting in the spatial overlap between the analyte molecules and the "hotspots" on the tips of GIGN. Such a unique GIGN/tip-ZIF hybrid SERS substrate exhibits high sensitivity and quantitative detection ability. The detection limits can reach as low as 10-11 M, and the relative standard deviation is 5.59% for 4-aminothiophenol (4-ATP). In a wide range of concentrations from 10-5 to 10-11 M, the SERS intensity and concentration relationship can be fitted as a sigmoidal curve with R2 = 0.988. These indicate that the GIGN/tip-ZIF hybrid SERS substrates have broad applications in detecting toxic and harmful substances in food safety, disease diagnosis, and environmental monitoring.

First Report of Trichoderma hamatum Causing Postharvest Bulb Rot on Lilium davidii var. willmottiae in China.

Lilium davidii var. willmottiae, known as Lanzhou lily, is a famous edible crop that is mostly distributed in the middle area of Gansu Province in China. In the winter of 2019, symptoms of bulb rot were observed on Lanzhou lilies harvested from Lanzhou, Gansu Province, during storage at the Institute of Grassland, Flowers and Ecology (39°57'55.984" N, 116°20'8.124" E), Beijing Academy of Agriculture and Forestry Sciences, at an incidence of nearly 50%. The decayed bulb (Fig.1a)was washed under tap water and surface disinfested with 75% ethanol for 1 min, followed by 2.5% sodium hypochlorite for 5 min, and washed with sterile distilled water three times. The 5 mm×5 mm tissue pieces from the junction of the diseased part and the healthy part were clipped, placed on potato dextrose agar (PDA) medium and subsequently incubated at 25 °C. Thirteen dominant pure fungal isolates with the same morphological characteristics were obtained by the hyphal-tip method. Three representative isolates LZ-8, LZ-9-2 and LZ-10 were chosen for phylogenetic analyses. The internal transcribed spacer (ITS), translation elongation factor 1-alpha (TEF-1a), and RNA polymerase II second largest subunit (RPB2) sequences were PCR amplified using the primer pairs ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999), and RPB2-5F2/RPB2-7cR (O'Donnell et al. 2022), respectively. BLAST analysis showed that the ITS,TEF-1a, and RPB2 sequences of the isolates LZ-8 (GenBank accession nos. PP422096, PP447248, and PP447251), LZ-9-2 (GenBank accession nos. PP422098, PP447249, and PP447252) and LZ-10 (GenBank accession nos. PP422099, PP447250, and PP447253) had 99.27 to 99.71% identity with multiple GenBank sequences of Trichoderma hamatum, and the three DNA fragments of the three isolates showed 100% sequence identity. A phylogenetic tree based on concatenated sequences of the three genes using maximum -likelihood analyses revealed that the three isolates LZ-8, LZ-9-2 and LZ-10 were in the same clade with T. hamatum strains (Fig.2). One representative isolate, LZ-10, was chosen for morphological studies and test of the pathogenicity. The colony of LZ-10 on PDA appeared white with cotton-shaped aerial hyphae early, which later turned light green to green and formed concentric rings (Fig.1d-1f). At the end of conidiophores, three to six pear-shaped branches were irregularly gathered(Fig.1h). Conidia were ellipsoid with the size of 3.1 to 4.4 × 2.2 to 3.1 µm (n =20) (Fig.1g). These morphological characteristics were consistent with the description of Trichoderma hamatum. (Kamala et al. 2015, Han et al. 2017).To test pathogenicity, healthy bulbs were punctured with disposable sterilized needles and soaked in equal amounts of sterile water and conidial suspension (1×107 conidia/mL) for 30 min respectively. The pathogenicity experiment was repeated three times. After 6 days of inoculation at 25 °C and 80% relative humidity, the surface of the inoculated bulbs produced water-stained spots and mycelium layers(Fig.1b-1c) consistent with the symptoms exhibited by Lilium davidii var. willmottiae bulbs during storage, meanwhile the uninoculated lily bulbs remained symptomless. Trichoderma hamatum was reisolated from the infected bulbs and identified based on morphological and molecular characteristics, fulfilling Koch's postulates. To our knowledge, this is the first report of bulb rot on Lilium davidii var. willmottiae caused by Trichoderma hamatum in China. This study will contribute to a better understanding and controlling of this postharvest disease in Lilium davidii var. willmottiae.

Polar metabolomics using trichloroacetic acid extraction and porous graphitic carbon stationary phase

IntroductionAccurately identifying and quantifying polar metabolites using untargeted metabolomics has proven challenging in comparison to mid to non-polar metabolites. Hydrophilic interaction chromatography and gas chromatography–mass spectrometry are predominantly used to target polar metabolites.ObjectivesThis study aims to demonstrate a simple one-step extraction combined with liquid chromatography–mass spectrometry (LC–MS) that reliably retains polar metabolites.MethodsThe method involves a MilliQ + 10% trichloroacetic acid extraction from 6 healthy individuals serum, combined with porous graphitic carbon liquid chromatography–mass spectrometry (LC–MS). The coefficient of variation (CV) assessed retention reliability of polar metabolites with logP as low as − 9. QreSS (Quantification, Retention, and System Suitability) internal standards determined the method's consistency and recovery efficiency.ResultsThe method demonstrated reliable retention (CV < 0.30) of polar metabolites within a logP range of − 9.1 to 5.6. QreSS internal standards confirmed consistent performance (CV < 0.16) and effective recovery (70–130%) of polar to mid-polar metabolites. Quality control dilution series demonstrated that ~ 80% of annotated metabolites could be accurately quantified (Pearson’s correlation coefficient > 0.80) within their concentration range. Repeatability was demonstrated through clustering of repeated extractions from a single sample.ConclusionThis LC–MS method is better suited to covering the polar segment of the metabolome than current methods, offering a reliable and efficient approach for accurate quantification of polar metabolites in untargeted metabolomics.