Oxidative stress in the alveolar lavage fluid of children with Mycoplasma pneumoniae pneumonia.

OBJECTIVE: To investigate the correlation between oxidative stress in the bronchoalveolar lavage fluid (BALF) of children with Mycoplasma pneumoniae pneumonia (MPP) and the clinical characteristics of severe MPP (SMPP) and refractory MPP (RMPP). METHODS: Clinical and BALF-related data were collected from 83 patients with MPP, of which 29 had SMPP and 54 had general MPP (GMPP); 37 patients were in the RMPP group and 46 in the non-RMPP group. The levels of malondialdehyde (MDA) and advanced oxidation protein products (AOPP) as well as the activity levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) in BALF were detected. Logistic regression analyses were performed on MDA, AOPP, SOD, GSH-PX, gender, heat peak, neutrophil percentage, C-reactive protein, lactate dehydrogenase, d-dimer, lung consolidation, sputum embolus, and pleural effusion. RESULTS: The levels of MDA and AOPP in the BALF of the MPP group were significantly higher than those in the control group (p < .05), whereas SOD and GSH-PX levels were lower than those in the control group (p < .05). The BALF AOPP levels in the RMPP group were higher than those in the non-RMPP group, and the SOD and GSH-PX levels in the BALF were lower than those in the non-RMPP group; the difference was statistically significant (p < .05). The levels of MDA and AOPP in the BALF of children in the SMPP group were higher than those in the GMPP group, and the levels of SOD and GSH-PX were lower than those in the GMPP group, with statistically significant differences (p < .05). The C-index of the logistic regression model was 0.960 (95% confidence interval 0.958-0.963), which indicates that the model has good predictive ability. CONCLUSION: Advanced oxidation protein products may be a marker for predicting the conditions of SMPP and RMPP, and the prediction model can assess the risk of progression in children to RMPP, which is conducive to clinical diagnosis and treatment.

Studying allosteric regulation of chemokines and antagonists using a nanoscale hCCR3 receptor sensor.

CC chemokine receptor-3 (hCCR3), a G protein-coupled receptor (GPCR) expressed predominantly on eosinophils, is an important drug target. However, it was unclear how chemokine ligands, activators and antagonists recognize hCCR3, and quantitative measurements of hCCR3 inhibition or activation were rare. This study constructed a nanogold receptor sensor using hCCR3 as the molecular recognition element and horseradish peroxidase as the signal amplifier. We quantified the kinetic antagonism between chemokines and hCCR3 before and after adding hCCR3 antagonists. A molecular docking study was carried out to investigate how hCCR3 and its ligands work. The study results indicate chemokines interact with hCCR3 at low concentrations, and reversible hCCR3 inhibitors solely inhibit hCCR3, not CCLs. Moreover, a quantitative evaluation of hCCR3 chemokine activators and their antagonists was carried out using a directed weighted network. This offers a novel approach to quantitatively evaluate chemokine-receptor activation and antagonism together. This research could potentially offer new insights into the mechanisms of action of chemokines and drug screening.

Study of the Sensing Kinetics of G Protein-Coupled Estrogen Receptor Sensors for Common Estrogens and Estrogen Analogs.

Endogenous and exogenous estrogens are widely present in food and food packaging, and high levels of natural estrogens and the misuse or illegal use of synthetic estrogens can lead to endocrine disorders and even cancer in humans. Therefore, it is consequently important to accurately evaluate the presence of food-functional ingredients or toxins with estrogen-like effects. In this study, an electrochemical sensor based on G protein-coupled estrogen receptors (GPERs) was fabricated by self-assembly, modified by double-layered gold nanoparticles, and used to measure the sensing kinetics for five GPER ligands. The interconnected allosteric constants (Ka) of the sensor for 17ß-estradiol, resveratrol, G-1, G-15, and bisphenol A were 8.90 × 10-17, 8.35 × 10-16, 8.00 × 10-15, 5.01 × 10-15, and 6.65 × 10-16 mol/L, respectively. The sensitivity of the sensor for the five ligands followed the order of 17ß-estradiol > bisphenol A > resveratrol > G-15 > G-1. The receptor sensor also demonstrated higher sensor sensitivity for natural estrogens than exogenous estrogens. The results of molecular simulation docking showed that the residues Arg, Glu, His, and Asn of GPER mainly formed hydrogen bonds with -OH, C-O-C, or -NH-. In this study, simulating the intracellular receptor signaling cascade with an electrochemical signal amplification system enabled us to directly measure GPER-ligand interactions and explore the kinetics after the self-assembly of GPERs on a biosensor. This study also provides a novel platform for the accurate functional evaluation of food-functional components and toxins.

Timing of bronchoscopy and application of scoring tools in children with severe pneumonia.

BACKGROUND: There is still a lack of effective scoring criteria for assessing the severity of pulmonary infection associated with changes in the endobronchial lining of the bronchus in children. This study aimed to ascertain the timing and value of endoscopic scoring of fibreoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) in children with severe pneumonia. METHOD: The clinical data of 229 children with severe pneumonia treated with BAL in the Pediatric Intensive Care Unit of the First Affiliated Hospital of Xinxiang Medical University between November 2018 and December 2021 were collected. According to the severity of the disease, patients were divided into an invasive ventilation group and a non-invasive ventilation group, as well as an early BAL group (receiving BAL within 1 day of admission) and a late BAL group (receiving BAL 2 days after admission). A Student's t-test, Chi-square test, receiver operating characteristic (ROC) curve and survival curve were used to analyse the bronchitis score, aetiology of BAL fluid and survival data. RESULTS: The scores of endoscopic mucosal oedema, erythema and pallor and the total score in the invasive ventilation group were higher than those in the non-invasive ventilation group (P < 0.05), and they were consistent with the Sequential Organ Failure Assessment (SOFA) scores. The secretion colour score was lower in the early BAL group than in the late BAL group (P < 0.05). On the bronchitis scores, which were evaluated using a ROC curve, the difference in the mucosal erythema, pallor, oedema and total score of the invasive and non-invasive groups was statistically significant (P < 0.05), which was consistent with the area under the ROC of the SOFA scores. Acute Physiology and Chronic Health Assessment II and SOFA scores after FOB were lower than those before treatment (P < 0.05). In terms of ICU hospitalisation days and total hospitalisation days, the time of the early FOB patients was shorter than that of the late FOB patients (P < 0.05). A total of 22 patients (9.61%) died. The Kaplan-Meier analysis and log-rank test showed that the survival rate of the non-invasive ventilation group was higher than that of the invasive ventilation group (P < 0.05). CONCLUSION: This study found that FOB combined with BAL is an important method for the diagnosis and treatment of severe pneumonia. Early BAL can reduce hospitalisation and ICU time; however, it cannot improve the survival rate. The endoscopic score has a certain role to play in assessing the severity of pulmonary inflammation, but studies with a large sample are still needed to confirm this.

Comparative Study on the Sensing Kinetics of Carbon and Nitrogen Nutrients in Cancer Tissues and Normal Tissues Based Electrochemical Biosensors.

In this study, an electrochemical sensor was developed by immobilizing colon cancer and the adjacent tissues (peripheral healthy tissues on both sides of the tumor) and was used to investigate the receptor sensing kinetics of glucose, sodium glutamate, disodium inosinate, and sodium lactate. The results showed that the electrical signal triggered by the ligand-receptor interaction presented hyperbolic kinetic characteristics similar to the interaction of an enzyme with its substrate. The results indicated that the activation constant values of the colon cancer tissue and adjacent tissues differed by two orders of magnitude for glucose and sodium glutamate and around one order of magnitude for disodium inosinate. The cancer tissues did not sense sodium lactate, whereas the adjacent tissues could sense sodium lactate. Compared with normal cells, cancer cells have significantly improved nutritional sensing ability, and the improvement of cancer cells' sensing ability mainly depends on the cascade amplification of intracellular signals. However, unlike tumor-adjacent tissues, colon cancer cells lose the ability to sense lactate. This provides key evidence for the Warburg effect of cancer cells. The methods and results in this study are expected to provide a new way for cancer research, treatment, the screening of anticancer drugs, and clinical diagnoses.

Kinetics of Drug Molecule Interactions with a Newly Developed Nano-Gold-Modified Spike Protein Electrochemical Receptor Sensor.

In March 2020, the World Health Organization (WHO) declared COVID-19 a pandemic, and the spike protein has been reported to be an important drug target for anti-COVID-19 treatment. As such, in this study, we successfully developed a novel electrochemical receptor biosensor by immobilizing the SARS-CoV-2 spike protein and using AuNPs-HRP as an electrochemical signal amplification system. Moreover, the time-current method was used to quantify seven antiviral drug compounds, such as arbidol and chloroquine diphosphate. The results show that the spike protein and the drugs are linearly correlated within a certain concentration range and that the detection sensitivity of the sensor is extremely high. In the low concentration range of linear response, the kinetics of receptor-ligand interactions are similar to that of an enzymatic reaction. Among the investigated drug molecules, bromhexine exhibits the smallest Ka value, and thus, is most sensitively detected by the sensor. Hydroxychloroquine exhibits the largest Ka value. Molecular docking simulations of the spike protein with six small-molecule drugs show that residues of this protein, such as Asp, Trp, Asn, and Gln, form hydrogen bonds with the -OH or -NH2 groups on the branched chains of small-molecule drugs. The electrochemical receptor biosensor can directly quantify the interaction between the spike protein and drugs such as abidor and hydroxychloroquine and perform kinetic studies with a limit of detection 3.3 × 10-20 mol/L, which provides a new research method and idea for receptor-ligand interactions and pharmacodynamic evaluation.

Electrochemical Signal Amplification Strategies and Their Use in Olfactory and Taste Evaluation.

Biosensors are powerful analytical tools used to identify and detect target molecules. Electrochemical biosensors, which combine biosensing with electrochemical analysis techniques, are efficient analytical instruments that translate concentration signals into electrical signals, enabling the quantitative and qualitative analysis of target molecules. Electrochemical biosensors have been widely used in various fields of detection and analysis due to their high sensitivity, superior selectivity, quick reaction time, and inexpensive cost. However, the signal changes caused by interactions between a biological probe and a target molecule are very weak and difficult to capture directly by using detection instruments. Therefore, various signal amplification strategies have been proposed and developed to increase the accuracy and sensitivity of detection systems. This review serves as a reference for biosensor and detector research, as it introduces the research progress of electrochemical signal amplification strategies in olfactory and taste evaluation. It also discusses the latest signal amplification strategies currently being employed in electrochemical biosensors for nanomaterial development, enzyme labeling, and nucleic acid amplification techniques, and highlights the most recent work in using cell tissues as biosensitive elements.

Development of a sandwich-type rat small intestine tissue sensor for detecting resveratrol and its receptors.

Resveratrol has a variety of biological functions, however, a limited number of studies have assessed its interaction with cell surface receptors. In this study, a sandwich-type rat small intestine tissue sensor (RSIT-sensor) was fabricated to detect the response current from receptor stimulation by different resveratrol concentrations via electrochemical workstation. The results showed that with detection limit of 1 × 10-13 mol/L, the maximum rate of change of the response current was found at the concentration of 8.5 × 10-12 mol/L, indicating that the resveratrol-related receptor was saturated. With comparing the response values of prepared biosensor and bare electrode with resveratrol, it can be concluded that the response value of small intestinal cells to resveratrol has obviously been amplified by the intracellular signal transmission system, and its magnification was about 100 times. In the current research, for the first time, kinetics of the interaction between resveratrol and its receptors and the transmission of signals to the body could be quantitatively measured by a biosensor. Our findings may provide new ideas for resveratrol-related receptor analysis, separation and purification, signal transmission, and evaluation of biological function.

Os4BGlu14, a monolignol ß-Glucosidase, negatively affects seed longevity by influencing primary metabolism in rice.

KEY MESSAGE: Os4BGlu14, a monolignol ß-glucosidase, plays a negative role in seed longevity by affecting primary metabolism during seed development and aging. Seed longevity is a crucial trait in agriculture and in the conservation of germplasm resources. ß-Glucosidases (BGlus) are multifunctional enzymes that affect plant growth and their adaptation to the environment. The function of rice BGlus in seed longevity, however, remains unknown. We report here that Os4BGlu14, a rice ß-Glucosidase, negatively affected seed longevity during accelerated aging. Os4BGlu14 was highly expressed in rice embryos and induced by accelerated aging. Compared to the wild type, rice lines overexpressing Os4BGlu14 had significantly greater grain length, but smaller grain width and thickness. Overexpressing (OE) lines also showed lower starch but higher glucose contents. After accelerated aging treatment, OE lines displayed a significantly lower germination percentage than the wild type. Additionally, these lines had higher lignin accumulation before and after accelerated aging. Metabolome analysis detected 217 metabolites in untreated and aged rice seeds. Comparison of the differential metabolites between WT and OE5 revealed that ten key metabolites, four of which (e.g., uridine 5'-diphosphoglucose-glucose, UDPG) were increased, while the other six (e.g., γ-aminobutyric acid and methionine) were decreased, might be the crucial factors that lead to seed deterioration. Further analysis confirmed higher UDPG levels and more severe programmed cell death in OE lines than in the wild type. Furthermore, OE lines presented a lower germination rate after abscisic acid and paclobutrazol treatment during germination, compared to the wild type. Our study provides a basis for understanding the function of Os4BGlu14 in seed longevity in rice.

Development of a new and simple method for the detection of histidine-tagged proteins based on thionine-chitosan/gold nanoparticles/horseradish peroxidase.

In the current study, an electrochemical biosensing signal amplification system was utilized with thionine-chitosan-gold nanoparticles (Chit-GNPs) that absorbed horseradish peroxidase (HRP) and anti-His tagged protein monoclonal antibody derived from Balb/c mice. In addition, transmission electron microscopy (TEM) was used to characterize the nanogold solution and atomic force microscopy (AFM) was used to characterize the sensor assembly. To evaluate the quality of the immunosensor, the amperometric I-t curve method was applied to determine His-IL23 in PBS. The results indicated that the response current exhibited an optimal linear correlation with the His-IL23 concentration that ranged from 0.01 to 103 ng/ml. The lowest detection limit was noted at 3.3 pg/ml (S/N = 3). The linear equation was deduced as follows: △I = 0.02lgC + 0.037 (R2 = 0.9628). Moreover, it was validated with high sensitivity, reproducibility and rapid response. Apparently, the immunosensor may be a very useful tool for the detection and quantification of His-tagged proteins. In addition, the signal amplification system can be used for the preparation of other immunosensors and to assist in bioassays.

Chloroplastic Os3BGlu6 contributes significantly to cellular ABA pools and impacts drought tolerance and photosynthesis in rice.

Cellular abscisic acid (ABA) concentration is determined by both de novo biosynthesis and recycling via ß-glucosidase(s). However, which rice ß-glucosidase(s) are involved in this process remains unknown. Here, we report on a chloroplastic ß-glucosidase isoenzyme, Os3BGlu6, that functions in ABA recycling in rice. Disruption of Os3BGlu6 in rice resulted in dwarfism, lower ABA content in leaves, drought-sensitivity, lower photosynthesis rate and higher intercellular CO2 concentration. Os3BGlu6 could hydrolyze ABA-GE to ABA in vitro. The reversion and overexpression rice lines restored or increased the drought tolerance as shown by the higher ß-glucosidase activity, ABA concentrations and expressions of ABA- and drought-responsive genes. Drought induced Os3BGlu6 to form dimers, and the degree of polymerization correlated well with the increase in cellular ABA concentrations and drought tolerance in rice. Os3BGlu6 was responsive to drought and ABA treatments, and the protein was localized to the chloroplast. Disruption of Os3BGlu6 resulted in the increased stomatal density and impaired stomatal movement. Transcriptomics revealed that disruption of Os3BGlu6 resulted in chloroplastic oxidative stress and lowered Rubisco activity even under normal conditions. Taken together, these results suggest that chloroplastically localized Os3BGlu6 significantly affects cellular ABA pools, thereby affecting drought tolerance and photosynthesis in rice.

Specific roles of Os4BGlu10, Os6BGlu24, and Os9BGlu33 in seed germination, root elongation, and drought tolerance in rice.

MAIN CONCLUSION: Morphological, physiological, and gene expression analyses showed that Os4BGlu10, Os6BGlu24, and Os9BGlu33 played specific roles in seed germination, root elongation, and drought tolerance of rice, with various relations with indole-3-acetic acid (IAA) and abscisic acid (ABA) signaling. ß-Glucosidases (BGlus) belong to glycoside hydrolase family 1 and have many functions in plants. In this study, we investigated the function of three BGlus in seed germination, drought tolerance, and root elongation using the loss-of-function mutants bglu10, bglu24, and bglu33. These mutants germinated slightly later under normal conditions and had significantly longer roots than the wild type. In the presence of ABA, bglu10 and bglu24 exhibited a higher germination inhibition percentage, whereas bglu33 had a lower germination inhibition percentage, compared to the wild type. All of the mutants exhibited less drought tolerance, with the survival rates significantly lower than that of the wild type, which was also confirmed by a decrease in relative leaf water content and Fv/Fm ratio after drought treatment. The root length of bglu10 did not respond to IAA, whereas that of bglu24 responded to a high (0.25 µM) concentration of IAA, and that of bglu33 to a low (0.05 µM) concentration of IAA. The root length of bglu10 and bglu24 did not respond to ABA, whereas that of bglu33 increased significantly in response to a high (0.05 µM) concentration of ABA. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis showed that expression of Os4BGlu10 was up-regulated by polyethylene glycol (PEG), whereas that of Os6BGlu24 was up-regulated by 0.25 µM IAA, and Os9BGlu33 was up-regulated by PEG, IAA, and ABA. Taken together, we demonstrate that Os4BGlu10, Os6BGlu24, and Os9BGlu33 play specific roles in seed germination, root elongation, and drought tolerance with various relation with IAA and ABA signaling.