System Dynamics of the Water Droplet Impacting Flexible Cantilever Beams.

In this work, a water droplet impacting superhydrophobic flexible cantilever beams is systematically studied via experimental methods, aimed at recognizing the significance of the system dynamics that arises from the interplay between substrate oscillation and droplet impact. Influences of the substrate stiffness and the impact Weber number on the substrate oscillation and droplet impact dynamic are the focus particularly. For substrate oscillations, the beam deflection increases with the Weber number but decreases with the beam stiffness, while the oscillation period of the beam is not affected by the impact dynamic. For the droplet impact dynamic, the spreading dynamic is independent of beam oscillation, while the retraction dynamic is closely related to the surface elasticity. The effect of the cantilever beams on the droplet (i.e., promoting or inhibiting the rebound behavior) is dependent on the coupling movement of the water drop and the cantilever beam, which is varied by changing the stiffness of the cantilever beam. The findings of this work will provide a theoretical reference for the application of flexible substrates in the fields of anti-icing and self-cleaning.

Mobile Genetic Elements Contributing to Horizontal Gene Transfer of blaNDM among Escherichia coli in the community setting.

OBJECTIVE: To investigate the distribution of carbapenem-resistant Enterobacterales (CRE) in the community and to describe the genomic characteristics. METHODS: CRE screened from fecal samples in healthy people at the health examination center of a tertiary hospital in China underwent Whole genome sequencing (WGS) to analyze genotypic characteristics of CRE. The flanking DNA sequence of blaNDM-5 and mcr1.1 genes were analyzed by Gcluster software. RESULTS: A total of 7187 fecal samples were screened, and CRE carriage was detected in 0.4% of the sampled population. In total, 30 Escherichia coli, one Citrobacter freundii and one Klebsiella aerogene were screened. The 30 carbapenem-resistant Escherichia coli (CREC) isolates displayed slight resistance to amikacin (13.3%) and aztreonam (20.0%). All the CRE isolates contained blaNDM, and blaNDM-5 (84.4%) was the most common one. B1 (n=11) and A (n=7) were predominant phylogroups. Furthermore, 34 distinct plasmid replicons, 67 different VFs, 22 distinct STs, 17 different FimH types, 26 O:H serotypes as well as 74 MGEs including 61 insertion sequences and 13 transposons were identified. The flanking DNA sequence analysis of blaNDM-5 and mcr1.1 genes indicates the key role of horizontal transfer of blaNDM-5 in the CRE development evidenced by diverse STs and phylogenetic tree. CONCLUSION: E. coli was the most predominant CRE isolates in community setting, and blaNDM (blaNDM-5) was the main CHßL encoding genes. The high prevalence of ARGs was associated with high resistance to commonly used antimicrobials. Besides, the genetic diversity of these isolates suggested the key role of blaNDM horizontal transfer in the CRE development. Thus, active screening of blaNDM in communities is particularly important for the prevention and control of CRE.

Cardiomyocyte-derived circulating extracellular vesicles allow a non-invasive liquid biopsy of myocardium in health and disease.

The ability to track disease without tissue biopsy in patients is a major goal in biology and medicine. Here, we identify and characterize cardiomyocyte-derived extracellular vesicles in circulation (EVs; "cardiovesicles") through comprehensive studies of induced pluripotent stem cell-derived cardiomyocytes, genetic mouse models, and state-of-the-art mass spectrometry and low-input transcriptomics. These studies identified two markers ( POPDC2 , CHRNE ) enriched on cardiovesicles for biotinylated antibody-based immunocapture. Captured cardiovesicles were enriched in canonical cardiomyocyte transcripts/pathways with distinct profiles based on human disease type (heart failure, myocardial infarction). In paired myocardial tissue-plasma from patients, highly expressed genes in cardiovesicles were largely cardiac-enriched (vs. "bulk" EVs, which were more organ non-specific) with high expression in myocardial tissue by single nuclear RNA-seq, largely in cardiomyocytes. These results demonstrate the first "liquid" biopsy discovery platform to interrogate cardiomyocyte states non-invasively in model systems and in human disease, allowing non-invasive characterization of cardiomyocyte biology for discovery and therapeutic applications.

N6-methyladenosine transcriptome-wide profiles of maize kernel development.

Maize (Zea mays L.) kernel development is a complex and dynamic process involving cell division and differentiation, into a variety of cell types. Epigenetic modifications, including DNA methylation, play a pivotal role in regulating this process. N6-methyladenosine modification is a universal and dynamic post-transcriptional epigenetic modification that is involved in the regulation of plant development. However, the role of N6-methyladenosine in maize kernel development remains unknown. In this study, we have constructed transcriptome-wide profiles for maize kernels at various stages of early development. Utilizing a combination of MeRIP-seq and RNA-seq analysis, we identified a total of 11,170, 10,973, 11,094, 11,990, 12,203 and 10,893 N6-methyladenosine peaks in maize kernels at 0, 2, 4, 6, 8, and 12 days after pollination, respectively. These N6-methyladenosine modifications were primarily deposited at the 3'-UTRs and were associated with the conserved motif-UGUACA. Additionally, we found that conserved N6-methyladenosine modification are involved in the regulation of genes that are ubiquitously expressed during kernel development. Further analysis revealed that N6-methyladenosine peak intensity was negatively correlated with the mRNA abundance of these ubiquitously expressed genes. Meanwhile, we employed phylogenetic analysis to predict potential regulatory proteins involved in maize kernels development and identified several that participate in the regulation of N6-methyladenosine modifications. Collectively, our results suggest the existence of a novel post-transcriptional epigenetic modification mechanism involved in the regulation of maize kernels development, thereby providing a novel perspective for maize molecular breeding.

Ablation for Atrial Fibrillation in Patients With Rare Pathogenic Variants in Cardiomyopathy and Arrhythmia Genes.

BACKGROUND: Patients with rare, pathogenic cardiomyopathy (CM) and arrhythmia variants can present with atrial fibrillation (AF). The efficacy of AF ablation in these patients is unknown. OBJECTIVE: This study tested the hypotheses that: 1) patients with a pathogenic variant in any CM or arrhythmia gene have increased recurrence following AF ablation; and 2) patients with a pathogenic variant associated with a specific gene group (arrhythmogenic left ventricular CM [ALVC], arrhythmogenic right ventricular CM, dilated CM, hypertrophic CM, or a channelopathy) have increased recurrence. METHODS: We performed a prospective, observational, cohort study of patients who underwent AF catheter ablation and whole exome sequencing. The primary outcome measure was ≥30 seconds of any atrial tachyarrhythmia that occurred after a 90-day blanking period. RESULTS: Among 1,366 participants, 109 (8.0%) had a pathogenic or likely pathogenic (P/LP) variant in a CM or arrhythmia gene. In multivariable analysis, the presence of a P/LP variant in any gene was not significantly associated with recurrence (HR 1.15; 95% CI 0.84-1.60; P = 0.53). P/LP variants in the ALVC gene group, predominantly LMNA, were associated with increased recurrence (n = 10; HR 3.75; 95% CI 1.84-7.63; P < 0.001), compared with those in the arrhythmogenic right ventricular CM, dilated CM, hypertrophic CM, and channelopathy gene groups. Participants with P/LP TTN variants (n = 46) had no difference in recurrence compared with genotype-negative-controls (HR 0.93; 95% CI 0.54-1.59; P = 0.78). CONCLUSIONS: Our results support the use of AF ablation for most patients with rare pathogenic CM or arrhythmia variants, including TTN. However, patients with ALVC variants, such as LMNA, may be at a significantly higher risk for arrhythmia recurrence.

Two 2D spin-crossover coordination polymers constructed by [Pd(SCN)4]2- building blocks.

Two new two-dimensional (2D) coordination polymers, [FeII(L)2{PdII(SCN)4}] (L1 = 2-methoxypyrazine, 1; and L2 = (E)-3-(phenyldiazenyl)pyridine, 2), were successfully constructed by using square-planar [Pd(SCN)4]2- building blocks. Complex 1 exhibits complete and one-step spin-crossover (SCO) behavior, while 2 exhibits incomplete and two-step SCO behavior. Further structural insight into this synergy reveals that the flat/flexing [Fe{Pd(SCN)4}]∞ sheets in 1 and 2 are stabilized by interlayered/intralayered supramolecular interactions.

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated encephalitis induced by Mycoplasma pneumoniae infections.

BACKGROUND: This study aims to report the phenomenon of Myelin oligodendrocyte glycoprotein antibody-associated encephalitis induced by Mycoplasma pneumoniae infections and promote the potential benefits of combining early immunotherapy and anti-M-pneumoniae therapy for these patients. METHODS: Three children with MOG-IgG-associated encephalitis due to M. pneumoniae infections who were treated at our hospital from September to November 2023 were included in the study. We investigated and analyzed the background and clinical features of these patients. RESULTS: Three patients developed headaches, seizures, and/or other neurological manifestations, elevated mononuclear cells in cerebrospinal fluid, intracranial lesions on cranial magnetic resonance imaging (MRI), and positive MOG-IgG in serum, within 10-14 days. They were diagnosed with MOG-IgG-associated encephalitis due to M. pneumoniae infections, the treatment consisted of intravenous immunoglobulin, glucocorticoid, and erythromycin, then they were completely recovered. CONCLUSION: Mycoplasma pneumoniae (M. pneumoniae) infections can cause oligodendrocyte glycoprotein (MOG) antibody-associated encephalitis. The recognition of this condition will promote the potential benefits of combining early immunotherapy and anti-M. pneumoniae therapy for patients with MOG-IgG-associated encephalitis.

Potential for trans-pulmonary tumor markers in the early diagnosis of lung cancer: a case report.

BACKGROUND: Measurement of tumor markers from peripheral venous blood is an emerging tool to assist in the early diagnosis of lung cancer. Samples from the pulmonary artery and pulmonary artery wedge position (trans-pulmonary samples) are accessible via right-heart catheterization and, by virtue of their proximity to lung tumors, may increase diagnostic yield. CASE PRESENTATION: We report a case of a 64 year-old woman from whom trans-pulmonary samples were obtained and who was diagnosed 16 months later with recurrent metastatic small cell lung cancer. Carcinoembryonic antigen, cytokeratin fragment 21 - 1 (CYFRA), and human epididymis protein 4 (HE4) levels demonstrated increasing concentrations across the pulmonary circulation. These gradients exceeded the assays' coefficient of variation by several-fold. For CYFRA and HE4, pulmonary artery wedge concentrations exceeded peripheral venous levels by more than 10% and peripheral arterial levels were up to 8% higher than peripheral venous levels. CONCLUSIONS: Evaluating the feasibility and utility of trans-pulmonary tumor markers for lung cancer diagnosis in a larger cohort should be considered. The addition of a peripheral arterial sample to standard peripheral venous samples may be a more practical alternative.

Timing of percutaneous coronary intervention and risk of new-onset acute ischemic stroke in non-ST elevation myocardial infarction: A retrospective cohort study insight into the National Inpatient Sample Database (2016-2019).

Background and Aims: For patients with high-risk non-ST elevation myocardial infarction (NSTEMI), current guidelines recommend an early invasive strategy within 24 h. New-onset acute ischemic stroke (NAIS) is a rare but fatal complication of percutaneous coronary intervention (PCI). However, the effect of the timing of PCI and the risk of NAIS in NSTEMI is poorly defined. Methods: Patients with NSTEMI who underwent PCI were queried from the National Inpatient Sample Database (2016-2019) and stratified into three groups: early (<24 h), medium (24-72 h), and late (>72 h) PCI. Multivariate logistic regression models were used to determine the association between timing of PCI and NAIS. Results: Among 633,115 weighted hospitalizations, patients in the late PCI group had a higher incidence of NAIS (1.3%) than those in the early (0.67%) and medium (0.71%) PCI groups. Patients undergoing late PCI were older, more likely to be female, and had a greater incidence of comorbidities (e.g., diabetes mellitus, chronic pulmonary and renal illness, and atrial fibrillation) than those undergoing early or medium PCI. After adjustment, only late PCI was significantly associated with a 54% increased NAIS risk (adjusted odds ratio: 1.54 [95% confidence interval: 1.29-1.84]). Additionally, there was heterogeneity in the magnitude of risk by age and sex. Younger people (<65 years) (p for interaction <0.001) and men (interaction-value p = 0.040) were more likely to encounter NAIS. Conclusion: Late PCI was associated with a higher risk of NAIS than early PCI, particularly among men and those aged <65 years.

The transcription factor RppA regulates chlorophyll and carotenoid biosynthesis to improve photoprotection in cyanobacteria.

Chlorophyll is an essential photosynthetic pigment but also a strong photosensitizer. Excessive free chlorophyll and its precursors can cause oxidative damage to photosynthetic organisms. Cyanobacteria are the oldest oxygenic photosynthetic organisms and the ancestors of the chloroplast. Owing to their complex habitats, cyanobacteria require precise regulation of chlorophyll synthesis to respond to environmental factors, especially changes in light. Chlorophyll synthase, encoded by chlG, is the enzyme catalyzing the final step of chlorophyll biosynthesis, which is closely related to photosynthesis biogenesis. However, the transcriptional regulation on chlG remains unclear. Here, the transcription factor, regulator of photosynthesis and photopigment-related gene expression A (RppA) was identified to bind to the chlG promoter by screening a yeast one-hybrid library in the cyanobacterium Synechocystis sp. PCC 6803. The rppA knock-out mutant showed a phenotype of slow growth and severe oxidative damage under dark-light transition conditions. The up-regulated transcriptional expression of chlG was significantly higher and more chlorophyll and its precursors accumulated in the rppA knock-out mutant than those in the wild-type strain during the transition from darkness to light, indicating RppA represses the expression of chlG in Synechocystis. Meanwhile, RppA could synchronously promote the transcription of carotenoids biosynthesis-related genes to enhance carotenoids synthesis during the dark-light transition. These results reveal synergistic regulation of chlorophyll and carotenoids biosynthesis in cyanobacteria in response to frequent dark-light transitions, which slows down chlorophyll biosynthesis while promoting carotenoids biosynthesis to avoid oxidative damage caused by excessive reactive oxygen species accumulation.

Release of intracellular enzymes increases the total extracellular activities of carbohydrate processing enzymes in marine environment.

Microbial extracellular enzymatic activities (EEAs) produced by microbes to degrade biopolymers are the 'gatekeeper' of carbon cycle in the marine ecosystem. It is usually assumed that these extracellular enzymes are actively secreted by microbes. But biopolymers degrading enzymes also exist in the intracellular space. Cell lysis will passively release these enzymes into the environments and contribute to the total EEAs. However, to what extent the cell lysis can contribute to the total EEAs are still unclear. Here, using extreme cell lysis method, we evaluated the maximum contribution of cell lysis to total EEAs in culturable marine bacteria and coastal seawater. For carbohydrate processing enzymes (ß-glucosidase, alginate lyase and chitinase), the release of intracellular enzymes could contribute positively (up to 56.1% increase for ß-glucosidase in seawater) to the total EEAs. For protease and leucine aminopeptidase, the cell lysis did not increase and even decreased the total EEAs. For alkaline phosphatase, the intracellular enzymes generally had no contribution to the total EEAs. These results showed that passively released intracellular enzymes could substantially increase the total extracellular activities of carbohydrate processing enzymes, which should be considered in building the link between the EEAs and organic carbon cycle in the ocean.

Depression Takes a Toll on Academic Performance: Evidence from Rural Students in China.

Purpose: Depression is a growing public health concern around the world. For adolescents, depression not only impedes healthy development, but is negatively associated with academic performance. The purpose of this paper is to examine the prevalence of adolescent depressive symptoms in a sample of rural primary and junior high school students. Additionally, we examine various factors to identify subgroups within the sample that may be more vulnerable to depression. Finally, we explore the extent to which depression correlates with academic performance and conduct a series of heterogeneity analyses. Patients and Methods: We utilize cross-sectional data derived from 30 schools in underdeveloped regions of rural China encompassing primary and junior high school students (n = 1,609). Results: We find a high prevalence of depression, with 23% and 9% of students experiencing general depression (depression score ≥ 14) and severe depression (depression score ≥ 21), respectively. Female gender, elevated stress and anxiety levels, boarding at school, exposure to bullying, and having depressed caregiver(s) are positively correlated with depressive symptoms, while high social support exhibits a negative association. Importantly, our analyses consistently show a significantly negative link between depression and academic performance, which is measured using standardized math tests. For instance, transitioning from a non-depressed state to a state of general depression (depression score ≥ 14) is linked to a decline of 0.348-0.406 standard deviations in math scores (p < 0.01). Heterogeneity analyses reveal that this adverse relationship is more pronounced for male students, boarding students, those with lower social support, individuals with more educated mothers, and those with lower family assets. Conclusion: Our findings underscore the high prevalence of depression in rural schools and the detrimental impact on academic performance. We advocate for the implementation of policies aimed at reducing student depression, particularly within vulnerable populations and subgroups.

Gßγ dimers mediate low K+ stress-inhibited root growth via modulating auxin redistribution in Arabidopsis.

In the investigation of heterotrimeric G protein-mediated signal transduction in planta, their roles in the transmittance of low K+ stimuli remain to be elucidated. Here, we found that the primary root growth of wild-type Arabidopsis was gradually inhibited with the decrease of external K+ concentrations, while the primary root of the mutants for G protein ß subunit AGB1 and γ subunits AGG1, AGG2 and AGG3 could still grow under low K+ conditions (LK). Exogenous NAA application attenuated primary root elongation in agb1 and agg1/2/3 but promoted the growth in wild-type seedlings under LK stress. Using ProDR5:GFP, ProPIN1:PIN1-GFP and ProPIN2:PIN2-GFP reporter lines, a diminishment in auxin concentration at the radicle apex and a reduction in PIN1and PIN2 efflux carrier abundance were observed in wild-type roots under LK, a phenomenon not recorded in the agb1 and agg1/2/3. Further proteolytic and transcriptional assessments revealed an enhanced degradation of PIN1 and a suppressed expression of PIN2 in the wild-type background under LK, contrasting with the stability observed in the agb1 and agg1/2/3 mutants. Our results indicate that the G protein ß and γ subunits play pivotal roles in suppressing of Arabidopsis root growth under LK by modulating auxin redistribution via alterations in PIN1 degradation and PIN2 biosynthesis.

Seroreactivity against Leptospira spp. differs between community cats and privately-owned cats in Hong Kong.

Leptospirosis is a bacterial zoonotic disease of major One Health significance and public health impact globally, with a wide host range including mammals, cetaceans and herpetofauna. This study aimed to determine Leptospira seroprevalence, risk factors for seroreactivity and prevalence of urinary Leptospira shedding among domestic cats in Hong Kong. Microagglutination testing of 22 Leptospira serovars from 20 serogroups was performed on 738 sera from outdoor free-roaming "community" cats (n = 391) and privately-owned (n = 347) cats. Urine from 268 community cats was tested for pathogenic Leptospira DNA by qPCR targeting lipL32. Potential risk factors associated with exposure were assessed using logistic regression. Overall Leptospira seroprevalence was 9.35%. Of 14 serogroups detected, Javanica (4.3%), Djasiman (2.3%) and Australis (1.5%) were most common. Seroreactivity was significantly higher among community (13.3%) than privately-owned cats (4.9%; OR 2.98 [95% CI 1.68-5.25], P < 0.001), especially to Javanica (7.65% of community cats versus 0.58% of privately-owned cats (P < 0.001). Antibody titres to all serogroups ranged from 1:100 to 1:6400 (median 1:200) and were highest for Javanica (median 1:800). Leptospira DNA was detected in urine from 12/268 community cats (4.48%; median load 6.42 × 102 copies/mL urine; range 1.40 × 101-9.63 × 104). One in three seroreactive community cats with paired urine and blood samples had leptospiruria. After adjusting for source, none of breed, sex, neuter status, age, district rodent infestation rate, serum alanine transaminase or creatinine values were associated with seroreactivity. Cats in Hong Kong are exposed to a diversity of Leptospira serogroups and can shed Leptospira silently in urine. The higher seroprevalence among outdoor free-roaming community cats highlights the importance of environmental drivers in leptospirosis transmission and risks of exposure for sympatric human populations. Gloves should be worn when handling feline urine to minimise the risk of zoonotic transmission from subclinically infected cats.

Treating chronic atrophic gastritis: identifying sub-population based on real-world TCM electronic medical records.

Background and Objective: Chronic atrophic gastritis (CAG) is a complex chronic disease caused by multiple factors that frequently occurs disease in the clinic. The worldwide prevalence of CAG is high. Interestingly, clinical CAG patients often present with a variety of symptom phenotypes, which makes it more difficult for clinicians to treat. Therefore, there is an urgent need to improve our understanding of the complexity of the clinical CAG population, obtain more accurate disease subtypes, and explore the relationship between clinical symptoms and medication. Therefore, based on the integrated platform of complex networks and clinical research, we classified the collected patients with CAG according to their different clinical characteristics and conducted correlation analysis on the classification results to identify more accurate disease subtypes to aid in personalized clinical treatment. Method: Traditional Chinese medicine (TCM) offers an empirical understanding of the clinical subtypes of complicated disorders since TCM therapy is tailored to the patient's symptom profile. We gathered 6,253 TCM clinical electronic medical records (EMRs) from CAG patients and manually annotated, extracted, and preprocessed the data. A shared symptom-patient similarity network (PSN) was created. CAG patient subgroups were established, and their clinical features were determined through enrichment analysis employing community identification methods. Different clinical features of relevant subgroups were correlated based on effectiveness to identify symptom-botanical botanical drugs correspondence. Moreover, network pharmacology was employed to identify possible biological relationships between screened symptoms and medications and to identify various clinical and molecular aspects of the key subtypes using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Results: 5,132 patients were included in the study: 2,699 males (52.60%) and 2,433 females (47.41%). The population was divided into 176 modules. We selected the first 3 modules (M29, M3, and M0) to illustrate the characteristic phenotypes and genotypes of CAG disease subtypes. The M29 subgroup was characterized by gastric fullness disease and internal syndrome of turbidity and poison. The M3 subgroup was characterized by epigastric pain and disharmony between the liver and stomach. The M0 subgroup was characterized by epigastric pain and dampness-heat syndrome. In symptom analysis, The top symptoms for symptom improvement in all three subgroups were stomach pain, bloating, insomnia, poor appetite, and heartburn. However, the three groups were different. The M29 subgroup was more likely to have stomach distention, anorexia, and palpitations. Citrus medica, Solanum nigrum, Jiangcan, Shan ci mushrooms, and Dillon were the most popular botanical drugs. The M3 subgroup has a higher incidence of yellow urine, a bitter tongue, and stomachaches. Smilax glabra, Cyperus rotundus, Angelica sinensis, Conioselinum anthriscoides, and Paeonia lactiflora were the botanical drugs used. Vomiting, nausea, stomach pain, and appetite loss are common in the M0 subgroup. The primary medications are Scutellaria baicalensis, Smilax glabra, Picrorhiza kurroa, Lilium lancifolium, and Artemisia scoparia. Through GO and KEGG pathway analysis, We found that in the M29 subgroup, Citrus medica, Solanum nigrum, Jiangcan, Shan ci mushrooms, and Dillon may exert their therapeutic effects on the symptoms of gastric distension, anorexia, and palpitations by modulating apoptosis and NF-κB signaling pathways. In the M3 subgroup, Smilax glabra, Cyperus rotundus, Angelica sinensis, Conioselinum anthriscoides, and Paeonia lactiflora may be treated by NF-κB and JAK-STAT signaling pathway for the treatment of stomach pain, bitter mouth, and yellow urine. In the M0 subgroup, Scutellaria baicalensis, Smilax glabra, Picrorhiza kurroa, Lilium lancifolium, and Artemisia scoparia may exert their therapeutic effects on poor appetite, stomach pain, vomiting, and nausea through the PI3K-Akt signaling pathway. Conclusion: Based on PSN identification and community detection analysis, CAG population division can provide useful recommendations for clinical CAG treatment. This method is useful for CAG illness classification and genotyping investigations and can be used for other complicated chronic diseases.

Chemical Isotope Labeling and Dual-Filtering Strategy for Comprehensive Profiling of Urinary Glucuronide Conjugates.

Glucuronidation, a crucial process in phase II metabolism, plays a vital role in the detoxification and elimination of endogenous substances and xenobiotics. A comprehensive and confident profiling of glucuronate-conjugated metabolites is imperative to understanding their roles in physiological and pathological processes. In this study, a chemical isotope labeling and dual-filtering strategy was developed for global profiling of glucuronide metabolites in biological samples. N,N-Dimethyl ethylenediamine (DMED-d0) and its deuterated counterpart DMED-d6 were used to label carboxylic acids through an amidation reaction. First, carboxyl-containing compounds were extracted based on a characteristic mass difference (Δm/z, 6.037 Da) observed in MS between light- and heavy-labeled metabolites (filter I). Subsequently, within the pool of carboxyl-containing compounds, glucuronides were identified using two pairs of diagnostic ions (m/z 247.1294/253.1665 and 229.1188/235.1559 for DMED-d0/DMED-d6-labeled glucuronides) originating from the fragmentation of the derivatized glucuronic acid group in MS/MS (filter II). Compared with non-derivatization, DEMD labeling significantly enhanced the detection sensitivity of glucuronides, as evidenced by a 3- to 55-fold decrease in limits of detection for representative standards. The strategy was applied to profiling glucuronide metabolites in urine samples from colorectal cancer (CRC) patients. A total of 685 features were screened as potential glucuronides, among which 181 were annotated, mainly including glucuronides derived from lipids, organic oxygen, and phenylpropanoids. Enzymatic biosynthesis was employed to accurately identify unknown glucuronides without standards, demonstrating the reliability of the dual-filtering strategy. Our strategy exhibits great potential for profiling the glucuronide metabolome with high coverage and confidence to reveal changes in CRC and other diseases.

Nitric oxide mediates positive regulation of Nostoc flagelliforme polysaccharide yield via potential S-nitrosylation of G6PDH and UGDH.

Based on our previous findings that salicylic acid and jasmonic acid increased Nostoc flagelliforme polysaccharide yield by regulating intracellular nitric oxide (NO) levels, the mechanism through which NO affects polysaccharide biosynthesis in Nostoc flagelliforme was explored from the perspective of S-nitrosylation (SNO). The addition of NO donor and scavenger showed that intracellular NO had a significant positive effect on the polysaccharide yield of N. flagelliforme. To explore the mechanism, we investigated the relationship between NO levels and the activity of several key enzymes involved in polysaccharide biosynthesis, including fructose 1,6-bisphosphate aldolase (FBA), glucokinase (GK), glucose 6-phosphate dehydrogenase (G6PDH), mitochondrial isocitrate dehydrogenase (ICDH), and UDP-glucose dehydrogenase (UGDH). The enzymatic activities of G6PDH, ICDH, and UGDH were shown to be significantly correlated with the shifts in intracellular NO levels. For further validation, G6PDH, ICDH, and UGDH were heterologously expressed in Escherichia coli and purified via Ni+-NAT affinity chromatography, and subjected to a biotin switch assay and western blot analysis, which revealed that UGDH and G6PDH were susceptible to SNO. Furthermore, mass spectrometry analysis of proteins treated with S-nitrosoglutathione (GSNO) identified the SNO modification sites for UGDH and G6PDH as cysteine 423 and cysteine 249, respectively. These findings suggest that NO modulates polysaccharide biosynthesis in N. flagelliforme through SNO of UGDH and G6PDH. This reveals a potential mechanism through which NO promotes polysaccharide synthesis in N. flagelliforme, while also providing a new strategy for improving the industrial production of polysaccharides.

Red-light-dependent chlorophyll synthesis kindles photosynthetic recovery of chlorotic dormant cyanobacteria using a dark-operative enzyme.

Chlorosis dormancy resulting from nitrogen starvation and its resuscitation upon available nitrogen contributes greatly to the fitness of cyanobacterial population under nitrogen-fluctuating environments. The reinstallation of the photosynthetic machinery is a key process for resuscitation from a chlorotic dormant state; however, the underlying regulatory mechanism is still elusive. Here, we reported that red light is essential for re-greening chlorotic Synechocystis sp. PCC 6803 (a non-diazotrophic cyanobacterium) after nitrogen supplement under weak light conditions. The expression of dark-operative protochlorophyllide reductase (DPOR) governed by the transcriptional factor RpaB was strikingly induced by red light in chlorotic cells, and its deficient mutant lost the capability of resuscitation from a dormant state, indicating DPOR catalyzing chlorophyll synthesis is a key step in the photosynthetic recovery of dormant cyanobacteria. Although light-dependent protochlorophyllide reductase is widely considered as a master switch in photomorphogenesis, this study unravels the primitive DPOR as a spark to activate the photosynthetic recovery of chlorotic dormant cyanobacteria. These findings provide new insight into the biological significance of DPOR in cyanobacteria and even some plants thriving in extreme environments.

Association between PER and CRY gene polymorphisms and the response to caffeine citrate treatment in infants with apnea of prematurity.

Background: Circadian rhythms impact metabolism and the therapeutic effects of drugs. The purpose of this study was to determine the association between PER and CRY polymorphisms and caffeine citrate treatment response in infants with apnea of prematurity. Methods: A total of 221 preterm infants of gestational age <34 weeks were included in this study (160 in the response group and 61 in the non-response group). The propensity score matching method was used to perform a 1:1 matching for all premature infants, and the general characteristics and clinical outcomes of the two groups were compared. The association between polymorphisms of the circadian transcription repressors PER and CRY and caffeine citrate treatment response in infants with apnea of prematurity was analyzed with co-dominant, dominant, recessive, and over-dominant models, as well as analysis of alleles. Generalized multifactor dimensionality reduction (GMDR) analysis was used to analyze the interaction between the PER and CRY genes. Results: After propensity score matching, 45 preterm infants were included in each of the response and non-response groups, and there were no statistically significant differences in general characteristics between the two groups (P > 0.05). Infants in the non-response groups had a higher incidence of moderate and severe bronchopulmonary dysplasia (BPD) (P = 0.043), retinopathy of prematurity (ROP) (P = 0.035), and invasive ventilation (P = 0.027), and their duration of oxygen use (P = 0.041) was longer. When corrected for false discovery rate, the PER3 rs228669 recessive model (P FDR = 0.045) and the over-dominant model (P FDR = 0.045) were both associated with caffeine citrate treatment response. Preterm infants with the rs228669 CC genotype had a significantly lower rate of caffeine citrate non-response in the recessive model (OR = 0.28, 95% CI = 0.12-0.66), which was significantly higher in preterm infants with the CT genotype in the over-dominant model (OR = 4.18, 95% CI = 1.64-10.66). GMDR analysis revealed an interaction between the PER and CRY genes (P < 0.05). Conclusions: Circadian rhythms may play a role in the response of premature infants to caffeine citrate, and polymorphisms of the PER and CRY genes may influence the effectiveness of caffeine citrate treatment for apnea of prematurity.