Genomic and Metagenomic Insights into the Distribution of Nicotine-degrading Enzymes in Human Microbiota.

Introduction: Nicotine degradation is a new strategy to block nicotine-induced pathology. The potential of human microbiota to degrade nicotine has not been explored. Aims: This study aimed to uncover the genomic potentials of human microbiota to degrade nicotine. Methods: To address this issue, we performed a systematic annotation of Nicotine-Degrading Enzymes (NDEs) from genomes and metagenomes of human microbiota. A total of 26,295 genomes and 1,596 metagenomes for human microbiota were downloaded from public databases and five types of NDEs were annotated with a custom pipeline. We found 959 NdhB, 785 NdhL, 987 NicX, three NicA1, and three NicA2 homologs. Results: Genomic classification revealed that six phylum-level taxa, including Proteobacteria, Firmicutes, Firmicutes_A, Bacteroidota, Actinobacteriota, and Chloroflexota, can produce NDEs, with Proteobacteria encoding all five types of NDEs studied. Analysis of NicX prevalence revealed differences among body sites. NicX homologs were found in gut and oral samples with a high prevalence but not found in lung samples. NicX was found in samples from both smokers and non-smokers, though the prevalence might be different. Conclusion: This study represents the first systematic investigation of NDEs from the human microbiota, providing new insights into the physiology and ecological functions of human microbiota and shedding new light on the development of nicotine-degrading probiotics for the treatment of smoking-related diseases.

Development of synthetic modulator enabling long-term propagation and neurogenesis of human embryonic stem cell-derived neural progenitor cells.

Neural progenitor cells (NPCs) are essential for in vitro drug screening and cell-based therapies for brain-related disorders, necessitating well-defined and reproducible culture systems. Current strategies employing protein growth factors pose challenges in terms of both reproducibility and cost. In this study, we developed a novel DNA-based modulator to regulate FGFR signaling in NPCs, thereby facilitating the long-term maintenance of stemness and promoting neurogenesis. This DNA-based FGFR-agonist effectively stimulated FGFR1 phosphorylation and activated the downstream ERK signaling pathway in human embryonic stem cell (HESC)-derived NPCs. We replaced the basic fibroblast growth factor (bFGF) in the culture medium with our DNA-based FGFR-agonist to artificially modulate FGFR signaling in NPCs. Utilizing a combination of cell experiments and bioinformatics analyses, we showed that our FGFR-agonist could enhance NPC proliferation, direct migration, and promote neurosphere formation, thus mimicking the functions of bFGF. Notably, transcriptomic analysis indicated that the FGFR-agonist could specifically influence the transcriptional program associated with stemness while maintaining the neuronal differentiation program, closely resembling the effects of bFGF. Furthermore, our culture conditions allowed for the successful propagation of NPCs through over 50 passages while retaining their ability to efficiently differentiate into neurons. Collectively, our approach offers a highly effective method for expanding NPCs, thereby providing new avenues for disease-in-dish research and drug screening aimed at combating neural degeneration.

Functional Characterization of An Allene Oxide Synthase Involved in Biosynthesis of Jasmonic Acid and Its Influence on Metabolite Profiles and Ethylene Formation in Tea (Camellia sinensis) Flowers.

Jasmonic acid (JA) is reportedly involved in the interaction between insects and the vegetative parts of horticultural crops; less attention has, however, been paid to its involvement in the interaction between insects and the floral parts of horticultural crops. Previously, we investigated the allene oxide synthase 2 (AOS2) gene that was found to be the only JA synthesis gene upregulated in tea (Camellia sinensis) flowers exposed to insect (Thrips hawaiiensis (Morgan)) attacks. In our present study, transient expression analysis in Nicotiana benthamiana plants confirmed that CsAOS2 functioned in JA synthesis and was located in the chloroplast membrane. In contrast to tea leaves, the metabolite profiles of tea flowers were not significantly affected by 10 h JA (2.5 mM) treatment as determined using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry, and gas chromatography-mass spectrometry. Moreover, JA treatment did not significantly influence ethylene formation in tea flowers. These results suggest that JA in tea flowers may have different functions from JA in tea leaves and other flowers.

Elucidation of Differential Accumulation of 1-Phenylethanol in Flowers and Leaves of Tea (Camellia sinensis) Plants.

1-Phenylethanol (1PE) is a major aromatic volatile in tea (Camellia sinensis) flowers, whereas it occurs in a much smaller amounts in leaves. Enzymes involved in the formation of 1PE in plants and the reason why 1PE differentially accumulates in plants is unknown. In the present study, enzymes in the last step leading from acetophenone to 1PE were isolated from tea flowers by traditional biochemical chromatography. The two types of partially purified enzymes were proposed to be responsible for formations of (R)-1PE and (S)-1PE, respectively. Tea leaves also contained such enzymes having equivalent activities with flowers. Stable isotope labeling experiments indicated that weak transformation from l-phenylalanine to acetophenone in leaves mainly resulted in little occurrence of 1PE in leaves. This study provided an example that differential distribution of some metabolites in plant tissues was not only determined by enzyme(s) in the last step of metabolite formation, but also can be due to substrate availability.

A novel method for evaluating load restraint assemblies to ensure the safety of railway freight transportation.

The violent goods vibration during curve negotiation is a huge threat to the vehicle running safety. Qualified load restraint assemblies that can significantly suppress the cargo vibration are necessary. This study proposes a novel method for evaluating the essential restraint strength, focusing on the relative motion between cargo and wagon. In the beginning, as a comparison, current methods are used to calculate the necessary stiffness of lashings, which are adopted to restrain the cargo vibration on the wagon. Based on the data of the field test, the accuracy of the established wagon-cargo coupled dynamics model is validated. The loaded wagon model negotiates the curve under different running and loading conditions. The simulation results and analysis demonstrate effective strategies for suppressing the vibration of the cargo and reveal the necessary lashing stiffness. The comparison among the results of different evaluation methods shows that the stability of the cargo can be improved by optimizing the lashing stiffness with the method of dynamics simulations. We hope this study will make a positive contribution to the safety of railway freight transportation.

Coexistence of Ferromagnetism and Ferroelectricity in Cu-Intercalated Bilayer CrI3.

Design of two-dimensional (2D) multiferroic materials with two or more ferroic orders in one structure is highly desired in view of the development of next-generation electronic devices. Unfortunately, experimental or theoretical discovery of 2D intrinsic multiferroic materials is rare. Using first-principles calculation methods, we report the realization of multiferroics that couple ferromagnetism and ferroelectricity by intercalating Cu atoms in bilayer CrI3, Cux@bi-CrI3 (x = 0.03, 0.06, and 0.25). Our results show that the intercalation of Cu atoms leads to the inversion symmetry breaking of bilayer CrI3 and produces intercalation density-dependent out-of-plane electric polarization, around 18.84-90.31 pC·cm-2. Moreover, the switch barriers of Cux@bi-CrI3 in both polarization states are small, ranging from 0.31 to 0.69 eV. Furthermore, the magnetoelectric coupling properties of Cux@bi-CrI3 can be modulated via varying the metal ion intercalation density, and half-metal to semiconductor transition can be occurred by decreasing the intercalation density of metal ions. Our work paves a practical path for 2D magnetoelectron coupling devices.

Mendelian randomization analyses of smoking and Alzheimer's disease in Chinese and Japanese populations.

Background: Previous epidemiological studies have reported controversial results on the relationship between smoking and Alzheimer's disease (AD). Therefore, we sought to assess the association using Mendelian randomization (MR) analysis. Methods: We used single nucleotide polymorphisms (SNPs) associated with smoking quantity (cigarettes per day, CPD) from genome-wide association studies (GWAS) of Japanese population as instrumental variables, then we performed two-sample MR analysis to investigate the association between smoking and AD in a Chinese cohort (1,000 AD cases and 500 controls) and a Japanese cohort (3,962 AD cases and 4,074 controls), respectively. Results: Genetically higher smoking quantity showed no statistical causal association with AD risk (the inverse variance weighted (IVW) estimate in the Chinese cohort: odds ratio (OR) = 0.510, 95% confidence interval (CI) = 0.149-1.744, p = 0.284; IVW estimate in the Japanese cohort: OR = 1.170, 95% confidence interval CI = 0.790-1.734, p = 0.434). Conclusion: This MR study, for the first time in Chinese and Japanese populations, found no significant association between smoking and AD.

Genetic variations in the bitter taste receptor gene TAS2R38 are related to cigarette smoking behavior in Han Chinese smokers.

BACKGROUND: Smoking behavior is influenced by multiple genes, including the bitter taste gene TAS2R38. It has been reported that the correlation between TAS2R38 and smoking behavior has ethnicity-based differences. However, the TAS2R38 status in Chinese smokers is still unclear. OBJECTIVE: This study aims to investigate the possible relationship between genetic variations in TAS2R38 (A49P, V262A and I296V) and smoking behaviors in the Han Chinese population. METHODS: The haplotype analyses were performed and smoking behavior questionnaire was completed by 1271 individuals. Genetic association analyses for smoking behavior were analyzed using chi-square test. Further, for investigating the molecular mechanism of TAS2R38 variants effect on smoking behavior, we conducted TAS2R38-PAV and TAS2R38-AVI expression plasmids and tested the cellular calcium assay by cigarette smoke compounds stimulus in HEK293. RESULTS: Significant associations of genetic variants within TAS2R38 were identified with smoking behavior. We found a higher PAV/PAV frequency than AVI/AVI in moderate and high nicotine dependence (FTND ≥ 4; X2 = 4.611, 1 df, p = 0.032) and strong cigarette smoke flavor intensity preference (X2 = 4.5383, 1 df, p = 0.033) in participants. Furthermore, in the in vitro cellular calcium assay, total particle matter (TPM), N-formylnornicotine and cotinine, existing in cigarette smoke, activated TAS2R38-PAV but not TAS2R38-AVI-transfected cells. CONCLUSION: Our data highlights that genetic variations in TAS2R38 are related to smoking behavior, especially nicotine dependence and cigarette smoke flavor intensity preference. Our findings may encourage further consideration of the taste process to identify individuals susceptible to nicotine dependence, particularly Han Chinese smokers.

Correction: Insects (Thrips hawaiiensis (Morgan)) change the stereochemical configuration of 1-phenylethanol emitted from tea (Camellia sinensis) flowers.

[This corrects the article DOI: 10.1039/C7RA03219F.].

Characterization of enzymes specifically producing chiral flavor compounds (R)- and (S)-1-phenylethanol from tea (Camellia sinensis) flowers.

1-Phenylethanol is a chiral flavor compound that has enantiomers, (R)- and (S)-1-phenylethanol, with different flavor properties. Given that isolating these enantiomers from plants is low yielding and costly, enzymatic synthesis presents an alternative approach. However, the genes/enzymes that specifically produce (R)- and (S)-1-phenylethanol in plants are unknown. To identify these enzymes in tea (Camellia sinensis) flowers, 21 short chain dehydrogenase (SDR) genes were isolated from tea flowers, cloned, and functionally characterized. Several recombinant SDRs in Escherichia coli exhibited activity for converting acetophenone to (S)-1-phenylethanol (CsSPESs, >99.0%), while only one SDR produced (R)-1-phenylethanol (CsRPES, 98.6%). A pair of homologue enzymes (CsSPES and CsRPES) showed a strong preference for NADPH cofactor, with optimal enzymatic reaction conditions of 45-55 °C and pH 8.0. Identification of the tea flower-derived gene responsible for specific synthesis of (R)- and (S)-1-phenylethanolsuggests enzymatic synthesis of enantiopure 1-phenylethanol is possible using a plant-derived gene.

Study of the biochemical formation pathway of aroma compound 1-phenylethanol in tea (Camellia sinensis (L.) O. Kuntze) flowers and other plants.

After tea leaves, tea (Camellia sinensis) flowers are becoming a second tea plant resource because they contain not only functional metabolites similar to those found in tea leaves, but also predominant amounts of functional metabolites that only occur in tea leaves in small amounts. 1-Phenylethanol (1PE) is a predominant aroma compound found in tea flowers. A 1PE synthase in tea flowers was isolated, functionally characterized, and shown to have the highest catalytic efficiency for the conversion of acetophenone (AP). To determine why 1PE accumulates more in tea flowers than other plants, we compared their 1PE contents and used a stable isotope labeling method to elucidate the 1PE biosynthetic route. Supplementation with [2H8]l-phenylalanine and [2H5]AP suggested that most plants containing the enzyme/gene catalyzed the conversion of AP to 1PE. Furthermore, the availability of AP derived from l-phenylalanine was responsible for the difference in 1PE accumulation between tea flowers and other plants.

Effect of Sling Exercise Training on Balance in Patients with Stroke: A Meta-Analysis.

OBJECTIVE: This study aims to evaluate the effect of sling exercise training (SET) on balance in patients with stroke. METHODS: PubMed, Cochrane Library, Ovid LWW, CBM, CNKI, WanFang, and VIP databases were searched for randomized controlled trials of the effect of SET on balance in patients with stroke. The study design and participants were subjected to metrological analysis. Berg balance Scale (BBS), Barthel index score (BI), and Fugl-Meyer Assessment (FMA) were used as independent parameters for evaluating balance function, activities of daily living(ADL) and motor function after stroke respectively, and were subjected to meta-analysis by RevMan5.3 software. RESULTS: Nine studies with 460 participants were analyzed. Results of meta-analysis showed that the SET treatment combined with conventional rehabilitation was superior to conventional rehabilitation treatments, with increased degrees of BBS (WMD = 3.81, 95% CI [0.15, 7.48], P = 0.04), BI (WMD = 12.98, 95% CI [8.39, 17.56], P < 0.00001), and FMA (SMD = 0.76, 95% CI [0.41, 1.11], P < 0.0001). CONCLUSION: Based on limited evidence from 9 trials, the SET treatment combined with conventional rehabilitation was superior to conventional rehabilitation treatments, with increased degrees of BBS, BI and FMA, So the SET treatment can improvement of balance function after stroke, but the interpretation of our findings is required to be made with caution due to limitations in included trials such as small sample sizes and the risk of bias. Therefore, more multi-center and large-sampled randomized controlled trials are needed to confirm its clinical applications.