Electrostatically mediated layer-by-layer assembly of nitrogen-doped graphene/PDDA/gold nanoparticle composites for electrochemical detection of uric acid.

A layer-by-layer self-assembled nitrogen-doped graphene/PDDA/gold nanoparticle (NDG/PDDA/GNP) composite was described. Citrate-stabilizing gold nanoparticle colloids (GNPs) were electrostatically adsorbed onto NDG nanosheets using a cationic polyelectrolyte, polydiallyldimethylammonium (PDDA), as the linker, thereby creating a high-performance electrochemical interface. The morphology and chemical composition were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, infrared spectroscopy, and Raman spectroscopy. Analytical application was manifested by electrochemical sensing of uric acid (UA), a biomarker involved with a variety of clinical diseases. The prepared nanocomposite exhibited noticeable electroactivity to uric acid oxidation and can give effective peak separation with ascorbic acid and dopamine. Additionally, the nanocomposite practically averted from other potentially interferents including glucose, urea, and serotonin, thus allowing selective voltammetric detection of UA in the biological matrix. Under the optimal condition, peak currents measured by differential pulse voltammetry were proportional to UA concentrations in the range of 0.5~100 µM (R2 = 0.998), with the detection limit of 53 nM. The NDG/PDDA/GNP nanocomposite as presented herein holds potential for aiding the diagnosis of UA-associated diseases and should be a new opportunity for biochemical analysis and biosensing applications. Graphical abstract.

Profiling microRNA expression during multi-staged date palm (Phoenix dactylifera L.) fruit development.

MicroRNAs (miRNAs) play crucial roles in multiple stages of plant development and regulate gene expression at posttranscriptional and translational levels. In this study, we first identified 238 conserved miRNAs in date palm (Phoenix dactylifera) based on a high-quality genome assembly and defined 78 fruit-development-associated (FDA) miRNAs, whose expression profiles are variable at different fruit development stages. Using experimental data, we subsequently detected 276 novel P. dactylifera-specific FDA miRNAs and predicted their targets. We also revealed that FDA miRNAs function mainly in regulating genes involved in starch/sucrose metabolisms and other carbon metabolic pathways; among them, 221 FDA miRNAs exhibit negative correlation with their corresponding targets, which suggests their direct regulatory roles on mRNA targets. Our data define a comprehensive set of conserved and novel FDA miRNAs along with their expression profiles, which provide a basis for further experimentation in assigning discrete functions of these miRNAs in P. dactylifera fruit development.

Structure and antitumor and immunomodulatory activities of a water-soluble polysaccharide from Dimocarpus longan pulp.

A new water-soluble polysaccharide (longan polysaccharide 1 (LP1)) was extracted and successfully purified from Dimocarpus longan pulp via diethylaminoethyl (DEAE)-cellulose anion-exchange and Sephacryl S-300 HR gel chromatography. The chemical structure was determined using Infrared (IR), gas chromatography (GC) and nuclear magnetic resonance (NMR) analysis. The results indicated that the molecular weight of the sample was 1.1 × 10(5) Da. Monosaccharide composition analysis revealed that LP1 was composed of Glc, GalA, Ara and Gal in a molar ratio of 5.39:1.04:0.74:0.21. Structural analysis indicated that LP1 consisted of a backbone of → 4)-α-D-Glcp-(1 → 4)-α-D-GALPA-(1 → 4)-α-D-Glcp-(1 → 4)-ß-D-Glcp-(1 → units with poly saccharide side chains composed of → 2)-ß-D-Fruf-(1 → 2)-L-sorbose-(1 → attached to the O-6 position of the α-D-Glcp residues. In vitro experiments indicated that LP1 had significantly high antitumor activity against SKOV3 and HO8910 tumor cells, with inhibition percentages of 40% and 50%, respectively. In addition, LP1 significantly stimulated the production of the cytokine interferon-γ (IFN-γ), increased the activity of murine macrophages and enhanced B- and T-lymphocyte proliferation. The results of this study demonstrate that LP1 has potential applications as a natural antitumor agent with immunomodulatory activity.

Effectiveness of Mindfulness-Based Stress Reduction on Mental Health and Psychological Quality of Life among University Students: A GRADE-Assessed Systematic Review.

Background: Psychological distress is a progressive health problem that has been linked to decreased quality of life among university students. This meta-analysis reviews existing randomized controlled trials (RCTs) that have examined the effects of mindfulness-based stress reduction (MBSR) on the relief of psychosomatic stress-related outcomes and quality of life among university students. Methods: The PubMed, EMBASE, Web of Science, PsycINFO (formerly PsychLit), Ovid MEDLINE, ERIC, Scopus, Google Scholar, ProQuest, and Cochrane Library databases were searched in November 2023 to identify the RCTs for analysis. Data on pathology (anxiety, depression, and perceived stress), physical capacity (sleep quality and physical health), and well-being (mindfulness, self-kindness, social function, and subjective well-being) were analyzed. Results: Of the 276 articles retrieved, 29 met the inclusion criteria. Compared with control therapies, the pooled results suggested that MBSR had significant effects, reducing anxiety (SMD = -0.29; 95% CI: -0.49 to -0.09), depression (SMD = -0.32; 95% CI: -0.62 to -0.02), and perceived stress (SMD = -0.41; 95% CI: -0.60 to -0.29) and improving mindfulness (SMD = 0.34; 95% CI: 0.08 to 0.59), self-kindness (SMD = 0.57; 95% CI: 0.30 to 1.12), and physical health (SMD = -0.59; 95% CI: -1.14 to -0.04). No significant differences were observed in sleep quality (SMD = -0.20; 95% CI: -0.06 to 0.20), social function (SMD = -0.71; 95% CI: -2.40 to 0.97), or subjective well-being (SMD = 0.07; 95% CI: -0.18 to 0.32). The quality of the evidence regarding sleep quality and physical health outcomes was low. Conclusions: MBSR therapy appears to be potentially useful in relieving functional emotional disorders. However, additional evidence-based large-sample trials are required to definitively determine the forms of mindfulness-based therapy that may be effective in this context and ensure that the benefits obtained are ongoing. Future studies should investigate more personalized approaches involving interventions that are tailored to various barriers and students' clinical characteristics. To optimize the effects of such interventions, they should be developed and evaluated using various designs such as the multiphase optimization strategy, which allows for the identification and tailoring of the most valuable intervention components.

Seasonally variable intestinal metagenomes of the red palm weevil (Rhynchophorus ferrugineus).

The intestinal microbes residing in the red palm weevil (RPW, Rhynchophorus ferrugineus) larva consume tender interior fibrous tissues of date palm trunks. The understanding of such microbiota at molecular level provides vital clues for the biological control of this devastating pest. Using pyrosequencing and shotgun strategy, we first study taxonomic profiles of the microbiota sampled at different months (March, July and November), and then confirm the impact of high-temperature stress on the microbial populations based on data from 16S rRNA amplicons using both field and laboratory samples. We further identify Klebsiella pneumoniae in November and Lactococcus lactis in July as the dominant species of the microbiota. We find that the RPW gut microbiota degrades polysaccharides and sucrose with hydrolases and that different active bacterial species in November and July are responsible for the symbiotic relationship between the microbiota and the host. Our results provide vital information for pest control and cellulolytic bacterial species characterization.

In-situ facile preparation of highly efficient copper/nickel bimetallic nanocatalyst on chemically grafted carbon nanotubes for nonenzymatic sensing of glucose.

Measuring glucose in a convenient and economical manner is crucial for diabetes diagnostics and surveillance. Ongoing efforts are devoted to nonenzymatic sensors using functional nanomaterials. Drawbacks due to costly and cumbersome process, however, hamper the practicality. Here, we report the facile preparation of Cu/Ni bimetallic nanocatalyst toward glucose electrooxidation. Carboxylated multi-walled carbon nanotubes were chemically grafted onto indium tin oxide glass via silanization reaction and amide coupling reaction, providing distinct nucleation sites for Cu/Ni bimetallic electrocatalyst prepared by in-situ succinct electrodeposition, which synthetically created a three-dimensional electron transfer network. The surface morphology and chemical constituents were characterized by scanning electron microscopy, transmission electron microscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, infrared spectroscopy and atomic force microscopy. The prepared electrocatalyst displayed ultrahigh electrochemical activity; the catalytic current density for glucose oxidation was found to be over 6.7 mA mM-1 cm-2. The linear response spanned three orders of magnitude of glucose concentration ranging from 1 µM to 1 mM. Analytical parameters such as accuracy, reproducibility, specificity and stability have also been validated. Importantly, we reveal that Ni plays a dominant role over Cu in electrocatalytic oxidation of glucose, thus bettering our understanding and strategy for nonenzymatic glucose sensor design. Advantages of the glucose sensor presented include easy bulk preparation, low cost, and ready-to-use.

Genome sequence of the date palm Phoenix dactylifera L.

Date palm (Phoenix dactylifera L.) is a cultivated woody plant species with agricultural and economic importance. Here we report a genome assembly for an elite variety (Khalas), which is 605.4 Mb in size and covers >90% of the genome (~671 Mb) and >96% of its genes (~41,660 genes). Genomic sequence analysis demonstrates that P. dactylifera experienced a clear genome-wide duplication after either ancient whole genome duplications or massive segmental duplications. Genetic diversity analysis indicates that its stress resistance and sugar metabolism-related genes tend to be enriched in the chromosomal regions where the density of single-nucleotide polymorphisms is relatively low. Using transcriptomic data, we also illustrate the date palm's unique sugar metabolism that underlies fruit development and ripening. Our large-scale genomic and transcriptomic data pave the way for further genomic studies not only on P. dactylifera but also other Arecaceae plants.