Lactobacillus plantarum AR495 improves colonic transport hyperactivity in irritable bowel syndrome through tryptophan metabolism.

Lactobacillus plantarum AR495 is a widely used probiotic for the treatment of various digestive diseases, including irritable bowel syndrome (IBS). However, the specific mechanisms of L. plantarum AR495 in alleviating IBS remain unclear. Abnormal intestinal tryptophan metabolism can cause disordered immune responses, gastrointestinal peristalsis, digestion and sensation, which is closely related to IBS pathogenesis. The aim of this study is to explore the effects and mechanisms of L. plantarum AR495 in regulating tryptophan metabolism. Primarily, tryptophan and its related metabolites in patients with IBS and healthy people were analyzed, and an IBS rat model of acetic acid enema plus restraint stress was established to explore the alleviation pathway of L. plantarum AR495 in tryptophan metabolism. It was found that the 5-HT pathway was significantly changed, and the 5-HTP and 5-HT metabolites were significantly increased in the feces of patients with IBS, which were consistent with the results obtained for the IBS rat model. Maladjusted 5-HT could increase intestinal peristalsis and lead to an increase in the fecal water content and shapeless stool in rats. On the contrary, these two metabolites could be restored to normal levels via intragastric administration of L. plantarum AR495. Further study of the metabolic pathway showed that L. plantarum AR495 could effectively reduce the abundance of 5-HT by inhibiting the expression of enterochromaffin cells rather than promoting its decomposition. In addition, the results showed that L. plantarum AR495 did not affect the expression of SERT. To sum up, L. plantarum AR495 could restore the normal levels of 5-HT by inhibiting the abnormal proliferation of enterochromaffin cells and the excessive activation of TPH1 to inhibit the intestinal peristalsis in IBS. These findings provide insights for the use of probiotics in the treatment of IBS and other diarrheal diseases.

Investigating the Role of ß-Disodium Glycerophosphate and Urea in Promoting Growth of Streptococcus thermophilus from Omics-Integrated Genome-Scale Models.

This study investigates the impact of urea and ß-GP on the growth of Streptococcus thermophilus S-3, a bacterium commonly used in industrial fermentation processes. Through a series of growth experiments, transcriptome, metabolome, and omics-based analyses, the research demonstrates that both urea and ß-GP can enhance the biomass of S. thermophilus, with urea showing a more significant effect. The optimal urea concentration for growth was determined to be 3 g/L in M17 medium. The study also highlights the metabolic pathways influenced by urea and ß-GP, particularly the galactose metabolism pathway, which is crucial for cell growth when lactose is the substrate. The integration of omics data into the genome-scale metabolic model of S. thermophilus, iCH502, allowed for a more accurate prediction of metabolic fluxes and growth rates. The study concludes that urea can serve as a viable substitute for ß-GP in the cultivation of S. thermophilus, offering potential cost and efficiency benefits in industrial fermentation processes. The findings are supported by validation experiments with 11 additional strains of S. thermophilus, which showed increased biomass in UM17 medium.

Exploring the gut microbiome-Postoperative Cognitive Dysfunction connection: Mechanisms, clinical implications, and future directions.

Postoperative Cognitive Dysfunction (POCD) is a common yet poorly understood complication of surgery that can lead to long-term cognitive decline. The gut-brain axis, a bidirectional communication system between the central nervous system and the gut microbiota, plays a significant role in maintaining cognitive health. The potential for anesthetic agents and perioperative medications to modulate the gut microbiota and influence the trajectory of POCD suggests the need for a more integrated approach in perioperative care. Perioperative medications, including opioids and antibiotics, further compound these disruptions, leading to dysbiosis and consequent systemic and neuroinflammation implicated in cognitive impairment. Understanding how surgical interventions and associated treatments affect this relationship is crucial for developing strategies to reduce the incidence of POCD. Strategies to preserve and promote a healthy gut microbiome may mitigate the risk and severity of POCD. Future research should aim to clarify the mechanisms linking gut flora alterations to cognitive outcomes and explore targeted interventions, such as probiotic supplementation and microbiota-friendly prescription practices, to safeguard cognitive function postoperatively.

Inhibitory effects of black phosphorus nanosheets on tumor cell proliferation through downregulation of ADIPOQ and downstream signaling pathways.

Exposure to environmental pollutants, including nanomaterials, has a significant impact on tumor progression. The increased demand for black phosphorus nanosheets (BPNSs), driven by their exceptional properties, raises concerns about potential environmental contamination. Assessing their toxicity on tumor growth is essential. Herein, we employed a range of biological techniques, including cytotoxicity measurement, bioinformatics tools, proteomics, target gene overexpression, Western blot analysis, and apoptosis detection, to investigate the toxicity of BPNSs across A549, HepG-2, MCF-7, and Caco-2 cell lines. Our results demonstrated that BPNSs downregulated the expression of ADIPOQ and its associated downstream pathways, such as AMP-activated protein kinase (AMPK), nuclear factor erythroid 2-related factor 2 (Nrf2), and other unidentified pathways. These downregulated pathways ultimately led to mitochondria-dependent apoptosis. Notably, the specific downstream pathways involved varied depending on the type of tumors. These insightful findings not only confirm the consistent inhibitory effects of BPNSs across different tumor cells, but also elucidate the cytotoxicity mechanisms of BPNSs in different tumors, providing valuable information for their safe application and health risk assessment.

Understanding Ligilactobacillus salivarius from Probiotic Properties to Omics Technology: A Review.

Ligilactobacillus salivarius (basonym: Lactobacillus salivarius, L. salivarius) is a type of lactic acid bacteria (LAB) commonly found in the oropharyngeal-gastrointestinal tract (OGT). It has gained significant attention due to its probiotic and functional properties as well as its various health-promoting roles. L. salivarius strains exhibit strong resistance and adhesion in the OGT along with outstanding antioxidant and antimicrobial properties. Additionally, numerous L. salivarius strains have the ability to produce bacteriocins with antagonistic activity. These probiotic characteristics of L. salivarius indicate its remarkable potential in promoting favorable effects on human health. It has also been observed that L. salivarius has a positive effect on the composition of intestinal microbiota, thereby improving the metabolic profiling of intestinal microbiota, promoting a healthy and balanced internal environment. In recent years, multi-omics technologies such as genomics, transcriptomics, proteomics and metabolomics have been employed to gain a deeper understanding of the roles and mechanisms of L. salivarius associated with its functional properties. This review aims to provide an overview of the probiotic characteristics of L. salivarius, containing its specific interactions with the host microflora, as well as insights from omics studies.

Characterization of a Panel of Constitutive Promoters from Lactococcus cremoris for Fine-Tuning Gene Expression.

Lactococcus cremoris (homotypic synonym: Lactococcus lactis) is receiving increasing attention as a prominent vehicle for the delivery of live vaccines. This can hardly be achieved without developing tools for the genetic manipulation of L. cremoris, and the paucity of studies on L. cremoris endogenous promoters has attracted our attention. Here, we report the discovery and characterization of 29 candidate promoters identified from L. cremoris subsp. cremoris NZ9000 by RNA sequencing analysis. Furthermore, 18 possible constitutive promoters were obtained by RT-qPCR screening from these 29 candidate promoters. Then, these 18 promoters were cloned and characterized by a reporter gene, gusA, encoding ß-glucuronidase. Eventually, eight endogenous constitutive promoters of L. cremoris were obtained, which can be applied to genetic manipulation of lactic acid bacteria.

Nickel-Catalyzed Reductive Cross-Coupling of Propargylic Acetates with Chloro(vinyl)silanes: Access to Silylallenes.

Because of their various reactivities, propargyl acetates are refined chemical intermediates that are extensively applied in pharmaceutical synthesis. Currently, reactions between propargyl acetates and chlorosilanes may be the most effective method for synthesizing silylallenes. Nevertheless, owing to the adaptability and selectivity of substrates, transition metal catalysis is difficult to achieve. Herein, nickel-catalyzed reductive cross-coupling reactions between propargyl acetates and substituted vinyl chlorosilanes for the synthesis of tetrasubstituted silylallenes are described. Therein, metallic zinc is a crucial reductant that effectively enables two electrophilic reagents to selectively construct C(sp2)-Si bonds. Additionally, a Ni-catalyzed reductive mechanism involving a radical process is proposed on the basis of deuteration-labeled experiments.

Cobalt-Promoted Photoredox 1,2-Amidoamination of Alkenes with N-Sulfonamidopyridin-1-ium Salts and Free Amines.

A cobalt-promoted photoredox 1,2-amidoamination of alkenes with N-sulfonamidopyridin-1-ium salts and free amines for the synthesis of unsymmetrical vicinal diamines has been developed. The reaction handles N-(sulfonamido)pyridin-1-ium salts as the sulfonamidyl radical precursors and free amines as the nucleophilic terminating reagents to enable the formation of two new C(sp3)-N bonds in a single reaction step and offers a route to selectively producing unsymmetrical vicinal diamines with an exquisite selectivity and a good compatibility of functional groups.

Divergent [2 + n] Heteroannulation of ß-CF3-1,3-enynes with Alkyl Azides via Hydrogen Atom Transfer and Radical Substitution.

A copper-promoted divergent intermolecular [2 + n] heteroannulation of ß-CF3-1,3-enynes with alkyl azides via alkyl radical-driven HAT and radical substitution (C-C bond formation) to form four- to ten-membered saturated N-heterocycles is developed. This method enables the aryl-induced or kinetically controlled site selective functionalization of the remote C(sp3)-H bonds at positions 2, 3, 4, 5, 6, 7, or 8 toward the nitrogen atom through triplet nitrene formation, radical addition across the C═C bond, HAT and radical substitution cascades, and features a broad substrate scope, excellent site selectivity, and facile late-stage derivatization of bioactive molecules. Initial deuterium-labeling and control experiments shed light on the reaction mechanism via nitrene formation and HAT.

Genome-scale reconstruction of the metabolic network in Streptococcus thermophilus S-3 and assess urea metabolism.

BACKGROUND: Streptococcus thermophilus is an important strain widely used in dairy fermentation, with distinct urea metabolism characteristics compared to other lactic acid bacteria. The conversion of urea by S. thermophilus has been shown to affect the flavor and acidification characteristics of milk. Additionally, urea metabolism has been found to significantly increase the number of cells and reduce cell damage under acidic pH conditions, resulting in higher activity. However, the physiological role of urea metabolism in S. thermophilus has not been fully evaluated. A deep understanding of this metabolic feature is of great significance for its production and application. Genome-scale metabolic network models (GEMs) are effective tools for investigating the metabolic network of organisms using computational biology methods. Constructing an organism-specific GEM can assist us in comprehending its characteristic metabolism at a systemic level. RESULTS: In the present study, we reconstructed a high-quality GEM of S. thermophilus S-3 (iCH492), which contains 492 genes, 608 metabolites and 642 reactions. Growth phenotyping experiments were employed to validate the model both qualitatively and quantitatively, yielding satisfactory predictive accuracy (95.83%), sensitivity (93.33%) and specificity (100%). Subsequently, a systematic evaluation of urea metabolism in S. thermophilus was performed using iCH492. The results showed that urea metabolism reduces intracellular hydrogen ions and creates membrane potential by producing and transporting ammonium ions. This activation of glycolytic fluxes and ATP synthase produces more ATP for biomass synthesis. The regulation of fluxes of reactions involving NAD(P)H by urea metabolism improves redox balance. CONCLUSION: Model iCH492 represents the most comprehensive knowledge-base of S. thermophilus to date, serving as a potent tool. The evaluation of urea metabolism led to novel insights regarding the role of urease. © 2023 Society of Chemical Industry.

Software-based screening for efficient sgRNAs in Lactococcus lactis.

BACKGROUND: The two essential editing elements in the clustered regularly interspaced short palindromic repeats (CRISPR) editing system are promoter and single-guide RNA (sgRNA), the latter of which determines whether Cas protein can precisely target a specific location to edit the targeted gene. Therefore, the selection of sgRNA is crucial to the efficiency of the CRISPR editing system. Various online prediction tools for sgRNA are currently available. These tools can predict all possible sgRNAs of the targeted gene and rank sgRNAs according to certain scoring criteria according to the demands of the user. RESULTS: We designed sgRNAs for Lactococcus lactis NZ9000 LLNZ_RS02020 (ldh) and LLNZ_RS10925 (upp) individually using online prediction software - CRISPOR - and successfully constructed a series of knockout strains to allow comparison of the knockout efficiency of each sgRNA and analyze the differences between software predictions and actual experimental results. CONCLUSION: Our experimental results showed that the actual editing efficiency of the screened sgRNAs did not match the predicted results - a phenomenon that suggests that established findings from eukaryotic studies are not universally applicable to prokaryotes. Software prediction can still be used as a tool for the initial screening of sgRNAs before further selection of suitable sgRNAs through experimental experience. © 2023 Society of Chemical Industry.

Metal-Organic Gel Leading to Customized Magnetic-Coupling Engineering in Carbon Aerogels for Excellent Radar Stealth and Thermal Insulation Performances.

Metal-organic gel (MOG) derived composites are promising multi-functional materials due to their alterable composition, identifiable chemical homogeneity, tunable shape, and porous structure. Herein, stable metal-organic hydrogels are prepared by regulating the complexation effect, solution polarity and curing speed. Meanwhile, collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination. Subsequently, two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect. FeCo/nitrogen-doped carbon (NC) aerogel demonstrates an ultra-strong microwave absorption of - 85 dB at an ultra-low loading of 5%. After reducing the time taken by atom shifting, a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained, which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles. Furthermore, both aerogels show excellent thermal insulation property, and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology. The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels, which will enable the development and application of novel and lightweight stealth coatings.

Chemodivergent Synthesis of Benzothiadiazin-3-one 1-Oxides and Benzisothiazol-3-ones via Visible Light-Promoted Intramolecular N-S Bond Formation.

We reported a versatile protocol to chemodivergently construct significant heterocyclic scaffolds of benzothiadiazin-3-one 1-oxides and benzisothiazol-3-ones by visible light-promoted photocatalysis. This substrate-dependent chemoselective strategy enables N-(2-mercaptophenyl)-N'-substituted ureas through the N-S bond coupling/oxidation cascade to selectively produce benzothiadiazin-3-one 1-oxides; however, the transformation of 2-mercaptobenzamides only occurs via N-S bond coupling to access benzisothiazol-3-ones with moderate to good yields. This strategy features mild conditions, excellent chemoselectivity, and functional group compatibility, which has potential applications in organic and medicinal chemistry.

Electroreductive Carboxylation of Propargylic Acetates with CO2: Access to Tetrasubstituted 2,3-Allenoates.

An electroreductive carboxylation of propargylic alcohols with CO2 and then workup with TMSCHN2 to construct tetrasubstituted 2,3-allenoates is developed. This method allows the incorporation of an external ester group into the resulting allene system through electroreduction, carboxylation, and deacetoxylation cascades. Mechanistically, electricity on/off experiments and cyclic voltammetry analysis support the preferential generation of the CO2 radical anion or the 3-aryl propargylic acetate radical anion based on the electron nature of the aryl rings.

Identification of lncRNAs associated with uterine corpus endometrial cancer prognosis based on the competing endogenous RNA network.

Uterine Corpus Endometrial Carcinoma (UCEC) is one of the major malignant tumors of the female reproductive system. However, there are limitations in the currently available diagnostic approaches for UCEC. Long non-coding RNAs (lncRNAs) play important roles in regulating biological processes as competitive endogenous RNA (ceRNA) in tumors. To study the potential of lncRNAs as non-invasive diagnostic tumor markers, RNA-sequencing dataset of UCEC patients from The Cancer Genome Atlas was used to identify differentially expressed genes. A lncRNA-miRNA-mRNA ceRNA network was constructed by differentially expressed lncRNAs, miRNAs and miRNAs. Pathway enrichment and functional analysis for the mRNAs in the constructed ceRNA network provide the direction of future research for UCEC by demonstrating the most affected processes and pathways. Seven potential lncRNA biomarkers (C20orf56, LOC100144604, LOC100190940, LOC151534, LOC727677, FLJ35390, LOC158572) were validated in UCEC patients by quantitative real-time PCR. Notably, LOC100190940 and LOC158572 were identified as novel RNA molecules with unknown functions. Receiver operating characteristic (ROC) curve analysis demonstrated that the combined 7 lncRNAs had a high diagnostic value for UCEC patients with area under curve (AUC) of 0.941 (95% CI: 0.875-0.947). Our study highlights the potential of the validated 7 lncRNAs panel as diagnostic biomarkers in UCEC, providing new insights into the UCEC pathogenesis.

Cobalt-Promoted Electroreductive Cross-Coupling of Prop-2-yn-1-yl Acetates with Chloro(vinyl)silanes.

An electroreductive cross-coupling of prop-2-yn-1-yl acetates with chloro(vinyl)silanes for producing tetrasubstituted silylallenes is developed. The method enables the formation of a new C─Si bond through the cathodic reduction formation of the silyl radical, radical addition across the C≡C bond, the alkenyl anion intermediate formation, and deacetoxylation and represents a mild, practical route to the synthesis of silylallenes. Mechanistic studies reveal that CoCl2 acts as the mediator to promote the formation of the alkenyl anion intermediate via electron transfer.

Neuroprotective Effects of Human-Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cell Extracellular Vesicles in Ischemic Stroke Models.

BACKGROUND: Stroke represents the second leading cause of death and the primary cause of long-term disability in humans. The transplantation of mesenchymal stem cells (MSC) reportedly improves functional outcomes in animal models of cerebral ischemia. Here, we evaluate the neuroprotective potential of extracellular vesicles secreted from human-induced pluripotent stem cell-derived mesenchymal stem cells (hiPS-MSC-EV) using preclinical cell-based and animal-based models of ischemic strokes. METHODS: hiPS-MSC-EV were isolated using an ultrafiltration method. HT22 cells were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) injury for 2 h, followed by treatment with hiPS-MSC-EV (100 µg/mL). Male C57BL/6 mice were subjected to middle cerebral artery occlusion (MCAO) followed by an intravenous injection of hiPS-MSC-EV (100 µg) at three distinct time points. RESULTS: Our experimental approach revealed hiPS-MSC-EV promoted HT22 cell proliferation, reduced apoptosis, and altered cellular morphology following OGD/R. In addition, hiPS-MSC-EV reduced the volume of infarcts, improved spontaneous movement abilities, and enhanced angiogenesis by expressing the VEGF and CXCR4 proteins in the infarcted hemisphere of the MCAO-treated mouse model. CONCLUSION: Our findings provide evidence of the potential neuroprotective effects of hiPS-MSC-derived extracellular vesicles (hiPS-MSC-EVs) in both in vitro and in vivo mouse models of ischemic stroke. These results suggest that hiPS-MSC-EVs may play a role in neurorestoration and offer insights into potential cell-free strategies for addressing cerebral ischemia.

Identification of new reference genes for colony counting by reverse-transcription quantitative PCR in Bifidobacterium animalis.

Bifidobacterium animalis, one of the predominant bacteria in the intestines of humans and other mammals, is widely added to dairy products. We employed RNA sequencing to analyze gene expression variance on a genome-wide scale and found stable reference genes (RG) in B. animalis. A total of 1,665 genes were identified by analyzing the data from the transcriptome under 4 different conditions, and 13 probable candidate RG with variation coefficient values <0.1 were validated using reverse-transcription quantitative PCR (RT-qPCR). The amplification efficiency of candidate RG were ranging from 94.16% to 126.25%. We integrated the analysis results of BestKeeper, geNorm, NormFinder, and RefFinder algorithms and revealed that rplD and atpA comprehensive ranked 1.68 and 2.82, respectively, which were more stable than traditional RG. Compared with plate count (1.58 × 106 cfu/mL), the concentrations of B. animalis AR668 by RT-qPCR using rplD, atpA, and 16S rRNA as RG were 2.27 × 106, 2.24 × 106, and 6.66 × 106 cfu/mL, respectively, after 10 h of fermentation in fermented skim milk. It suggested that rplD and atpA as RG can be accurate for colony counting of B. animalis. Our study provides the foundation for more accurate analysis of colony counting by RT-qPCR of B. animalis in dairy foods.

Circulating microRNAs as diagnostic biomarkers for ischemic stroke: evidence from comprehensive analysis and real-world validation.

Ischemic stroke (IS) is the majority of strokes which remain the second leading cause of deaths in the last two decades. Circulating microRNAs (miRNAs) have been suggested as potential diagnostic and therapeutic tools for IS by previous studies analyzing their differential expression. However, inconclusive and controversial conclusions of these results have to be addressed. In this study, comprehensive analysis and real-world validation were performed to assess the associations between circulating miRNAs and IS. 29 studies with 112 miRNAs were extracted after manual selection and filtering, 12 differentially expressed miRNAs were obtained from our results of meta-analysis. These miRNAs were evaluated in 20 IS patients, compared to 20 healthy subjects. 4 miRNAs (hsa-let-7e-5p, hsa-miR-124-3p, hsa-miR-17-5p, hsa-miR-185-5p) exhibited the significant expression level in IS patient plasma samples. Pathway and biological process enrichment analysis for the target genes of the 4 validated miRNAs identified cellular senescence and neuroinflammation as key post-IS response pathways. The results of our analyses closely correlated with the pathogenesis and implicated pathways observed in IS subjects suggested by the literature, which may provide aid in the development of circulating diagnostic or therapeutic targets for IS patients.

Recent Advances in the Biological Responses to Nano-black Phosphorus: Understanding the Importance of Intrinsic Properties and Cell Types.

The production scalability and increasing demand for nano-black phosphorus materials (nano-BPs) inevitably lead to their environmental leakage, thereby raising the risk of human exposure through inhalation, ingestion, dermal, and even intravenous pathways. Consequently, a systematic evaluation of their potential impacts on human health is necessary. This Review outlines recent progress in the understanding of various biological responses to nano-BPs. Attention is particularly given to the inconsistent toxicological findings caused by a wide variation of nano-BPs' physicochemical properties, toxicological testing methods, and cell types examined in each study. Additionally, cellular uptake and intracellular trafficking, cell death modes, immunological effects, and other biologically relevant processes are discussed in detail, providing evidence for the potential health implications of nano-BPs. Finally, we address the remaining challenges related to the health risk evaluation of nano-BPs and propose a broader range of applications for these promising nanomaterials.