A review on fermented vegetables: Microbial community and potential upgrading strategy via inoculated fermentation.

Fermentation is a traditional method utilized for vegetable preservation, with microorganisms playing a crucial role in the process. Nowadays, traditional spontaneous fermentation methods are widely employed, which excessively depend on the microorganisms attached to the surface of raw materials, resulting in great difficulties in ideal control over the fermentation process. To achieve standardized production and improve product quality, it is essential to promote inoculated fermentation. In this way, starter cultures can dominate the fermentation processes successfully. Unfortunately, inoculated fermentation has not been thoroughly studied and applied. Therefore, this paper provides a systematic review of the potential upgrading strategy of vegetable fermentation technology. First, we disclose the microbial community structures and succession rules in some typical spontaneously fermented vegetables to comprehend the microbial fermentation processes well. Then, internal and external factors affecting microorganisms are explored to provide references for the selection of fermented materials and conditions. Besides, we widely summarize the potential starter candidates with various characteristics isolated from spontaneously fermented products. Subsequently, we exhibited the inoculated fermentation strategies with those isolations. To optimize the product quality, not only lactic acid bacteria that lead the fermentation, but also yeasts that contribute to aroma formation should be combined for inoculation. The inoculation order of the starter cultures also affects the microbial fermentation. It is equally important to choose a proper processing method to guarantee the activity and convenience of starter cultures. Only in this way can we achieve the transition from traditional spontaneous fermentation to modern inoculated fermentation.

Function and dynamics of the intrinsically disordered carboxyl terminus of ß2 adrenergic receptor.

Advances in structural biology have provided important mechanistic insights into signaling by the transmembrane core of G-protein coupled receptors (GPCRs); however, much less is known about intrinsically disordered regions such as the carboxyl terminus (CT), which is highly flexible and not visible in GPCR structures. The ß2 adrenergic receptor's (ß2AR) 71 amino acid CT is a substrate for GPCR kinases and binds ß-arrestins to regulate signaling. Here we show that the ß2AR CT directly inhibits basal and agonist-stimulated signaling in cell lines lacking ß-arrestins. Combining single-molecule fluorescence resonance energy transfer (FRET), NMR spectroscopy, and molecular dynamics simulations, we reveal that the negatively charged ß2AR-CT serves as an autoinhibitory factor via interacting with the positively charged cytoplasmic surface of the receptor to limit access to G-proteins. The stability of this interaction is influenced by agonists and allosteric modulators, emphasizing that the CT plays important role in allosterically regulating GPCR activation.

Thymopentin (TP-5) prevents lipopolysaccharide-induced neuroinflammation and dopaminergic neuron injury by inhibiting the NF-κB/NLRP3 signaling pathway.

Neuroinflammation plays a pivotal role in neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis and stroke, and is accompanied by excessive release of inflammatory cytokines and mediators by activated microglia. Microglial inflammatory response inhibition may be an effective strategy for preventing inflammatory disorders. However, the reciprocal connections between the central nervous system (CNS) and immune system have not been elucidated. Thus far, these links have been proven to mainly involve immuno- and neuropeptides. The pentapeptide thymopentin (TP-5) exerts a significant immunomodulatory effect; however, its antineuroinflammatory effects and underlying mechanism are still unclear. In this study, lipopolysaccharide (LPS) was used to establish an inflammation model, and the therapeutic effect of TP-5 was evaluated. Behavioral tests showed that TP-5 treatment could improve the performance of LPS-treated mice in the open field and pole test, but not hanging wire test. TP-5 also attenuated neuronal lesions in the brains of LPS-treated mice. TP-5 reduced cytotoxicity and morphological changes in activated microglia. Label-free quantitative analysis indicated that the expression of multiple proteins and the activation of associated signaling pathways were altered by TP-5. Moreover, TP-5 could inhibit LPS-induced neuroinflammation in the brain and BV2 microglia and the expression of major genes in the NF-κB/NLRP3 signaling pathway. Additionally, tyrosine hydroxylase (TH) expression downregulation was rescued in the LPS + TP-5 group compared with the LPS group. We conclude that TP-5 exerts neuroprotection by alleviating LPS-induced inflammatory damage and dopaminergic neurodegeneration. The protective effect of TP-5 may involve the NF-κB/NLRP3 signaling pathway.

Development of an HPLC-PDA Method for the Determination of Capsanthin, Zeaxanthin, Lutein, ß-Cryptoxanthin and ß-Carotene Simultaneously in Chili Peppers and Products.

For the better standardization and widespread application of the determination method of carotenoids in both chili peppers and their products, this work reports for the first time the simultaneous determination of five main carotenoids, including capsanthin, zeaxanthin, lutein, ß-cryptoxanthin and ß-carotene in chili peppers and their products, with optimized extraction and the high-performance liquid chromatography (HPLC) method. All parameters in the methodological evaluation were found to be in good stability, recovery and accuracy compliance with the reference values; the R coefficients for the calibration curves were more than 0.998; and the LODs and LOQs varied from 0.020 to 0.063 and from 0.067 to 0.209 mg/L, respectively. The characterization of five carotenoids in chili peppers and their products passed all the required validation criteria. The method was applied in the determination of carotenoids in nine fresh chili peppers and seven chili pepper products.

General Strategy To Improve the Photon Budget of Thiol-Conjugated Cyanine Dyes.

Maleimide-cysteine chemistry has been a routine practice for the site-specific labeling of fluorophores to proteins since the 1950s. This approach, however, cannot bring out the best photon budget of fluorophores. Here, we systematically measured the Cyanine3/5 dye conjugates via maleimide-thiol and amide linkages by counting the total emitted photons at the single-molecule level. While brightness and signal-to-noise ratios do not change significantly, dyes with thioether linkages exhibit more severe photobleaching than amide linkers. We then screened modern arylation-type bioconjugation strategies to alleviate this damage. Labeling thiols with phenyloxadiazole (POD) methyl sulfone, p-chloronitrobenzene, and fluorobenzene probes gave rise to electron-deficient aryl thioethers, effectively increasing the total emitted photons by 1.5-3 fold. Among the linkers, POD maintains labeling efficiency and specificity that are comparable to maleimide. Such an increase has proved to be universal among bulk and single-molecule assays, with or without triplet-state quenchers and oxygen scavengers, and on conformationally unrestricted or restricted cyanines. We demonstrated that cyanine-POD conjugates are general and superior fluorophores for thiol labeling in single-molecule FRET measurements of biomolecular conformational dynamics and in two-color STED nanoscopy using site-selectively labeled nanobodies. This work sheds light on the photobleaching mechanism of cyanines under single-molecule imaging while highlighting the interplay between the protein microenvironment, bioconjugation chemistry, and fluorophore photochemistry.

Co-Application of 1-MCP and Laser Microporous Plastic Bag Packaging Maintains Postharvest Quality and Extends the Shelf-Life of Honey Peach Fruit.

Honey peach (Prunus persica L.) is highly nutritious; it is an excellent source of sugars, proteins, amino acids, vitamins, and mineral elements. However, it is a perishable climacteric fruit that is difficult to preserve. In this study, "Feicheng" honey peach fruit was used as a test material to investigate the synergistic preservation effect of 1-methylcyclopropene (1-MCP) and laser microporous film (LMF). The peach fruits were fumigated for 24 h with 2 µL L-1 1-MCP, then packed in LMF. In comparison with the control treatment, 1-MCP + LMF treatment markedly decreased the respiration rate, weight loss, and rot rate of peach fruits. Moreover, the combination of 1-MCP and LMF suppressed the increase in soluble solids (SS) and reducing sugars (RS), as well as the decrease in titratable acid (TA) and ascorbic acid (AsA). The combined application also maintained a high protopectin content and low soluble pectin content; it reduced the accumulation of superoxide anions (O2-) and hydrogen peroxide (H2O2). Except in a few samples, the catalase (CAT) and ascorbate peroxidase (APX) activities were higher when treated by 1-MCP + LMF. Conversely, the phenylalanine deaminase (PAL), peroxidase (POD), lipase, lipoxygenase (LOX), polygalacturonase (PG), ß-glucosidase, and cellulase (Cx) activities were lower than in the control. Furthermore, 1-MCP + LMF treatment reduced the relative abundances of dominant pathogenic fungi (e.g., Streptomyces, Stachybotrys, and Issa sp.). The combined treatment improved the relative abundances of antagonistic fungi (e.g., Aureobasidium and Holtermanniella). The results indicated that the co-application of 1-MCP and LMF markedly reduced weight loss and spoilage, delayed the decline of nutritional quality, and inhibited the physiological and biochemical metabolic activities of peach during storage. These changes extended its shelf-life to 28 days at 5 °C. The results provide a reference for the commercial application of this technology.

Mechanisms of distinctive mismatch tolerance between Rad51 and Dmc1 in homologous recombination.

Homologous recombination (HR) is a primary DNA double-strand breaks (DSBs) repair mechanism. The recombinases Rad51 and Dmc1 are highly conserved in the RecA family; Rad51 is mainly responsible for DNA repair in somatic cells during mitosis while Dmc1 only works during meiosis in germ cells. This spatiotemporal difference is probably due to their distinctive mismatch tolerance during HR: Rad51 does not permit HR in the presence of mismatches, whereas Dmc1 can tolerate certain mismatches. Here, the cryo-EM structures of Rad51-DNA and Dmc1-DNA complexes revealed that the major conformational differences between these two proteins are located in their Loop2 regions, which contain invading single-stranded DNA (ssDNA) binding residues and double-stranded DNA (dsDNA) complementary strand binding residues, stabilizing ssDNA and dsDNA in presynaptic and postsynaptic complexes, respectively. By combining molecular dynamic simulation and single-molecule FRET assays, we identified that V273 and D274 in the Loop2 region of human RAD51 (hRAD51), corresponding to P274 and G275 of human DMC1 (hDMC1), are the key residues regulating mismatch tolerance during strand exchange in HR. This HR accuracy control mechanism provides mechanistic insights into the specific roles of Rad51 and Dmc1 in DNA double-strand break repair and may shed light on the regulatory mechanism of genetic recombination in mitosis and meiosis.

A novel non-enzymatic glucose electrochemical sensor with high sensitivity and selectivity based on CdIn2O4nanoparticles on 3D Ni foam substrate.

Due to the poor conductivity of Fe based, Cu based and Co based electrode materials commonly used in the electrochemical detection of glucose, and the uneven stirring and poor conductivity of the traditional preparation method based on glassy carbon electrode. In order to solve the above problems, in this work, CdIn2O4with high electrical conductivity was directly grown on three-dimensional (3D) Ni foam to prepare electrode materials for non-enzymatic glucose sensors. CdIn2O4nanoparticles is prepared from cadmium acetate and indium nitrate hydrate in benzyl alcohol by non-aqueous sol-gel method. The electrocatalytic oxidation performances of CdIn2O4electrode material for non-enzymatic glucose are studied. The results show that the proposed CdIn2O4electrode material has good electrochemical properties and sensing performance for glucose detection. The electrochemical response of CdIn2O4electrode material to glucose is recorded that calibration plot for glucose concentrations ranging from 1.0µM to 1.0 mM (R2 = 0.99), a limit detection of 0.08µM, an excellent sensitivity of 3.2925 mA.mM-1.cm-2, a rapid response time of 1.58 s, a good selectivity and a good long-term stability. These demonstrate the significant potential of CdIn2O4electrode material based on 3D Ni foam as non-enzymatic glucose sensors, which makes it possible to use it as a practical glucose detector. This work could introduce a new concept of nanoparticles modified electrode material grown directly on 3D Ni foam, thus a simple and reliable electrochemical glucose sensor platform is realized. This study was completed in 2019 in the school of materials and energy, Yunnan University.

SIRT1 Deacetylates TET2 and Promotes Its Ubiquitination Degradation to Achieve Neuroprotection Against Parkinson's Disease.

The epigenetic modifications, such as DNA methylation and histone acetylation, play a critical role in the pathogenesis of Parkinson's disease (PD). However, the relationship between DNA methylation and histone acetylation in PD is not fully understood. Previous studies have shown that patients with PD exhibit an epigenetic and transcriptional upregulation of Ten-Eleven Translocation 2 (TET2), a member of the DNA hydroxylases family. Silence information regulator 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylase, also plays a critical role in PD development and might be a potential target for PD therapy. Our previous data indicated that demethylation in the Cyclin-dependent kinase inhibitor 2A (CDKN2A) promoter by the TET2 directly activated its expression, then promoted the cell cycle arrest and cell death induced by 1-methyl-4-phenyl-pyridinium ion (MPP+). In this study, we found that the enzyme activity of SIRT1 is negatively correlated with the protein level of TET2. In addition, the deacetylation of TET2 induced by SIRT1 promotes TET2 degradation via the ubiquitin-proteasome pathway. Furthermore, the activation of endogenous SIRT1 by resveratrol (RV) leads to CDKN2A DNA hypermethylation due to the decreased TET2 protein levels, which relieves the inhibitory effect on CDK4 and upregulation of pRb, allowing cell proliferation and growth. Similar effects are observed for the inhibition of endogenous TET2 enzyme activity with TET2 inhibitor. Together, we discover a new mechanism by which the SIRT1-TET2-CDKN2A pathway is involved in the pathogenesis of PD, which may provide a potential target for PD treatment.

Untargeted and Targeted Metabolomics Profiling of Muscle Reveals Enhanced Meat Quality in Artificial Pasture Grazing Tan Lambs via Rescheduling the Rumen Bacterial Community.

Tan is a local fat-tail sheep that is famous for its great eating quality but with little attention to its meat metabolome. The aim of this study was to investigate Tan-lamb meat metabolome as well as the key rumen bacteria related to the beneficial compound deposition in the muscle using untargeted and targeted metabolomics under different feeding regimes: indoor feeding (F), artificial pasture grazing with indoor feeding (GF), and pure artificial pasture grazing (G). The untargeted metabolome was detected by ultraperformance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. Ruminal bacterial communities were detected by 16S rRNA sequencing. Using untargeted metabolomics, the main three altered metabolic pathways in the lamb, including amino acid, lipid, and nucleotide metabolisms, were found in the G group compared to the GF and F groups. Increased N-acetyl-l-aspartic acid, N-acetylaspartylglutamate, acetylcarnitine, and l-carnitine, but decreased carnosine and creatinine, were the main newly found G group-associated metabolites, which might contribute to the improved lamb meat functional quality. Compared to the F group, the G group feeding increased the contents of sweet amino acids (e.g., glycine, alanine, serine, and threonine) and umami amino acids (e.g., glutamic acid and aspartic acid) in the muscle, and G and GF groups increased the level of meat polyunsaturated fatty acid (PUFA), especially the concentration of n3 PUFA, and reduced n6/n3 in the muscle by targeted metabolomics. The abundance of ruminal Moryella was decreased, and Schwartzia and Anaeroplasma were increased in the G group, which were both strongly correlated with the n3 PUFA and other functional compounds in the muscle of lambs. In conclusion, artificial pasture grazing modified the meat amino acid and fatty acid composition as well as the related biological pathways through rescheduling the rumen bacterial community, which would be a better selection for production of healthier lamb meat products.

Maternal Folic Acid Supplementation Differently Affects the Small Intestinal Phenotype and Gene Expression of Newborn Lambs from Differing Litter Sizes.

The purpose of this study was to investigate the effect of maternal dietary folic acid (FA) supplementation during gestation on small intestinal development of newborn lambs of different litter sizes, focusing on the intestinal morphology and development-, apoptosis- and digestion-related genes expression. One hundred and twenty Hu ewes (Ovis aries) were inseminated and randomly allotted to three groups. One group received a control diet [without FA supplementation, control (CON)] and the other two groups received control diets supplemented with different amount of FA [16 or 32 mg FA per kg dry matter (DM), i.e., F16 and F32] during pregnancy. After lambing, according to the dietary FA levels and litter size (twins, TW; triplets, TR), the neonatal lambs were divided into 6 (TW-CON, TW-F16, TW-F32, TR-CON, TR-F16, TR-F32) treatment groups. The results showed that the ratio of small intestinal weight to live body weight and the thickness of the intestinal muscle layer in the offspring was enhanced significantly with increasing maternal FA supplementation (p < 0.05). Meanwhile, the expression levels of insulin-like growth factor I (IGF-I), B-cell lymphoma-2 (BCL-2) and sodium/glucose co-transporter-1 (SGLT1) in the small intestines of the newborn lambs were increased, while the opposite was true for Bcl2-associated × (BAX) in response to FA supplementation (p < 0.05). Moreover, the small intestinal weights of twins were significantly higher than those of triplets (p < 0.01), and the expression levels of IGF-I (p < 0.05), sucrase-isomaltase (SI) (p < 0.05) and solute carrier family 2 member 5 (SLC2A5) (p < 0.01) were significantly lower than those in triplets. These findings suggest that maternal FA supplementation could improve the offspring's small intestinal phenotype and the expression of development-, apoptosis- and digestion-related genes, so it could promote the small intestinal development of newborn lambs. Furthermore, the small intestine phenotypic development of twins was generally better than that of triplets, while the expression levels of the above genes of twins were lower than those of triplets.

Phase separation at the nanoscale quantified by dcFCCS.

Liquid-liquid phase separation, driven by multivalent macromolecular interactions, causes formation of membraneless compartments, which are biomolecular condensates containing concentrated macromolecules. These condensates are essential in diverse cellular processes. Formation and dynamics of micrometer-scale phase-separated condensates are examined routinely. However, limited by commonly used methods which cannot capture small-sized free-diffusing condensates, the transition process from miscible individual molecules to micrometer-scale condensates is mostly unknown. Herein, with a dual-color fluorescence cross-correlation spectroscopy (dcFCCS) method, we captured formation of nanoscale condensates beyond the detection limit of conventional fluorescence microscopy. In addition, dcFCCS is able to quantify size and growth rate of condensates as well as molecular stoichiometry and binding affinity of client molecules within condensates. The critical concentration to form nanoscale condensates, identified by our experimental measurements and Monte Carlo simulations, is at least several fold lower than the detection limit of conventional fluorescence microscopy. Our results emphasize that, in addition to micrometer-scale condensates, nanoscale condensates are likely to play important roles in various cellular processes and dcFCCS is a simple and powerful quantitative tool to examine them in detail.

Target search and recognition mechanisms of glycosylase AlkD revealed by scanning FRET-FCS and Markov state models.

DNA glycosylase is responsible for repairing DNA damage to maintain the genome stability and integrity. However, how glycosylase can efficiently and accurately recognize DNA lesions across the enormous DNA genome remains elusive. It has been hypothesized that glycosylase translocates along the DNA by alternating between a fast but low-accuracy diffusion mode and a slow but high-accuracy mode when searching for DNA lesions. However, the slow mode has not been successfully characterized due to the limitation in the spatial and temporal resolutions of current experimental techniques. Using a newly developed scanning fluorescence resonance energy transfer (FRET)-fluorescence correlation spectroscopy (FCS) platform, we were able to observe both slow and fast modes of glycosylase AlkD translocating on double-stranded DNA (dsDNA), reaching the temporal resolution of microsecond and spatial resolution of subnanometer. The underlying molecular mechanism of the slow mode was further elucidated by Markov state model built from extensive all-atom molecular dynamics simulations. We found that in the slow mode, AlkD follows an asymmetric diffusion pathway, i.e., rotation followed by translation. Furthermore, the essential role of Y27 in AlkD diffusion dynamics was identified both experimentally and computationally. Our results provided mechanistic insights on how conformational dynamics of AlkD-dsDNA complex coordinate different diffusion modes to accomplish the search for DNA lesions with high efficiency and accuracy. We anticipate that the mechanism adopted by AlkD to search for DNA lesions could be a general one utilized by other glycosylases and DNA binding proteins.

Molecular mechanism of networking among DegP, Skp and SurA in periplasm for biogenesis of outer membrane proteins.

The biogenesis of outer membrane proteins (OMPs) is an extremely challenging process. In the periplasm of Escherichia coli, a group of quality control factors work together to exercise the safe-guard and quality control of OMPs. DegP, Skp and SurA are the three most prominent ones. Although extensive investigations have been carried out, the molecular mechanism regarding the networking among these proteins remains mostly mysterious. Our group has previously studied the molecular interactions of OMPs with SurA and Skp, using single-molecule detection (SMD). In this work, again using SMD, we studied how OmpC, a representative of OMPs, interacts with DegP, Skp and SurA collectively. Several important discoveries were made. The self-oligomerization of DegP to form hexamer occurs over hundred micromolars. When OmpC is in a monomer state at a low concentration, the OmpC·DegP6 and OmpC·DegP24 complexes form when the DegP concentration is around sub-micromolars and a hundred micromolars, respectively. High OmpC concentration promotes the binding affinity of DegP to OmpC by ∼100 folds. Skp and SurA behave differently when they interact synergistically with DegP in the presence of substrate. DegP can degrade SurA-protected OmpC, but Skp-protected OmpC forms the ternary complex OmpC·(Skp3)n·DegP6 (n = 1,2) to resist the DegP-mediated degradation. Combined with previous results, we were able to depict a comprehensive picture regarding the molecular mechanism of the networking among DegP, Skp and SurA in the periplasm for the OMPs biogenesis under physiological and stressed conditions.

Identification of novel biomarkers in ischemic stroke: a genome-wide integrated analysis.

BACKGROUND: Ischemic Stroke (IS) is the most common neurological emergency disease and has become the second most frequent cause of death after coronary artery disease in 2015. Owing to its high fatality rate and narrow therapeutic time window, early identification and prevention of potential stroke is becoming increasingly important. METHODS: We used meta-analysis and bioinformatics mining to explore disease-related pathways and regulatory networks after combining messengerRNA (mRNA) and miRNA expression analyses. The purpose of our study was to screen for candidate target genes and microRNA(miRNA) for early diagnosis of potential stroke. RESULTS: Five datasets were collected from the Gene Expression Omnibus (GEO) database by systematical retrieval, which contained three mRNA datasets (102 peripheral blood samples in total) and two miRNA dataset (59 peripheral blood samples). Approximately 221 different expression(DE) mRNAs (155 upregulated and 66 downregulated mRNAs) and 185 DE miRNAs were obtained using the metaDE package and GEO2R tools. Further functional enrichments of DE-mRNA, DE-miRNA and protein-protein interaction (PPI) were performed and visualized using Cytoscape. CONCLUSION: Our study identified six core mRNAs and two regulated miRNAs in the pathogenesis of stroke, and we elaborated the intrinsic role of systemic lupus erythematosus (SLE) and atypical infections in stroke, which may aid in the development of precision medicine for treating ischemic stroke. However, the role of these novel biomarkers and the underlying molecular mechanisms in IS require further fundamental experiments and further clinical evidence.

A novel and sensitive ratiometric fluorescence assay for carbendazim based on N-doped carbon quantum dots and gold nanocluster nanohybrid.

A novel fluorescence "turn on" ratiometric fluorescent sensor was employed to determine carbendazim. The sensing process was achieved through the strong fluorescence resonance energy transfer (FRET) between nitrogen doped carbon quantum dots (N-CQDs) and gold nanocluster (AuNCs). The photoluminescence intensity of N-CQDs can be deactivated by AuNCs through FRET effect and recovered by the addition of carbendazim. The ratiometric detection of carbendazim is achieved by recording the photoluminescence and second-order Rayleigh scattering (SRS) signal of N-CQDs/AuNCs system. With the introduction of carbendazim to the sensing platform resulted in the photoluminescence and SRS signal of N-CQDS/AuNCs enhancing. UV-vis absorption, Zeta potential and fluorescence lifetime analyses indicate that the fluorescence turn on process can be attributed to the aggregation of AuNCs breaks the FRET process and increases SRS intensity. N-CQDs/AuNCs probe present a good sensitivity and selectivity for carbendazim detection, with two linear response ranges (1-100 µM, 150-1000 µM), low detection limit of 0.83 µM and 37.25 µM. Furthermore, real sample analyses indicate that the as-presented sensor has potentials in carbendazim determination in real sample analyses.

LXW7 attenuates inflammation via suppressing Akt/nuclear factor kappa B and mitogen-activated protein kinases signaling pathways in lipopolysaccharide-stimulated BV2 microglial cells.

Microglia activation is closely linked to ischemia, various chronic neurodegenerative diseases (e.g., Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis), and many other central nervous system diseases. Accumulating evidence suggests that depressing the microglial inflammatory response could be an effective treatment for inflammatory disorders. The integrin αvß3 inhibitor LXW7 has a neuroprotective effect; however, its anti-inflammatory effects and underlying mechanism remain unclear. Thus, we examined whether LXW7 would inhibit inflammatory cytokines and mediators, and we evaluated the potential mechanisms of its neuroprotective effects. Nitrite analysis revealed LXW7 reduced the nitric oxide (NO) level. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) suggested that LXW7 suppressed the expression of proinflammatory genes for tumor necrosis factor-alpha (TNF-α), interleukin 1-beta (IL-1ß), inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and anti-inflammatory gene interleukin 10 (IL-10) at the messenger ribonucleic acid level. Enzyme-linked immunosorbent assay results demonstrated that LXW7 treatment reduced the expression of prostaglandin E2 (PGE2), TNF-α, IL-1ß and IL-10 at the protein level. Western blotting was conducted to confirm the upregulation of inflammatory factors, including iNOS and COX-2 at the protein level. LXW7 inhibited major genes in the Akt/NF-κB and c-Jun NH2-terminal kinase/ mitogen-activated protein kinases (JNK/MAPK) signaling pathways. Immunofluorescence revealed that LXW7 inhibited the nuclear translocation of nuclear factor kappa B (NF-κB). Thus, LXW7 effectively alleviated LPS-induced inflammatory damage and had neuroprotective effects. The anti-inflammatory effects of LXW7 may be associated with the inhibition of microglial activation via Akt/NF-κB and JNK/MAPK signaling pathways by blocking integrin αvß3 receptor. The present study's findings suggest that LXW7 has a substantial therapeutic potential for treating inflammatory and neurodegenerative diseases.

Conformational Dynamics and Cleavage Sites of Cas12a Are Modulated by Complementarity between crRNA and DNA.

Cas12a is an RNA-guided endonuclease, which displays great potentials and several advantages over the well-known Cas9 in genome editing and engineering. Here, we established a quantitative kinetic scheme to describe the conformational dynamics of Cas12a/crRNA/dsDNA ternary complexes. The highly dynamic nature of Cas12a complexes, including their reversible formation, disassembly, and transition between different conformational states, is likely to be one of the key aspects contributing to their high specificity. The non-target strand is cleaved when its cleavage sites are released from DNA duplex after DNase activation of Cas12a. Cleaved non-target strand stabilizes target strand pre-cleavage states to permit subsequent cleavage and to ensure two DNA strands cleaved in a well-defined order. The extent of complementarity between crRNA and DNA modulates the relative stabilities of target strand pre-cleavage states targeting different cleavage sites. Our discoveries provide insights to fully elucidate the working mechanisms of Cas12a and to optimize it for genome engineering.

CeO2@PAA-LXW7 Attenuates LPS-Induced Inflammation in BV2 Microglia.

Microglia are the inherent immune effector cells in the central nervous system (CNS), are activated rapidly when the CNS is stimulated by ischaemia, infection, injury, etc. and participate in and aggravate the development of inflammatory reactions in the CNS. During the process of microglial activation, inflammatory factors such as TNF-α and IL-1ß and an abundance of reactive oxygen species (ROS)/reactive nitrogen species (RNS), are released by damaged nerve cells. LXW7 is a small molecule peptide and specifically binds with integrin αvß3. Cerium oxide nanoparticles (nanoceria) are strong free radical scavengers and are widely used in many studies. In this research, a model of inflammation was established using lipopolysaccharide (LPS) to induce BV2 microglia activation, and the effects of CeO2@PAA (synthetic nanoscale cerium oxide particles), LXW7 and CeO2@PAA-LXW7 were evaluated. We detected the expression level of inflammatory factors, the release of NO in BV2 cells and the generation of intracellular ROS. The expression levels of focal adhesion kinase (FAK) and signal transducer and activator of transcription 3 (STAT3) and their phosphorylated proteins were detected in BV2 microglia. We found that CeO2@PAA, LXW7 and CeO2@PAA-LXW7 all effectively inhibited the activation of BV2 microglia, reduced the production of cytokines and the release of NO and reduced the production of intracellular ROS. The three treatments all inhibited the phosphorylation of FAK and STAT3 in BV2 microglia. Regarding these effects, CeO2@PAA-LXW7 was more effective than the other two monotherapies. Our data indicate that CeO2@PAA, LXW7 and CeO2@PAA-LXW7 can exert a neuroprotective function by inhibiting the inflammatory response of LPS-induced BV2 microglia. LXW7 may inhibit the activation of FAK and STAT3 signals in combination with integrin αvß3 to restrain neuroinflammation and the antioxidative stress effect of cerium oxide; hence, CeO2@PAA-LXW7 can exert a more robust anti-inflammatory and neuroprotective effect via synergistically suppressing the ability of LXW7 to influence the integrin pathway and the free radical-scavenging ability of CeO2@PAA.

Fluorescent ZnO quantum dots synthesized with urea for the selective detection of Cr6+ ion in water with a wide range of concentrations.

Nearly monodisperse Zinc oxide (ZnO) quantum dots (QDs) displayed yellow fluorescence were synthesized using urea as dispersant. In this paper, urea-ZnO QDs were used as fluorescent probe to detect Cr6+ in solution. The emission from the as-synthesized urea-ZnO QDs is selectively quenched when Cr6+ ions were added. Moreover, there are two linear relationships between the quenching of fluorescence intensity and the Cr6+ concentrations ranging from 4 µM to 1000 µM, with the detection limit for Cr6+ at 19.53 nM (on basis of 3σ/slope criterion). The quenching of fluorescence is attributed to aggregation of the QDs and charge transfer between the QDs and Cr6+ by measurements of transmission electron microscopy (TEM) images, UV-visible absorption spectra and fluorescence lifetime.