Temporal interference stimulation targets deep primate brain.

Temporal interference (TI) stimulation, a novel non-invasive stimulation strategy, has recently been shown to modulate neural activity in deep brain regions of living mice. Yet, it is uncertain if this method is applicable to larger brains and whether the electric field produced under traditional safety currents can penetrate deep regions as observed in mice. Despite recent model-based simulation studies offering positive evidence at both macro- and micro-scale levels, the absence of electrophysiological data from actual brains hinders comprehensive understanding and potential application of TI. This study aims to directly measure the spatiotemporal properties of the interfered electric field in the rhesus monkey brain and to validate the effects of TI on the human brain. Two monkeys were involved in the measurement, with implantation of several stereo-electroencephalography (SEEG) depth electrodes. TI stimulation was applied to anesthetized monkeys using two pairs of surface electrodes at differing stimulation parameters. Model-based simulations were also conducted and subsequently compared with actual recordings. Additionally, TI stimulation was administered to patients with motor disorders to validate its effects on motor symptoms. Through the integration of computational electric field simulation with empirical measurements, it was determined that the temporally interfering electric fields in the deep central regions are capable of attaining a magnitude sufficient to induce a subthreshold modulation effect on neural signals. Additionally, an improvement in movement disorders was observed as a result of TI stimulation. This study is the first to systematically measure the TI electric field in living non-human primates, offering empirical evidence that TI holds promise as a more focal and precise method for modulating neural activities in deep regions of a large brain. This advancement paves the way for future applications of TI in treating neuropsychiatric disorders.

Toxic effects of metal copper stress on immunity, metabolism and pathologic changes in Chinese mitten crab (Eriocheir japonica sinensis).

Copper (Cu2+), which represents a major physiological challenge for crab culture, is ubiquitous in the aquatic culture environment, and gills are the first organs that come into direct contact with the environment. However, the molecular basis of the response of crabs to Cu2+ stress remains unclear. Here, we conducted a transcriptome and differential expression analysis on the gills from Chinese mitten crab unexposed and exposed to Cu2+ for 24 h. The comparative transcriptome analysis identified 2486 differentially expressed genes (DEGs). GO functional analysis and KEGG pathway analysis revealed some DEGs, which were mostly related to immunity, metabolism, osmotic regulation, Cu2+ homeostasis regulation, antioxidant activity, and detoxification process. Some pathways related to humoral and cellular immunity, such as phagosome, peroxisome, lysosome, mTOR signaling pathway, PI3K-Akt signaling pathway, Toll-like receptor signaling pathway, and T cell receptor signaling pathway were enhanced under Cu2+ stress. In addition, Cu2+ stress altered the expression patterns of key phagocytosis and apoptosis genes (lectin, cathepsin L, Rab7, and HSP70), confirming that Cu2+ can induce oxidative stress and eventually even apoptosis. Histological analysis revealed that the copper can induce damage at the cellular level. This comparative transcriptome analysis provides valuable molecular information to aid future study of the immune mechanism of Chinese mitten crab in response to Cu2+ stress and provides a foundation for further understanding of the effects of metal toxicity.

Evaluation of Volatile Compounds in Milks Fermented Using Traditional Starter Cultures and Probiotics Based on Odor Activity Value and Chemometric Techniques.

The volatile components of milks fermented using traditional starter cultures (Streptococcus thermophilus and Lactobacillus bulgaricus) and probiotics (Lactobacillus lactis, Lactobacillus bifidus, Lactobacillus casei, and Lactobacillus plantarum) were investigated by means of gas chromatography-mass spectrometry (GC-MS) combined with simultaneous distillation extraction (SDE). A total of 53 volatile compounds were detected, being 10 aldehydes, 11 ketones, 10 acids, 11 hydrocarbons, 7 benzene derivatives, and 4 other compounds. The starter culture was found to significantly affect the composition of volatile components in the fermented milks. Ketones and hydrocarbons were the dominant compounds in milk before fermentation, while acids were dominant compounds in the fermented samples. Compared with probiotics, there was greater abundance of volatile components in fermented milks with traditional strains. The importance of each volatile compound was assessed on the basis of odor, thresholds, and odor activity values (OAVs). Of the volatile compounds, 31 of them were found to be odor-active compounds (OAV > 1). The component with the highest OAVs in most samples was (E,E)-2,4-decadienal. Heatmap analysis and principal component analysis were employed to characterize the volatile profiles of milks fermented by different starter cultures. The results could help to better understand the influence of starter cultures on the odor quality of milks.

Regulation of gut microbiota on immune cell ferroptosis: A novel insight for immunotherapy against tumor.

Gut microbiota contributes to the homeostasis of immune system and is related to various diseases such as tumorigenesis. Ferroptosis, a new type of cell death, is also involved in the disease pathogenesis. Recent studies have found the correlations of gut microbiota mediated ferroptosis and immune cell death. Gut microbiota derived immunosuppressive metabolites, which can promote differentiation and function of immune cells, tend to inhibit ferroptosis through their receptors, whereas inflammatory metabolites from gut microbiota also affect the differentiation and function of immune cells and their ferroptosis. Thus, it is possible for gut microbiota to regulate immune cell ferroptosis. Indeed, gut microbiota metabolite receptor aryl hydrocarbon receptor (AhR) can affect ferroptosis of intestinal intraepithelial lymphocytes, leading to disease pathogenesis. Since immune cell ferroptosis in tumor microenvironment (TME) affects the occurrence and development of tumor, the modulation of gut microbiota in these cell ferroptosis might influence on the tumorigenesis, and also immunotherapy against tumors. Here we will summarize the recent advance of ferroptosis mediated by gut microbiota metabolites, which potentially acts as regulator(s) on immune cells in TME for therapy against tumor.

Preparation and recognition mechanism study of an scFv targeting chloramphenicol for a hybridization chain reaction-CRISPR/Cas12a amplified fluoroimmunoassay.

Recombinant antibody-based immunoassays have emerged as crucial techniques for detecting antibiotic residues in food samples. Developing a stable recombinant antibody production system and enhancing detection sensitivity are crucial for their biosensing applications. Here, we bioengineered a single-chain fragment variable (scFv) antibody to target chloramphenicol (CAP) using both Bacillus subtilis and HEK 293 systems, with the HEK 293-derived scFv demonstrating superior sensitivity. Computational chemistry analyses indicated that ASP-99 and ASN-102 residues in the scFv play key roles in antibody recognition, and the hydroxyl group near the benzene ring of the target molecule is critical for in antibody binding. Furthermore, we enhanced the scFv's biosensing sensitivity using an HCR-CRISPR/Cas12a amplification strategy in a streptavidin-based immunoassay. In the dual-step amplification process, detection limits for CAP in the HCR and HCR-CRISPR/Cas12a stages were significantly reduced to 55.23 pg/mL and 3.31 pg/mL, respectively. These findings introduce an effective method for developing CAP-specific scFv antibodies and also propose a multi-amplification strategy to increase immunoassay sensitivity. Additionally, theoretical studies also offer valuable guidance in CAP hapten design and genetic engineering for antibody modification.

Deletion of protein kinase C θ attenuates hepatic ischemia/reperfusion injury and further elucidates its mechanism in pathophysiology.

Objectives: Hepatic ischemia-reperfusion (HIR) is a severe process in pathophysiology that occurs clinically in hepatectomy, and hepatic transplantations. The present study aimed to investigate the effect of PKC θ deletion against HIR injury and elucidate its mechanism in pathophysiology. Materials and Methods: HIR injury was induced in wild-type and PKC θ deletion mice treated with or without heme. The ALT and AST levels were determined to evaluate liver function. HIR injury was observed via histological examination. Oxidative stress and inflammatory response markers, and their signaling pathways were detected. Results: The study found that PKC θ knockout decreased serum AST and ALT levels when compared to the WT mice. Furthermore, heme treatment significantly reduced the ALT and AST levels of the PKC θ deletion mice compared with the untreated PKC θ deletion mice. PKC θ deletion markedly elevated superoxide dismutase activity in the liver tissue, reduced malondialdehyde content in the tissue, and the serum TNF-α and IL-6 levels compared with the WT mice. Heme treatment was observed to elevate the activity of SOD and reduced MDA content and serum of TNF-α and IL 6 in the PKC θ deletion animals. Meanwhile, heme treatment increased HO-1 and Nrf 2 protein expression, and reduced the levels of TLR4, phosphorylated NF-κB, and IKB-α. Conclusion: These findings suggested that PKC θ deletion ameliorates HIR, and heme treatment further improves HIR, which is related to regulation of PKC θ deletion on Nrf 2/HO-1 and TLR4/NF-κB/IKB α pathway.

Gut microbial alterations in arginine metabolism determine bone mechanical adaptation.

Although mechanical loading is essential for maintaining bone health and combating osteoporosis, its practical application is limited to a large extent by the high variability in bone mechanoresponsiveness. Here, we found that gut microbial depletion promoted a significant reduction in skeletal adaptation to mechanical loading. Among experimental mice, we observed differences between those with high and low responses to exercise with respect to the gut microbial composition, in which the differential abundance of Lachnospiraceae contributed to the differences in bone mechanoresponsiveness. Microbial production of L-citrulline and its conversion into L-arginine were identified as key regulators of bone mechanoadaptation, and administration of these metabolites enhanced bone mechanoresponsiveness in normal, aged, and ovariectomized mice. Mechanistically, L-arginine-mediated enhancement of bone mechanoadaptation was primarily attributable to the activation of a nitric-oxide-calcium positive feedback loop in osteocytes. This study identifies a promising anti-osteoporotic strategy for maximizing mechanical loading-induced skeletal benefits via the microbiota-metabolite axis.

[APPL1-mediated effects of leptin on activity of GSK-3ß in C2C12 cell].

OBJECTIVE: To observe the effects of leptin on activity of GSK-3ß and explore its mechanism. METHODS: C2C12 myoblasts differentiated for 3 days into myotubes in differentiation medium. Myotubes were stimulated by leptin (100 nmol/L) for 0, 5, 15 or 30 min respectively. Western blot was used to detect the expression levels of GSK-3ß and phospho-GSK-3ß (ser-9). Co-immunoprecipitation (CO-IP) was performed to determine the relationship among APPL1, leptin receptor and GSK-3ß in the presence or absence of leptin. The expression level of GSK-3ß at phospho-GSK-3ß (ser-9) was detected in APPL1-suppressed C2C12 myotube while that of APPL1 at phospho-APPL1 (ser-401) determined in GSK-3ß overexpressed/inhibited C2C12 cell. RESULTS: Leptin time-dependently increased the phosphorylation level of GSK-3ß at ser-9 in C2C12 cell, and the pGSK-3ß level in cells incubated by leptin for 30 min was as 4.08 times as which in control cells (P < 0.01). The triple complex of APPL1, leptin receptor and GSK-3ß, in the presence of leptin, the binding capacity between APPL1 and GSK-3ß was stronger. The level of phospho-GSK-3ß was significantly lower in APPL1-suppressed C2C12 cell compared with that in control cells. And the phosphorylation of APPL1 at ser-401 could be induced by GSK-3ß. CONCLUSION: Leptin promotes muscle glycogen synthesis by inducing phosphorylation of GSK-3ß in C2C12 cell. Such a function may be mediated by the triple complex of APPL1, leptin receptor and GSK-3ß. Meanwhile, GSK-3ß can also increase the phosphorylation of APPL1 at ser-401.

Deep learning for detection of age-related macular degeneration: A systematic review and meta-analysis of diagnostic test accuracy studies.

OBJECTIVE: To evaluate the diagnostic accuracy of deep learning algorithms to identify age-related macular degeneration and to explore factors impacting the results for future model training. METHODS: Diagnostic accuracy studies published in PubMed, EMBASE, the Cochrane Library, and ClinicalTrails.gov before 11 August 2022 which employed deep learning for age-related macular degeneration detection were identified and extracted by two independent researchers. Sensitivity analysis, subgroup, and meta-regression were performed by Review Manager 5.4.1, Meta-disc 1.4, and Stata 16.0. The risk of bias was assessed using QUADAS-2. The review was registered (PROSPERO CRD42022352753). RESULTS: The pooled sensitivity and specificity in this meta-analysis were 94% (P = 0, 95% CI 0.94-0.94, I2 = 99.7%) and 97% (P = 0, 95% CI 0.97-0.97, I2 = 99.6%), respectively. The pooled positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the area under the curve value were 21.77(95% CI 15.49-30.59), 0.06 (95% CI 0.04-0.09), 342.41 (95% CI 210.31-557.49), and 0.9925, respectively. Meta-regression indicated that types of AMD (P = 0.1882, RDOR = 36.03) and layers of the network (P = 0.4878, RDOR = 0.74) contributed to the heterogeneity. CONCLUSIONS: Convolutional neural networks are mostly adopted deep learning algorithms in age-related macular degeneration detection. Convolutional neural networks, especially ResNets, are effective in detecting age-related macular degeneration with high diagnostic accuracy. Types of age-related macular degeneration and layers of the network are the two essential factors that impact the model training process. Proper layers of the network will make the model more reliable. More datasets established by new diagnostic methods will be used to train deep learning models in the future, which will benefit for fundus application screening, long-range medical treatment, and reducing the workload of physicians.

Preparation and Characterization of Multilayer pH-Responsive Hydrogel Loaded Ganoderma lucidum Peptides.

To develop a safe, targeted, and efficient assembly of a stable polypeptide delivery system, in this work, chitosan, sodium alginate, and sodium tripolyphosphate were used as materials for the preparation of hydrogels. M-SCT hydrogels were prepared by ionic gelation and the layer-by-layer (LBL) method. The composite hydrogels exhibited excellent pH sensitivity and Ganoderma lucidum peptides (GLP) loading capacity. The prepared hydrogels were characterized and evaluated. The internal three-dimensional network structure of the hydrogel was observed by scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy confirmed the electrostatic interactions among the components. X-ray diffraction (XRD) was used to observe the crystal structure of the hydrogel. The maximum peptide encapsulation efficiency was determined to be 81.73%. The digestion stability and thermal stability of M-SCT hydrogels loaded GLP were demonstrated to be improved. The amount of peptides released from the GLP/M-SCT-0.75 hydrogels in simulated gastric fluid was lower than 30%. In addition, the ABTS assays showed that the free radical scavenging ability of the GLP/M-SCT-0.75 hydrogels confirmed the efficacy of the hydrogels in retaining the antioxidant activity of GLP. The study suggested the M-SCT-0.75 hydrogels had a great deal of potential as a peptide carrier for oral delivery.

Screening of Single-Stranded DNA Aptamer Specific for Florfenicol and Application in Detection of Food Safety.

In this work, the single-stranded DNA (ssDNA) aptamers specific to florfenicol (FF) and having a high binding affinity were prepared using the magnetic bead-based systematic evolution of ligands by the exponential enrichment technique (MB-SELEX). After 10 rounds of the MB-SELEX screening, aptamers that can simultaneously recognize FF and its metabolite florfenicol amine (FFA) were obtained. The aptamer with the lowest dissociation constant (Kd) was truncated and optimized based on a secondary structure analysis. The optimal aptamer selected was Apt-14t, with a length of 43 nt, and its dissociation constant was 4.66 ± 0.75 nM, which was about 7 times higher than that of the full-length sequence. The potential binding sites and interactions with FF were demonstrated by molecular docking simulations. In addition, a colorimetric strategy for nanogold aptamers was constructed. The linear detection range of this method was 0.00128-500 ng/mL and the actual detection limit was 0.00128 ng/mL. Using this strategy to detect florfenicol in actual milk and eggs samples, the spiked recoveries were 88.9-123.1% and 84.0-112.2%, respectively, and the relative standard deviation was less than 5.6%, showing high accuracy.

In vitro selection and optimization of high-affinity aptamer for milk allergen α-lactalbumin and its application in dual-mode detection.

Milk is one of the most common sources of protein in people's daily lives, and it is also recognized by the World Health Organization (WHO) as one of the eight categories of food allergies to human beings. α-lactalbumin (α-La) is the main cause of milk allergy. In this study, a single-stranded DNA aptamer with high binding affinity to α-La were selected using systematic evolution of ligands by exponential enrichment (SELEX) method. Compared with the full-length sequence, the binding affinity of the truncated aptamer LA-1t for α-La was increased six times using fluorescence analysis. Circular dichroism (CD) indicated that the secondary structure of LA-1t contained a typical hairpin structure. Through the docking simulation of LA-1t and α-La, these experimental results were further explained theoretically, and the recognition mechanism was explained. Finally, the colorimetric and fluorescence signal of boron nitride quantum dots anchored to porous CeO2 nanorods (BNQDs/CeO2) were modulated by FAM-labeled LA-1t to achieve highly selective and sensitive determination of α-La. This dual-mode sensing strategy displayed sensitive recognition for α-La in a linear range of 5-4,000 ng/ml with the LOD was 3.32 ng/ml (colorimetry) and 0.71 ng/ml (fluorescence), respectively. Simultaneously, the colorimetry/fluorescence dual-mode sensing strategy was applied for detecting α-La in spiked real samples and demonstrated good stability and reliability.

Selection and Characterization of DNA Aptamers for Constructing Aptamer-AuNPs Colorimetric Method for Detection of AFM1.

Aflatoxin M1 (AFM1), one of the most toxic mycotoxins, is a feed and food contaminant of global concern. To isolate the ssDNA aptamer of AFM1, synthesized magnetic graphene oxide nanomaterials, 12 rounds of subtractive systematic evolution of ligands by exponential enrichment (SELEX) selection were carried out. As a result, 24 candidate aptamers were selected, and their sequence similarity exceeded 97%. Their binding affinity and specificity were further examined by fluorescence and biofilm interferometry (BLI) methods. One aptamer (Apt-5) against AFM1 with a high affinity and specificity was isolated and demonstrated to be the optimal aptamer, whose dissociation constant reached the nanomolar level, Kd = 8.12 ± 1.51 nM. Additionally, molecular docking studies were used to predict the possible binding sites and mechanisms of the two. Based on Apt-5, an unlabeled aptamer-AuNPs colorimetric method was established to detect AFM1 in milk with a linear range of 0.078-10 ng/mL, and the actual detection limit was 0.078 ng/mL. These results demonstrated that this detection technique could be useful for the quantitative determination of AFM1 in milk and dairy products.

SU5, a new Auraptene analog with improved metabolic stability, ameliorates nonalcoholic fatty liver disease in methionine- and choline-deficient diet-fed db/db mice.

Farnesoid X receptor (FXR) has been considered as a promising target for nonalcoholic steatohepatitis (NASH), while existing FXR agonists suffer from serious side effects. Thus, it is very necessary to identify novel FXR agonists with good safety. Auraptene (AUR) is a new FXR agonist with excellent safety and extensive pharmacological activities, while the lactone of AUR is vulnerable to esterolysis. In this study, the lactone of AUR was converted to metabolically stable amide moiety, and the obtained analog SU5 revealed comparable activity and better metabolic stability than that of AUR. In NASH model, SU5 showed stronger efficacy than AUR on fatty liver by upregulating gene expressions related to FXR in vivo. Moreover, SU5 improved lipid metabolism by downregulating the gene expressions of lipid synthesis, while upregulating the gene expressions of fatty acid ß-oxidation and triglyceride metabolism. Besides, the inflammation-related genes were significantly decreased in SU5-treated group. These positive results highlighted the pharmacological potential of SU5 for the treatment of NASH.

Nanozyme-enabled sensing strategies for determining the total antioxidant capacity of food samples.

Gold doped copper hexacyanoferrate (Au@Cu-HCF) nanozyme-based colorimetric sensing strategies were exploited to measure total antioxidant capacity (TAC) of some plant-derived food samples. The new developed Au@Cu-HCF nanozyme replaces natural enzymes to catalyze a redox reaction, and antioxidants can compete with substrates in the interaction with OH, leading to an antioxidant concentration-dependent color change. Depending on the Au@Cu-HCF-based ABTS colorimetric strategy, a smartphone-based sensor was devised using smartphone's camera as a "smart detector". The proposed sensor was successfully utilized to measure the TAC of lotus root (4.61 mM), citrus juice (6.35 mM), and lemon beverage (1.00 mM) with standard deviations of 0.16 mM, 0.16 mM, and 0.06 mM, respectively. These results all agree well with the commercial kit (4.55 mM for lotus root, 6.27 mM for citrus juice and 1.11 mM for lemon beverage), indicating this sensor has good practical applications in the TAC measurement of food samples.

A Novel Colorimetric Nano Aptasensor for Ultrasensitive Detection of Aflatoxin B1 Based on the Exonuclease III-Assisted Signal Amplification Approach.

The detection of aflatoxin B1 (AFB1) has recently garnered much attention on the issue of food safety. In this study, a novel and sensitive aptasensor towards AFB1 is proposed using an Exonuclease III (Exo III)-integrated signal amplification strategy. This reported sensing strategy is regulated by aptamer-functionalized nanobeads that can target AFB1; furthermore, complementary DNA (cDNA) strands can lock the immobilized aptamer strands, preventing the signal amplification function of Exo III in the absence of AFB1. The presence of AFB1 triggers the displacement of cDNA, which will then activate the Exo III-integrated signal amplification procedure, resulting in the generation of a guanine (G)-rich sequence to form a G-4/hemin DNAzyme, which can catalyze the substrate of ABTS to produce a green color. Using this method, a practical detection limit of 0.0032 ng/mL and a dynamic range of detection from 0.0032 to 50 ng/mL were obtained. Additionally, the practical application of the established sensing method for AFB1 in complex matrices was demonstrated through recovery experiments. The recovery rate and relative standard deviations (RSD) in three kinds of cereal samples ranged from 93.83% to 111.58%, and 0.82% to 7.20%, respectively, which were comparable with or better than previously reported methods.

A broad-spectrum sensing strategy for the tetracycline family of antibiotics based on an ovalbumin-stabilized gold nanocluster and its application in a pump-free microfluidic sensing platform.

With increasing concerns related to the abuse of antibiotics in livestock production worldwide, simple and rapid screening methods for monitoring antibiotics in animal-derived foods are highly desirable. In this study, we propose a facile synthesis strategy for gold nanoclusters (AuNCs) exhibiting remarkable optical properties by employing ovalbumin (OVA) as the template. The OVA-stabilized AuNCs (AuNCs@OVA) manifest intriguing multicolour fluorescence and a gradually declining fluorescence intensity at 650 nm with an increasing concentration of tetracycline family antibiotics (TCs) including tetracycline, chlorotetracycline, oxytetracycline, and doxycycline, which are a widely used class of antibiotics for treating infections in food-producing animals. This performance makes AuNCs@OVA particularly attractive as a broad-spectrum detector for TCs sensing, and we demonstrate that this simple sensing procedure can be realized in real time by directly mixing the target sample and AuNCs@OVA components. Based on this sensing strategy, a microfluidic lab-on-a-chip platform was constructed for the ultrarapid detection of TCs within 30 s. The detection limit was determined to be 0.09 µg/mL in chicken muscle extract, with the recovery ranging from 86.20% to 93.57% in spiked samples. This work provides not only a broad-spectrum sensing strategy for TCs but also a pump-free microfluidic chip with the advantages of being portable, ultrarapid, and low cost, offering a viable alternative for on-the-spot ultrarapid screening of TCs.

Anterior thalamic stimulation improves working memory precision judgments.

BACKGROUND: The anterior nucleus of thalamus (ANT) has been suggested as an extended hippocampal system. The circuit of ANT and hippocampus has been widely demonstrated to be associated with memory function. Both lesions to each region and disrupting inter-regional information flow can induce working memory impairment. However, the role of this circuit in working memory precision remains unknown. OBJECTIVE: To test the role of the hippocampal-anterior thalamic pathway in working memory precision, we delivered intracranially electrical stimulation to the ANT. We hypothesize that ANT stimulation can improve working memory precision. METHODS: Presurgical epilepsy patients with depth electrodes in ANT and hippocampus were recruited to perform a color-recall working memory task. Participants were instructed to point out the color they were supposed to recall by clicking a point on the color wheel, while the intracranial EEG data were synchronously recorded. For randomly selected half trials, a bipolar electrical stimulation was delivered to the ANT electrodes. RESULTS: We found that compared to non-stimulation trials, working memory precision judgements were significantly improved for stimulation trials. ANT electrical stimulation significantly increased spectral power of gamma (30-100 Hz) oscillations and decreased interictal epileptiform discharges (IED) in the hippocampus. Moreover, the increased gamma power during the pre-stimulus and retrieval period predicted the improvement of working memory precision judgements. CONCLUSION: ANT electrical stimulation can improve working memory precision judgements and modulate hippocampal gamma activity, providing direct evidence on the role of the human hippocampal-anterior thalamic axis in working memory precision.

Evaluation of Volatile Compounds during the Fermentation Process of Yogurts by Streptococcus thermophilus Based on Odor Activity Value and Heat Map Analysis.

The volatile composition of yogurt produced by Streptococcus thermophilus fermentation at different time points was investigated by gas chromatography-mass spectrometry combined with simultaneous distillation and extraction. A total of 53 volatile compounds including 11 aldehydes, 10 ketones, 8 acids, 7 benzene derivatives, 13 hydrocarbons, and 4 other compounds were identified in all of the samples. Ketones and hydrocarbons were the predominant volatile components in the early stage, whereas acids were the predominant volatiles in the late stage. The importance of each volatile was evaluated based on odor, threshold, and odor activity values (OAVs). Twenty-nine volatiles were found to be odor-active compounds (OAV > 1), among which (E, E)-2,4-decadienal had the highest OAV (14623-22278). Other aldehydes and ketones such as octanal, dodecanal, 2-nonen-4-one, and 2-undecanone also showed high odor intensity during fermentation. Heat map analysis was employed to evaluate the differences during fermentation. The results demonstrated that the volatile profile based on the content and OAVs of volatile compounds enables the good differentiation of yogurt during fermentation.

Cyclodextrin-Modified CeO2 Nanoparticles as a Multifunctional Nanozyme for Combinational Therapy of Psoriasis.

PURPOSE: Reactive oxygen species (ROS)-induced oxidative stress plays a key role in the pathogenesis and progression of psoriasis by causing inflammation. Antioxidative strategies eradicating ROS may serve as effective and easy treatment options for psoriasis, while nanozymes with intrinsic antioxidant enzyme-like activity have not been explored for psoriasis treatment. The aim of this study is to fabricate ß-cyclodextrins (ß-CDs)-modified ceria nanoparticles (ß-CDs/CeO2 NPs) with drug-loaded and multimimic-enzyme activities for combinational psoriasis therapy. METHODS: The ß-CDs/CeO2 NPs were synthesized by a hydrothermal method using unmodified ß-CDs as a protecting agent. The structure, size and morphology were analyzed by dynamic light scattering, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy. Considering the superoxide dismutase (SOD)- and catalase-mimetic activities, the in vitro antioxidant activity of the ß-CDs/CeO2 NPs was investigated. After dithranol (DIT) was loaded, the drug-loading capacity and release profile were determined by UV-visible light spectrophotometer and high-performance liquid chromatography. The anti-psoriatic efficacy was studied in the imiquimod (IMQ)-induced mouse model on the basis of morphological evaluation, psoriasis area and severity index calculation (PASI), and inflammatory cytokine expression. RESULTS: The average particle size of the blank ß-CDs/CeO2 NPs was 60.89±0.32 nm with a polydispersity index (PDI) of 0.12, whereas that of the DIT-loaded NPs was 79.38±1.06 nm with a PDI of 0.27. TEM results showed the as-prepared NPs formed a uniform quasi-spherical shape with low polydispersity. XPS indicates synthesized NPs have a mixed Ce3+/Ce4+ valence state. FTIR spectroscopy confirmed the presence of ß-CDs and DIT in the NPs. Inhibition of superoxide anion rate by NPs could be reached to 79.4% in the presence of 200 µg/mL, and elimination of H2O2 efficiency reached about 50% in the presence of 40 µg/mL, demonstrating excellent superoxide dismutase- and catalase-mimicking activities, thereby providing remarkable cryoprotection against ROS-mediated damage. Furthermore, ß-CDs on the surface endowed the NPs with drug-loading function via host-guest interactions. The entrapment efficiency and drug loading of DIT are 94.7% and 3.48%, respectively. The in vitro drug release curves revealed a suitable release capability of DIT@ß-CDs/CeO2 NPs under physiological conditions. In IMQ-induced psoriatic model, the DIT@ß-CDs/CeO2 NPs exhibited excellent therapeutic effect. CONCLUSION: This study may pave the way for the application of nanozyme ß-CDs/CeO2 NPs as a powerful tool for psoriasis therapy.