RIP3 orchestrates oxidative stress and pyroptosis in doxorubicin-induced cardiotoxicity through regulation of AKT/Nrf2 signaling cascade.

This study was designed to explore the role of RIP3 in DOX-induced cardiotoxicity and its underlying molecular mechanisms. Our results demonstrate that RIP3 exacerbates DOX-induced cardiotoxicity through promoting oxidative stress and pyroptosis by regulating the AKT/Nuclear factor erythroid 2-related factor 2 (Nrf2) signal pathway. Inhibition of RIP3 using GSK-872 attenuated DOX-induced cardiac remodeling and contractile dysfunction. Moreover, using GSK-872 in vivo, the results revealed that inhibition of RIP3 alleviated DOX-induced cardiotoxicity by the resulting inhibition of oxidative stress and pyroptosis. In addition, inhibition of RIP3 increased the protein levels of AKT and Nrf2 in DOX-treated mouse hearts. Furthermore, the AKT inhibitor LY294002 lessened RIP3 reduction-offered protection against DOX-induced H9c2 cell injury by moderating oxidative stress and pyroptosis. Taken together, these data demonstrate that RIP3 activation orchestrates DOX-induced cardiotoxicity through elevated oxidative stress and pyroptosis in an AKT/Nrf2-dependent manner. Those findings highlight the clinical relevance and therapeutic potential of targeting RIP3 for the treatment of DOX-induced cardiotoxicity.

Engineering an energy-dissipating hybrid tissue in vivo for obesity treatment.

Obesity is a global health challenge with limited therapeutic solutions. Here, we demonstrate the engineering of an energy-dissipating hybrid tissue (EDHT) in the body for weight control. EDHT is constructed by implanting a synthetic gel matrix comprising immunomodulatory signals and functional cells into the recipient mouse. The immunomodulatory signals induce the host stromal cells to create an immunosuppressive niche that protects the functional cells, which are overexpressing the uncoupling protein 1 (UCP1), from immune rejection. Consequently, these endogenous and exogenous cells co-develop a hybrid tissue that sustainedly produces UCP1 to accelerate the host's energy expenditure. Systematic experiments in high-fat diet (HFD) and transgenic (ob/ob) mice show that EDHT efficiently reduces body weight and relieves obesity-associated pathological conditions. Importantly, an 18-month observation for safety assessment excludes cell leakage from EDHT and reports no adverse physiological responses. Overall, EDHT demonstrates convincing efficacy and safety in controlling body weight.

Preparation, characterization, and application of gallic acid-mediated photodynamic chitosan-nanocellulose-based films.

In this study, an active film composed of gallic acid (GA), chitosan (CS), and cellulose nanocrystals (CNC) was prepared using a solution casting method and synergistic photodynamic inactivation (PDI) technology. Characterization of the film showed that the CS-CNC-GA composite film had high transparency and UV-blocking ability. The addition of GA (0.2 %-1.0 %) significantly enhanced the mechanical properties, water resistance, and thermal stability of the film. The tensile strength increased up to 46.30 MPa, and the lowest water vapor permeability was 1.16 × e-12 g/(cm·s·Pa). The PDI-treated CS-CNC-GA1.0 composite film exhibited significantly enhanced antibacterial activity, with inhibition zone diameters of 31.83 mm against Staphylococcus aureus and 21.82 mm against Escherichia coli. The CS-CNC-GA composite film also showed good antioxidant activity. Additionally, the CS-CNC-GA1.0 composite film generated a large amount of singlet oxygen under UV-C light irradiation. It was found that using the CS-CNC-GA1.0 composite film for packaging and storage of oysters at 4 °C effectively delayed the increase in pH, total colony count, and lipid oxidation in oysters. In conclusion, the CS-CNC-GA composite film based on PDI technology has great potential for applications in the preservation of aquatic products.

Small extracellular vesicles: Roles and clinical application in prostate cancer.

Prostate cancer is a significant health problem in the United States. It is remarkably heterogenous, ranging from slow growing disease amenable to active surveillance to highly aggressive forms requiring active treatments. Therefore, being able to precisely determine the nature of disease and appropriately match patients to available and/or novel therapeutics is crucial to improve patients' overall outcome and quality of life. Recently small extracellular vesicles (sEVs), a subset of nanoscale membranous vesicles secreted by various cells, have emerged as important analytes for liquid biopsy and promising vehicles for drug delivery. sEVs contain various biomolecules such as genetic material, proteins, and lipids that recapitulate the characteristics and state of their donor cells. The application of existing and newly developed technologies has resulted in an increased depth of knowledge about biophysical structures, biogenesis, and functions of sEVs. In prostate cancer patients, tumor-derived sEVs can be isolated from biofluids, commonly urine and blood. They mediate intercellular signaling within the tumor microenvironment and distal organ-specific sites, supporting cancer initiation, progression, and metastasis. A mounting body of evidence suggests that sEV components can be potent biomarkers for prostate cancer diagnosis, prognosis, and prediction of disease progression and treatment response. Due to enhanced circulation stability and bio-barrier permeability, sEVs can be also used as effective drug delivery carriers to improve the efficacy and specificity of anti-tumor therapies. This review discusses recent studies on sEVs in prostate cancer and is focused on their role as biomarkers and drug delivery vehicles in the clinical management of prostate cancer.

Hyperibone J exerts antidepressant effects by targeting ADK to inhibit microglial P2X7R/TLR4-mediated neuroinflammation.

INTRODUCTION: The antidepressant properties of Hypericum species are known. Hyperibone J, a principal component found in the flowers of Hypericum bellum, exhibited in vitro anti-inflammatory effects. However, the antidepressant effects and mechanisms of Hyperibone J remain to be elucidated. Adenosine kinase (ADK) is upregulated in epilepsy and depression and has been implicated in promoting neuroinflammation. OBJECTIVES: This study aimed to explore the impact of Hyperibone J on neuroinflammation-mediated depression and the mechanism underlying this impact. METHODS: This study employed acute and chronic in vivo depression models and an in vitro LPS-induced depression model using BV-2 microglia. The in vivo antidepressant efficacy of Hyperibone J was assessed through behavioral assays. Techniques such as RNA-seq, western blot, qPCR and ELISA were utilized to elucidate the direct target and mechanism of action of Hyperibone J. RESULTS: Compared with the model group, depression-like behaviors were significantly alleviated in the Hyperibone J group. Furthermore, Hyperibone J mitigated hippocampal neuroinflammation and neuronal damage. RNA-seq suggested that Hyperibone J predominantly influenced inflammation-related pathways. In vitro experiments revealed that Hyperibone J reversed the LPS-induced overexpression and release of inflammatory factors. Network pharmacology and various molecular biology experiments revealed that the potential binding of Hyperibone J at the ASN-312 site of ADK diminished the stability and protein expression of ADK. Mechanistic studies revealed that Hyperibone J attenuated the ADK/ATP/P2X7R/Caspase-1-mediated maturation and release of IL-1ß. The study also revealed a significant correlation between Tlr4 expression and depression-like behaviors in mice. Hyperibone J downregulated ADK, inhibiting Tlr4 transcription, which in turn reduced the phosphorylation of NF-κB and the subsequent transcription of Nlrp3, Il-1b, Tnf, and Il-6. CONCLUSION: Hyperibone J exerted antineuroinflammatory and antidepressant effects by binding to ADK in microglia, reducing its expression and thereby inhibiting the ATP/P2X7R/Caspase-1 and TLR4/NF-κB pathways. This study provides experimental evidence for the therapeutic potential of Hypericum bellum.

Corrigendum: Tracheal intubation in patients with Pierre Robin sequence: development, application, and clinical value based on a 3-dimensional printed simulator.

[This corrects the article DOI: 10.3389/fphys.2023.1292523.].

Prostate cancer reshapes the secreted and extracellular vesicle urinary proteomes.

Urine is a complex biofluid that reflects both overall physiologic state and the state of the genitourinary tissues through which it passes. It contains both secreted proteins and proteins encapsulated in tissue-derived extracellular vesicles (EVs). To understand the population variability and clinical utility of urine, we quantified the secreted and EV proteomes from 190 men, including a subset with prostate cancer. We demonstrate that a simple protocol enriches prostatic proteins in urine. Secreted and EV proteins arise from different subcellular compartments. Urinary EVs are faithful surrogates of tissue proteomes, but secreted proteins in urine or cell line EVs are not. The urinary proteome is longitudinally stable over several years. It can accurately and non-invasively distinguish malignant from benign prostatic lesions and can risk-stratify prostate tumors. This resource quantifies the complexity of the urinary proteome and reveals the synergistic value of secreted and EV proteomes for translational and biomarker studies.

Extracellular vesicles activated cancer-associated fibroblasts promote lung cancer metastasis through mitophagy and mtDNA transfer.

BACKGROUND: Studies have shown that oxidative stress and its resistance plays important roles in the process of tumor metastasis, and mitochondrial dysfunction caused by mitochondrial DNA (mtDNA) damage is an important molecular event in oxidative stress. In lung cancer, the normal fibroblasts (NFs) are activated as cancer-associated fibroblasts (CAFs), and act in the realms of the tumor microenvironment (TME) with consequences for tumor growth and metastasis. However, its activation mechanism and whether it participates in tumor metastasis through antioxidative stress remain unclear. METHODS: The role and signaling pathways of tumor cell derived extracellular vesicles (EVs) activating NFs and the characteristic of induced CAFs (iCAFs) were measured by the transmission electron microscopy, nanoparticle tracking analysis, immunofluorescence, collagen contraction assay, quantitative PCR, immunoblotting, luciferase reporter assay and mitochondrial membrane potential detection. Mitochondrial genome and single nucleotide polymorphism sequencing were used to investigate the transport of mtDNA from iCAFs to ρ0 cells, which were tumor cells with mitochondrial dysfunction caused by depletion of mtDNA. Further, the effects of iCAFs on mitochondrial function, growth and metastasis of tumor cells were analysed in co-culture models both in vitro and in vivo, using succinate dehydrogenase, glutathione and oxygen consumption rate measurements, CCK-8 assay, transwell assay, xenotransplantation and metastasis experiments as well as in situ hybridization and immunohistochemistry. RESULTS: Our findings revealed that EVs derived from high-metastatic lung cancer cells packaged miR-1290 that directly targets MT1G, leading to activation of AKT signaling in NFs and inducing NFs conversion to CAFs. The iCAFs exhibit higher levels of autophagy and mitophagy and more mtDNA release, and reactive oxygen species (ROS) could further promote this process. After cocultured with the conditioned medium (CM) of iCAFs, the ρ0 cells may restore its mitochondrial function by acquisition of mtDNA from CAFs, and further promotes tumor metastasis. CONCLUSIONS: These results elucidate a novel mechanism that CAFs activated by tumor-derived EVs can promote metastasis by transferring mtDNA and restoring mitochondrial function of tumor cells which result in resistance of oxidative stress, and provide a new therapeutic target for lung cancer metastasis.

Echocardiographic assessment for cardiopulmonary function in patients with congenital heart disease-related pulmonary arterial hypertension.

BACKGROUND: For patients with congenital heart disease-related pulmonary arterial hypertension (CHD-PAH), cardiopulmonary exercise testing (CPET) can reflect cardiopulmonary reserve function. However, CPET may not be readily accessible for patients with high-risk conditions or limited mobility due to disability. Echocardiography, on the other hand, serves as a widely available diagnostic tool for all CHD-PAH patients. This study was aimed to identify the parameters of echocardiography that could serve as indicators of cardiopulmonary function and exercise capacity. METHODS: A cohort of 70 patients contributed a total of 110 paired echocardiogram and CPET results to this study, with 1 year interval for repeated examinations. Echocardiography and exercise testing were conducted following standardized procedures, and the data were collected together with clinically relevant indicators for subsequent statistical analysis. Demographic comparisons were performed using t-tests and chi-square tests. Univariate and multivariate analyses were conducted to identify potential predictors of peak oxygen uptake (peak VO2) and the carbon dioxide ventilation equivalent slope (VE/VCO2 slope). Receiver operating characteristic (ROC) analysis was used to assess the performance of the parameters. RESULTS: The ratio of tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP) was found to be the only independent indicator significantly associated with both peak VO2 and VE/VCO2 slope (both p < 0.05). Additionally, left ventricular ejection fraction (LVEF) and right ventricular fractional area change (FAC) were independently correlated with the VE/VCO2 slope (both p < 0.05). TAPSE/PASP showed the highest area under the ROC curve (AUC) for predicting both a peak VO2 ≤ 15 mL/kg/min and a VE/VCO2 slope ≥ 36 (AUC = 0.91, AUC = 0.90, respectively). The sensitivity and specificity of TAPSE/PASP at the optimal threshold exceeded 0.85 for both parameters. CONCLUSIONS: TAPSE/PASP may be a feasible echocardiographic indicator for evaluating exercise tolerance.

Self-efficacy mediates the effect of professional identity on learning engagement for nursing students in higher vocational colleges: A cross-sectional study.

BACKGROUND: Learning engagement is a crucial predictor of academic achievement. It is essential to understand the factors influencing learning engagement among nursing students, especially from the learner's perspective, which is notably scarce but vital for designing effective educational interventions. OBJECTIVES: This study aims to investigate the mediating effect of self-efficacy on the relationship between professional identity and learning engagement for nursing students in higher vocational colleges. DESIGN: A cross-sectional electronic survey was conducted. SETTING: The study was conducted in four higher vocational colleges located in Guangdong Province, China. PARTICIPANTS: A total of 944 first- and second-year nursing students participated in the study between October and November 2022. METHODS: Data were collected with questionnaires on general information, professional identity, self-efficacy, and learning engagement and analyzed with SPSS 26.0 and PROCESS v4.1 (Model 4), exploring relationships among professional identity, self-efficacy, and learning engagement through Pearson correlations, multivariate regression, and mediation analysis with 5000 bootstrap samples. RESULTS: The participants exhibited moderate levels of professional identity (85.37 ± 13.52), self-efficacy (25.58 ± 5.74), and learning engagement (71.26 ± 16.17), which were all significantly correlated with each other (P < 0.01). In the model of the mediating effect, professional identity directly (ß = 0.811, t = 27.484, P < 0.001) and indirectly [ß = 0.112,95%CI (0.074-0.154)] significantly predicts college students' learning engagement; professional identity has a significant positive predictive effect on self-efficacy (ß = 0.182, t = 14.459, P < 0.001) and self-efficacy significantly predicts learning engagement (ß = 0.614, t = 8.292, P < 0.001). Furthermore, the direct effect of professional identity on learning engagement (0.699) and its mediating effect (0.112) account for 86.19 % and 13.81 % of the total effect (0.811), respectively. CONCLUSION: Participants exhibited moderate levels of professional identity, self-efficacy, and learning engagement. Professional identity and self-efficacy are interconnected and positively correlated, influencing learning engagement among nursing students, which highlights the need to foster these qualities to enhance education and future practice.

New risk model by right ventricle - pulmonary arterial coupling and inferior vena cava from echocardiography in patients with conventional low-intermediate risk pulmonary artery hypertension under targeted treatment.

BACKGROUND: Accurately stratifying patients with pulmonary arterial hypertension (PAH) is very important, and traditional risk scores still have internal heterogeneity. This study aimed to construct a risk stratification model that can accurately identify clinical worsening (CW) events in conventional low-intermediate risk patients with pulmonary hypertension under targeted drug treatment by using echocardiographic parameters. METHODS: This study is a single-center, prospective study, including 105 PAH patients who underwent regular follow-up at Guangdong Provincial People's Hospital from October 2021 to April 2023. The primary endpoint was the occurrence of CW, including death, hospitalization due to pulmonary hypertension, escalation of targeted drug therapy, and worsening of PAH. The predictive value of the echocardiography-based three-strata risk model was assessed using Kaplan-Meier curves and COX regression analysis. RESULTS: A total of 98 PAH patients were ultimately included in this study. The median follow-up duration was 26 months (range 7-28 months). The echocardiography-based three-strata model included the ratio of tricuspid annular plane systolic excursion and pulmonary artery systolic pressure (TAPSE/PASP) and inferior vena cava (IVC). The echocardiography-based three-strata model had higher diagnostic value (C-index = .76) compared to the 2022 ESC/ERS three-strata model and four-strata model (C-index = .66 and C-index = .61, respectively). PAH patients with lower TAPSE/PASP and wider IVC showed a higher CW rate compared to patients with higher TAPSE/PASP and normal IVC (HR = 15.1, 95%CI:4.4-51.9, p < .001). CONCLUSION: The echocardiography-based three-strata model based on TAPSE/PASP and IVC can effectively improve the stratification of low-intermediate risk PAH patients under targeted treatment.

Dynamic temporal neural patterns based on multichannel LFPs Identify different brain states during anesthesia in pigeons: comparison of three anesthetics.

Anesthetic-induced brain activity study is crucial in avian cognitive-, consciousness-, and sleep-related research. However, the neurobiological mechanisms underlying the generation of brain rhythms and specific connectivity of birds during anesthesia are poorly understood. Although different kinds of anesthetics can be used to induce an anesthesia state, a comparison study of these drugs focusing on the neural pattern evolution during anesthesia is lacking. Here, we recorded local field potentials (LFPs) using a multi-channel micro-electrode array inserted into the nidopallium caudolateral (NCL) of adult pigeons (Columba livia) anesthetized with chloral hydrate, pelltobarbitalum natricum or urethane. Power spectral density (PSD) and functional connectivity analyses were used to measure the dynamic temporal neural patterns in NCL during anesthesia. Neural decoding analysis was adopted to calculate the probability of the pigeon's brain state and the kind of injected anesthetic. In the NCL during anesthesia, we found elevated power activity and functional connectivity at low-frequency bands and depressed power activity and connectivity at high-frequency bands. Decoding results based on the spectral and functional connectivity features indicated that the pigeon's brain states during anesthesia and the injected anesthetics can be effectively decoded. These findings provide an important foundation for future investigations on how different anesthetics induce the generation of specific neural patterns.

First Report of Diaporthe hongkongensis Causing Leaf Blight on Macadamia in China.

Macadamia (Macadamia ternifolia Maiden and Betche) belongs to the Proteaceae family (Li et al. 2022). In the hilly areas of Guangxi (southern China), macadamia trees are an important source of revenue. The planting area in Guangxi has increased in recent years, exceeding 53,333 hectares by the end of 2022, but this increase is also associated with emergency of, macadamia diseases. Leaf blight symptoms were observed in 37/241 macadamia trees (15% incidence) in a plantation in Nanning, Guangxi province in China, during June, 2022. Disease severity on infected trees ranged from 5% to 60%. The disease developed from the tips or margins of leaves, causing the leaves to turn brown, and later gradually withered (Fig. 1 A). Ten leaves with lesions were collected from five macadamia trees (two leaves per tree. Thereafter, small segments (3 to 4 mm²) excised from the margins of ten lesions were surface sterilized in 75% ethanol for 30 s and 1% hypochlorite for 90 s and Page 1 of 6 2 rinsed in sterile water, before plating onto potato dextrose agar (PDA) medium. Plates were incubated under lighting during the daytime, and darkness at night-time for 5 days at 25℃. Twenty-two purified colonies were generated by subculturing hyphal tips, of which eight exhibited similar morphology and were further characterized. The colonies on PDA were gray with a white outer ring and flat lawn on the surface (Fig. 1 B). The pycnidia were superficial to semi-immersed on PDA, solitary to aggregated, globose to sub-globose, brown to black and oozed yellow mucilaginous masses (Fig.1 C). The α-conidia were unicellular, hyaline elliptical or fusiform, and measuring 4-8 × 1.9-4 µm (n=30) ， whereas the ß-conidia were hyaline, long, straight or curved, measuring 20-23 × 0.9-2 µm (n=30) (Fig. 1 D-E). The morphological features were similar to Diaporthe hongkongensis (Dissanayake et al. 2015). The eight morphologically similar isolates were identified as D. hongkongensis using the internal transcribed spacer (ITS) region, but only one isolate, JG11, was selected for further molecular identification. Five target genes, including the ITS region, translation elongation factor 1 alpha (EF1-α), beta-tubulin genes (TUB2), calmodulin (CAL), and histone H3 (HIS) were amplified and sequenced using primers ITS1/ITS4, EF1-728F/EF1-986R, Bt2a/Bt2b, CAL-228F/CAL-737R, and CYLH3F/H3-1b, respectively (Carbone and Kohn 1999). The sequences were deposited in GenBank under accession numbers OQ932790 (ITS) and OR147955-58 for EF1-α, TUB, CAL and HIS genes, respectively. BLAST search of GenBank showed that ITS, EF1-α, TUB, CAL, and HIS sequences of JG11 were similar to Page 2 of 6 3 those of D. hongkongensis NR111848 (99.22% identity), KY433566 (99.72%), MW208603 (99.42%), MW221740 (99.80%), and MW221661 (99.79%), respectively. Phylogenetic analysis of concatenated sequences was performed with IQ-TREE software. JG11 was grouped in the same clade as other Diaporthe hongkongensis isolates (Fig. 2). Pathogenicity experiments were carried out on healthy macadamia trees in a greenhouse. Three macadamia trees were used as negative controls where five uninjured leaves per tree were sprayed with sterile distilled water. Uninjured five leaves per tree of three other macadamia trees were sprayed with conidia suspension of the isolate JG11 at a concentration of 1×106. Each treatment was repeated 3 times independently, with 5 leaves per tree (Liu et al. 2023; Havill et al. 2023; Zhang et al. 2022). Plastic bags were placed over all inoculated leaves. The average daily temperature and relative humidity in the greenhouse were 32°C and 65%, respectively. Two days later, browning appeared on the leaves inoculated with the spore suspension and expanded outward. After 5 days, all macadamia leaves inoculated with the fungal spores began to wither, while controls remained asymptomatic (Fig. 1 H-I). D. hongkongensis was consistently re-isolated and purified from inoculated leaves and the identity was confirmed by morphological identification and molecular analysis, completed Koch's postulates. D. hongkongensis has been reported on peach (Zhang et al. 2021), grapevine trunk (Dissanayake et al. 2015) and Cunninghamia lanceolata (Liao et al. 2022). To our knowledge, this is the first report of D. hongkongensis causing leaf blight on macadamia in China. These findings provide a foundation for future research on the epidemiology and control of this newly emerging disease of macadamia.

Follistatin-like protein 1 attenuates doxorubicin-induced cardiomyopathy by inhibiting MsrB2-mediated mitophagy.

Doxorubicin (DOX) is a potent chemotherapeutic drug; however, its clinical use is limited due to its cardiotoxicity. Mitochondrial dysfunction plays a vital role in the pathogenesis of DOX-induced cardiomyopathy. Follistatin-like protein 1 (FSTL1) is a potent cardiokine that protects the heart from diverse cardiac diseases, such as myocardial infarction, cardiac ischemia/reperfusion injury, and heart failure. However, its role in DOX-induced cardiomyopathy is unclear. Therefore, the present study investigated whether administering recombinant FSTL1 could mitigate DOX-induced cardiomyopathy and clarified the underlying molecular mechanisms. FSTL1 treatment attenuated DOX-induced cardiac dysfunction, cardiac fibrosis, and cellular apoptosis by inhibiting excess mitochondrial matrix protein methionine sulfoxide reductase B2 (MsrB2)-mediated mitophagy. Furthermore, FSTL1 administration reduced the expression of apoptotic proteins, including MsrB2, Bax, caspase 3, mitochondrial Parkin, and LC3-II, increased myocardial ATP content, and decreased cardiac malondialdehyde levels, thus protecting mitochondrial function against DOX-induced cardiac injury. Furthermore, FSTL1 treatment protected the contractile properties of adult cardiomyocytes against DOX-induced injury in vitro. Furthermore, carbonyl cyanide m-chlorophenylhydrazone, a mitophagy inducer, impaired the protective effects of FSTL1 in DOX-treated H9c2 cardiomyocytes. In conclusion, these results show that FSTL1 is a novel therapeutic agent against DOX-induced cardiotoxicity that improves mitochondrial function and decreases mitophagy.

Decoding Typical Flight States Based on Neural Signals from the Midbrain Motor Nuclei of Pigeons.

BACKGROUND: Exploring the neural encoding mechanism and decoding of motion state switching during flight can advance our knowledge of avian behavior control and contribute to the development of avian robots. However, limited acquisition equipment and neural signal quality have posed challenges, thus we understand little about the neural mechanisms of avian flight. METHODS: We used chronically implanted micro-electrode arrays to record the local field potentials (LFPs) in the formation reticularis medialis mesencephali (FRM) of pigeons during various motion states in their natural outdoor flight. Subsequently, coherence-based functional connectivity networks under different bands were constructed and the topological features were extracted. Finally, we used a support vector machine model to decode different flight states. RESULTS: Our findings indicate that the gamma band (80-150 Hz) in the FRM exhibits significant power for identifying different states in pigeons. Specifically, the avian brain transmitted flight related information more efficiently during the accelerated take-off or decelerated landing states, compared with the uniform flight and baseline states. Finally, we achieved a best average accuracy of 0.86 using the connectivity features in the 80-150 Hz band and 0.89 using the fused features for state decoding. CONCLUSIONS: Our results open up possibilities for further research into the neural mechanism of avian flight and contribute to the understanding of flight behavior control in birds.

Detection and quantification of biogenic amines in cephalopod using dansyl chloride pre-column derivatization-HPLC and their production.

The accurate detection of biogenic amines (BAs) is an important means of ensuring the quality and safety of cephalopod seafood products. In this study, the pre-column derivatization of high-performance liquid chromatography (HPLC) was optimized using dansyl chloride (Dns-Cl) to detect BAs in octopus, cuttlefish, and squid. The reasons for the formation of BAs were investigated by assessing their decarboxylase activity and the rates of decomposition. The findings demonstrated that using Dns-Cl to optimize pre-column derivatization enabled the separation of nine different BAs. The detection limits ranged from 0.07 to 0.25 mg/L, and the results exhibited a high level of linearity (R2 ≥ 0.997). The decarboxylase activity and biodegradation rate positively correlated with the formation of BAs at temperatures below 0°C. Notably, the decarboxylase activity of octopus, cuttlefish, and squid exhibited a significant increase with prolonged storage time, and formyltransferase and carbamate kinase may be the key decarboxylase in cephalopod products. These findings serve as a valuable reference for further investigations into the mechanisms behind BAs production and the development of control technologies for BAs in cephalopod products. This study has successfully demonstrated the effectiveness of the Dns-Cl pre-column derivatization-HPLC method in accurately and efficiently detecting BAs in octopus, cuttlefish, and squid. Moreover, it highlights the influence of decarboxylase content and biodegradation rate on the formation of BAs. Importantly, this method can serve as a reference for detecting BAs in various seafood products.

The Hippocampus in Pigeons Contributes to the Model-Based Valuation and the Relationship between Temporal Context States.

Model-based decision-making guides organism behavior by the representation of the relationships between different states. Previous studies have shown that the mammalian hippocampus (Hp) plays a key role in learning the structure of relationships among experiences. However, the hippocampal neural mechanisms of birds for model-based learning have rarely been reported. Here, we trained six pigeons to perform a two-step task and explore whether their Hp contributes to model-based learning. Behavioral performance and hippocampal multi-channel local field potentials (LFPs) were recorded during the task. We estimated the subjective values using a reinforcement learning model dynamically fitted to the pigeon's choice of behavior. The results show that the model-based learner can capture the behavioral choices of pigeons well throughout the learning process. Neural analysis indicated that high-frequency (12-100 Hz) power in Hp represented the temporal context states. Moreover, dynamic correlation and decoding results provided further support for the high-frequency dependence of model-based valuations. In addition, we observed a significant increase in hippocampal neural similarity at the low-frequency band (1-12 Hz) for common temporal context states after learning. Overall, our findings suggest that pigeons use model-based inferences to learn multi-step tasks, and multiple LFP frequency bands collaboratively contribute to model-based learning. Specifically, the high-frequency (12-100 Hz) oscillations represent model-based valuations, while the low-frequency (1-12 Hz) neural similarity is influenced by the relationship between temporal context states. These results contribute to our understanding of the neural mechanisms underlying model-based learning and broaden the scope of hippocampal contributions to avian behavior.

Phase-Amplitude Coupling between Theta Rhythm and High-Frequency Oscillations in the Hippocampus of Pigeons during Navigation.

Navigation is a complex task in which the hippocampus (Hp), which plays an important role, may be involved in interactions between different frequency bands. However, little is known whether this cross-frequency interaction exists in the Hp of birds during navigation. Therefore, we examined the electrophysiological characteristics of hippocampal cross-frequency interactions of domestic pigeons (Columba livia domestica) during navigation. Two goal-directed navigation tasks with different locomotor modes were designed, and the local field potentials (LFPs) were recorded for analysis. We found that the amplitudes of high-frequency oscillations in Hp were dynamically modulated by the phase of co-occurring theta-band oscillations both during ground-based maze and outdoor flight navigation. The high-frequency amplitude sub-frequency bands modulated by the hippocampal theta phase were different at different tasks, and this process was independent of the navigation path and goal. These results suggest that phase-amplitude coupling (PAC) in the avian Hp may be more associated with the ongoing cognitive demands of navigational processes. Our findings contribute to the understanding of potential mechanisms of hippocampal PAC on multi-frequency informational interactions in avian navigation and provide valuable insights into cross-species evolution.

Dynamics Learning Rate Bias in Pigeons: Insights from Reinforcement Learning and Neural Correlates.

Research in reinforcement learning indicates that animals respond differently to positive and negative reward prediction errors, which can be calculated by assuming learning rate bias. Many studies have shown that humans and other animals have learning rate bias during learning, but it is unclear whether and how the bias changes throughout the entire learning process. Here, we recorded the behavior data and the local field potentials (LFPs) in the striatum of five pigeons performing a probabilistic learning task. Reinforcement learning models with and without learning rate biases were used to dynamically fit the pigeons' choice behavior and estimate the option values. Furthemore, the correlation between the striatal LFPs power and the model-estimated option values was explored. We found that the pigeons' learning rate bias shifted from negative to positive during the learning process, and the striatal Gamma (31 to 80 Hz) power correlated with the option values modulated by dynamic learning rate bias. In conclusion, our results support the hypothesis that pigeons employ a dynamic learning strategy in the learning process from both behavioral and neural aspects, providing valuable insights into reinforcement learning mechanisms of non-human animals.