Basis Of Function Research Articles

Target analyses by transcriptome sequencing in peripheral blood cells of grass carp: Potent immune responses in leukocytes and thrombocytes against bacterial and viral infections

Fishes provide abundant protein for humanity, while they are ravaging by bacterial and viral diseases. The defense based on peripheral blood cell immunity is an important means to resist pathogenic infections. However, the immune response of different blood cell communities to bacterial or viral infection remains largely unknown. In this study, grass carp (Ctenopharyngodon idella), the most productive fish in the world, was employed to comprehensively investigate the immune responses of erythrocytes, leukocytes, and thrombocytes after Aeromonas hydrophila or type II grass carp reovirus (GCRV-II) infection by transcriptome sequencing. The data of 45 samples with small intra-group and large inter-group differences were obtained. There were 3921, 15,378, 7019 DEGs in the infected erythrocytes, leukocytes, and thrombocytes, respectively. Through GO and KEGG analysis, they were mainly enriched in the items related to innate and adaptive immunity, including pattern recognition receptor signaling pathways and cytokine signaling pathways. Therefore, we conducted target analyses of vital immune families, including TLRs, RLRs, IFNs, IRFs, immune activators, and antigen presentation genes, systematically clarified the immune responses of blood cells to pathogenic infections. All the three types of blood cells expressed a large number of immune genes involved in anti-infection to varying degrees, among them leukocytes and thrombocytes responded aggressively. This study provides implications for the function of peripheral blood cells and the functional basis of immune genes in pathogenic infections.

Systematic Characterization of Triterpenoids in Ganoderma lucidum by UHPLC-Q/TOF MS

Background: Ganoderma lucidum, which is widely used as “Ganoderma” in China or other Asian countries (Japan, Korea, etc), exerts an important role in tonifying qi and calming the mind in clinical applications. Triterpenoids are the main active components in Ganoderma lucidum, with significant biological activities of hepatoprotective, anticancer, and anti-tumor, etc. However, the current analysis of triterpenoids in Ganoderma lucidum by mass spectrometry is limited, restricting its quality control and elucidation of its functional basis. Objective: This work aimed to systematically characterize the triterpenoids in Ganoderma lucidum. Methods: The Ganoderma lucidum powder was extracted by 50% ethanol/water and separated by Waters ACQUITY UPLC HSS T3 column (2.1 mm×100 mm, 1.8 μm). The data was obtained by Waters G2-Q-TOF mass spectrometry equipped with an electrospray ionization ion (ESI) source, and the MS data under positive and negative modes was acquired and analyzed. Results: A total of 43 triterpenoids were identified or tentatively characterized from the extracts of Ganoderma lucidum, including 32 known compounds and 11 potential new compounds. Among them, five triterpenoids were unambiguously identified by comparison with reference standards, including ganoderic acid A(28), ganoderic acid D(36), ganoderenic acid D(34), ganoderic acid F(43), and ganoderic acid G(16). The profiled triterpenoids could be divided into eight types according to the substituents at the C3, C7 and C15 positions of the parent structure. The mass fragmentation rules of Ganoderma lucidum triterpenoids were summarized. Under the positive ion mode, Ganoderma lucidum triterpenoids easily lost CH3 at the C10 position and H2O at C3, C7, and C15 positions, and the side chain bond at the C22(23) position was easily split. Under the negative ion mode, the split of the C and D rings was the characteristic feature. result: A total of 43 triterpenoids were identified or tentatively characterized from the extracts of Ganoderma lucidum, including 32 known compounds and 11 potential new compounds. Among them, five triterpenoids were unambitiously identified by comparison with reference standards, including ganoderic acid A(28), ganoderic acid D(36), ganoderenic acid D(34), ganoderic acid F(43), and ganoderic acid G(16). These triterpenoids could be divided into eight types according to the substituents at the C3, C7 and C15 positions of the parent structure. The mass fragmentation rules of Ganoderma lucidum triterpenoids were summarized. Under the positive ion mode, Ganoderma lucidum triterpenoids easily lost CH3 at the C10 position and H2O at C3, C7, C15 position, and the side chain bond at C22(23) position was easily cracked. Under the negative ion mode, the crack of the C and D rings was the characteristic feature. Conclusion: The mass fragmentation behaviors of Ganoderma lucidum triterpenoids under positive ion mode were summarized and emphasized, and reliable scientific data and methods for systematic characterization of Ganoderma lucidum triterpenoids were also supplied.

Unveiling the Druggable Landscape of Bacterial Peptidyl tRNA Hydrolase: Insights into Structure, Function, and Therapeutic Potential.

Bacterial peptidyl tRNA hydrolase (Pth) or Pth1 emerges as a pivotal enzyme involved in the maintenance of cellular homeostasis by catalyzing the release of peptidyl moieties from peptidyl-tRNA molecules and the maintenance of a free pool of specific tRNAs. This enzyme is vital for bacterial cells and an emerging drug target for various bacterial infections. Understanding the enzymatic mechanisms and structural intricacies of bacterial Pth is pivotal in designing novel therapeutics to combat antibiotic resistance. This review provides a comprehensive analysis of the multifaceted roles of Pth in bacterial physiology, shedding light on its significance as a potential drug target. This article delves into the diverse functions of Pth, encompassing its involvement in ribosome rescue, the maintenance of a free tRNA pool in bacterial systems, the regulation of translation fidelity, and stress response pathways within bacterial systems. Moreover, it also explores the druggability of bacterial Pth, emphasizing its promise as a target for antibacterial agents and highlighting the challenges associated with developing specific inhibitors against this enzyme. Structural elucidation represents a cornerstone in unraveling the catalytic mechanisms and substrate recognition of Pth. This review encapsulates the current structural insights of Pth garnered through various biophysical techniques, such as X-ray crystallography and NMR spectroscopy, providing a detailed understanding of the enzyme's architecture and conformational dynamics. Additionally, biophysical aspects, including its interaction with ligands, inhibitors, and substrates, are discussed, elucidating the molecular basis of bacterial Pth's function and its potential use in drug design strategies. Through this review article, we aim to put together all the available information on bacterial Pth and emphasize its potential in advancing innovative therapeutic interventions and combating bacterial infections.

Investigation of infra-red spectra of three chiral liquid crystalline compounds with different fluorosubstitution of benzene ring

The IR spectra of three liquid crystalline compounds, differing only by the number of fluorine atoms in the molecular core, are investigated. The DFT+D3/BLYP-def2SVP calculations for isolated molecules are applied for the band assignments of the experimental IR spectra collected in the crystal phase. Additional DFT calculations, including the B3LYP exchange-correlation functional and def2TZVPP basis set, are also performed for the compound without the fluorine atoms in the molecular core. The scaling factors between the experimental and calculated peak positions, obtained at different levels of theory, are compared. For all compounds, the absorption bands assigned to the C=O stretching vibrations are analyzed as a function of temperature in the isotropic liquid, smectic phases, and crystal phase. The formation of hydrogen bonding involving the C=O groups during crystallization is inferred. The differences in the crystallization temperature of three compounds and the presence of the hexatic smectic phase for only one compound are discussed.

Ubiquitin ligase subunit FBXO9 inhibits V-ATPase assembly and lung cancer metastasis.

e20520 Background: The evolutionarily conserved protein FBXO9 acts as a substrate receptor for the SKP1-cullin-1-RBX1 ubiquitin ligase and is implicated in cancer, exhibiting either tumor-suppressive or oncogenic effects depending on the specific tumor type. However, their role in lung cancer metastasis remains unclear. Methods: Lentiviral vectors carrying miRNA-based shRNA sequences for gene-specific knockdown were generated, and Lenti-CRISPR-Cas9 vectors containing gene-specific sgRNA sequences were designed. Gene overexpression was achieved using doxycycline-inducible lentiviral constructs, while gene knockdown or knockout cells were generated using shRNA and CRISPR-Cas9, respectively. Functional assays included migration, clonogenic survival assays, tumor sphere assays, and protein interaction studies using mass spectrometry, immunoprecipitation, and immunoblot analysis. Results: This study identified FBXO9 as a crucial regulator that suppresses lung cancer cell migration, tumor sphere growth and restricts metastasis. We showed that FBXO9 facilitates the ubiquitination of the catalytic subunit A (ATP6V1A) of the Vacuolar-type H+-ATPase (V-ATPase), resulting in its interaction with the cytoplasmic chaperone HSPA8 and subsequent sequestration within the cytoplasm. This process hinders the assembly of functional V-ATPase, resulting in reduced vesicular acidification. In contrast, depletion of FBXO9 reduced ATP6V1A ubiquitination, resulting in increased V-ATPase assembly and vesicular acidification, thus promoting pro-metastatic Wnt signaling and metastasis of lung cancer cells. Furthermore, we demonstrated the effectiveness of inhibitors targeting V-ATPase in inhibiting lung cancer metastasis in a mouse model. Finally, we established a correlation between lower FBXO9 levels and poorer survival outcomes in patients with lung cancer. Conclusions: These findings collectively elucidate the critical role of FBXO9 in regulating V-ATPase assembly and provide a molecular basis for FBXO9's function in inhibiting lung cancer metastasis. This highlights the potential therapeutic opportunities of FBXO9 supplementation.

ElecFeX is a user-friendly toolbox for efficient feature extraction from single-cell electrophysiological recordings

Characterizing neurons by their electrophysiological phenotypes is essential for understanding the neural basis of behavioral and cognitive functions. Technological developments have enabled the collection of hundreds of neural recordings; this calls for new tools capable of performing feature extraction efficiently. To address the urgent need for a powerful and accessible tool, we developed ElecFeX, an open-source MATLAB-based toolbox that (1) has an intuitive graphical user interface, (2) provides customizable measurements for a wide range of electrophysiological features, (3) processes large-size datasets effortlessly via batch analysis, and (4) yields formatted output for further analysis. We implemented ElecFeX on a diverse set of neural recordings; demonstrated its functionality, versatility, and efficiency in capturing electrical features; and established its significance in distinguishing neuronal subgroups across brain regions and species. ElecFeX is thus presented as a user-friendly toolbox to benefit the neuroscience community by minimizing the time required for extracting features from their electrophysiological datasets.

A case for using methods from natural science in advancing the field of cognitive neuroscience.

Cognitive neuroscience seeks to pinpoint the neural basis of cognitive function. Application of scientific methods can be credited for its advancement within the field of psychology. Past approaches such as phrenology, that linked bumps on the skull to mental capabilities, initially gained popularity, but the lack of experimental testing contributed to its demise. Research in neuropsychology and the use of the double dissociation experimental technique subsequently emerged. Objective measurements of behaviour following selective damage within the brain led to a paradigm shift. More recently, application of the subtraction technique, coupled with the emergence of cognitive neuroimaging tools, has allowed psychologists to isolate and measure specific functions such as language, vision, memory, and recognition of emotion. Importantly, these approaches enable reliable prediction of behaviours, given parameters of brain integrity, a key goal within the field of psychology.

Quercetin regulates dendritic cell activation by targeting STAT4 in the treatment of experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is a class of autoimmune diseases mainly caused by the immune system attacking the myelin sheath of the axons in the nervous system. Although the pathogenesis of MS is complex, studies have shown that dendritic cells (DCs) play a vital role in the pathogenesis of MS. Quercetin (QU) has a unique advantage in clinical application, especially for treating autoimmune diseases. However, the mechanism of QU in the treatment of experimental autoimmune encephalomyelitis (EAE) remains unclear. In this study, we explore the potential role of QU in EAE. Finally, we find that QU has anti-inflammatory activities and neural protective effects in EAE. The experimental results suggest that the cellular basis for QU's function is to inhibit the activation of DCs while modulating the Th17 cell differentiation in the co-culture system. Further, QU may target STAT4 to inhibit its activation in DCs. This work will be of great significance for the future development and utilization of QU.

Exploring the Conformational Ensembles of Protein-Protein Complex with Transformer-Based Generative Model.

Protein-protein interactions are the basis of many protein functions, and understanding the contact and conformational changes of protein-protein interactions is crucial for linking the protein structure to biological function. Although difficult to detect experimentally, molecular dynamics (MD) simulations are widely used to study the conformational ensembles and dynamics of protein-protein complexes, but there are significant limitations in sampling efficiency and computational costs. In this study, a generative neural network was trained on protein-protein complex conformations obtained from molecular simulations to directly generate novel conformations with physical realism. We demonstrated the use of a deep learning model based on the transformer architecture to explore the conformational ensembles of protein-protein complexes through MD simulations. The results showed that the learned latent space can be used to generate unsampled conformations of protein-protein complexes for obtaining new conformations complementing pre-existing ones, which can be used as an exploratory tool for the analysis and enhancement of molecular simulations of protein-protein complexes.

Enhancing OpenEP: atrial conduction velocity and conduction velocity heterogeneity quantification through EP Workbench

Abstract Background Alterations in atrial conduction velocity have been implicated in the pathogenesis of atrial arrhythmias, with conduction velocity thought to be slower and more heterogeneous in areas promoting atrial fibrillation. However, clinical studies of conduction velocity are challenging since there are no available platforms that provide researchers and clinicians with the ability to quantify conduction velocity and analyse conduction heterogeneity from electroanatomic mapping data. Purpose In this paper we sought to address these limitations by enhancing the OpenEP Python library by (1) automating calculations using previously-published conduction velocity estimation algorithms; (2) providing an interactive graphical representing of conduction velocity and conduction heterogeneity and (3) implementing a histogram analysis tool to quantify conduction velocity and enable the identification of slow conduction regions. Method Two well-known and previously published methods for calculating cardiac conduction velocity, Triangulation and polynomial surface fitting, were implemented. Conduction velocity estimation was improved further by excluding regions with wave collisions and focal discharges. These regions were identified using the divergence of conduction velocity vector fields, with positive divergence representing focal sources and negative divergence representing areas of collision. Finally, calculated conduction velocities using electrogram data were interpolated over the surface mesh via Radial Basis Function (RBF) interpolation method. All algorithms were implemented in the OpenEP Python library (openep-py), with visualisation tools provided in the complementary graphical interface, EP Workbench. Results An extensible "Analysis" feature was created in openep-py, to provide conduction velocity and divergence calculations which are fully customisable through the graphical interface based on user preferences. The EP Workbench desktop application displays resulting cardiac surface maps to depict calculated conduction velocity and divergence fields, together with conventional activation and voltage maps (Figure 1). The histogram analysis tool can be used to identify regions of slow conduction velocity from electroanatomic mapping data. Using a threshold of <0.3m/s, two slow conducting channels are visualised on the posterior wall of a test case (Figure 2). The tool is not specific to conduction velocity and may also be used to quantify other data types in EP Workbench. Finally, computed conduction velocity and divergence values and surface maps are stored in the standard OpenEP data structure, allowing further analysis following data export. Conclusion We have extended OpenEP to provide a comprehensive set of tools for conduction velocity calculation and analysis which will facilitate investigation of the structural and functional basis of conduction velocity alterations in disease states.

Zigzag boron nitride nanotube functionalization as a sensor for the recognition of group IIA (Mg2+, Ca2+) metal ions, quasi-metal (Si2+, Ge2+) ions, and transition metal (Cu2+, Zn2+) ions: a computational study.

Boron nitride nanotubes (BNNTs) provide an exceptional and sophisticated platform for detecting metal ions with high surface area and remarkable chemical stability. Metal cations tend to bind to the surface of BNNTs, which leads to significant changes in the electrical properties of nanotubes. BNNT-based metal ion sensors have shown promising results in various applications, including water quality monitoring, biomedical research, industrial quality control, and environmental monitoring. In the present study, we have explored the electronic sensitivity of the BNNT to metal ions (Si2+, Ge2+, Cu2+, Zn2+, Mg2+, and Ca2+). The interaction between the ions with the pristine BNNT is performed in the solution phase. The results show that ion adsorption on the nanotube surface is exothermic and favorable. The density of states calculation is presented to investigate the electronic properties of the nanotube during the adsorption process. The results display that an increase in the electrical conductivity of the complexes accompanies the reduction in the energy gap. Based on the obtained data, the Si2+ and Ge2+ cations adsorbed on the BNNT with satisfactory Eg changes (%ΔE) can be promising candidates for better sensing ability. All calculations are conducted within the density functional theory (DFT) using the ωB97XD functional and 6-31G(d,p) basis set. The present approach incorporates the utilization of empirical atom-atom dispersion in conjunction with long-range correction. The calculations are performed using the quantum chemistry package GAMESS, and the obtained results are visualized by employing the GaussView 6.0.16 program.

Pengaruh Media Sosial terhadap Politik di Desa Holbung, Kecamatan Sitiotio, Kabupaten Samosir

This research discusses the influence of social media on politics in Holbung Village, Sitiotio District, Samosir Regency. With the emergence and development of information technology, people's behavior has experienced a significant transformation in human thought patterns, feelings and actions. Social media is a potential tool for governments to shape public opinion and influence political participation. In the context of a democratic country like Indonesia, public opinion has a crucial role because it is the basis for government function. This study uses a library study method by collecting data through internet searching and documentation studies. Data analysis techniques include data reduction and data display. The research results show that social media plays a vital role in political participation and the formation of public opinion in the digital era, with both good and bad impacts. Nevertheless, the government needs to monitor political activities in the modern social media era. Social media is not only a communication platform, but also a place for information seeking, discussion and networking. This research aims to analyze how social media shapes political knowledge in society using a qualitative descriptive approach. The research results show that social media has a significant influence in engaging, connecting, and mobilizing political participation, although the receipt of political information via social media may vary between individuals.

The Orthogonal Bases of Exponential Functions Based on Moran-Sierpinski Measures

The Orthogonal Bases of Exponential Functions Based on Moran-Sierpinski Measures

SEC: A core hub during cell fate alteration.

Pol II pause release is a rate-limiting step in gene transcription, influencing various cell fate alterations. Numerous proteins orchestrate Pol II pause release, thereby playing pivotal roles in the intricate process of cellular fate modulation. Super elongation complex (SEC), a large assembly comprising diverse protein components, has garnered attention due to its emerging significance in orchestrating physiological and pathological cellular identity changes by regulating the transcription of crucial genes. Consequently, SEC emerges as a noteworthy functional complex capable of modulating cell fate alterations. Therefore, a comprehensive review is warranted to systematically summarize the core roles of SEC in different types of cell fate alterations. This review focuses on elucidating the current understanding of the structural and functional basis of SEC. Additionally, we discuss the intricate regulatory mechanisms governing SEC in various models of cell fate alteration, encompassing both physiological and pathological contexts. Furthermore, leveraging the existing knowledge of SEC, we propose some insightful directions for future research, aiming to enhance our mechanistic and functional comprehension of SEC within the diverse landscape of cell fate alterations.

ECHOCARDIOGRAPHIC PREDICTORS OF RESIDUAL MR ≥ 2+ AND CLINICAL OUTCOMES ONE YEAR AFTER MITRACLIP IMPLANTATION

Abstract Introduction The extent of residual mitral regurgitation (MR) (1+ vs ≥ 2+) has a notable impact on the outcome of MitraClip (MC) repair of significant functional MR. Aim The aim of the study was to analyze the one–year results in our series of patients with functional MR treated with MC. Materials and Methods Between 2020 and 2022, 58 consecutive patients underwent percutaneous mitral valve repair with MC technology. All patients had moderate–severe MR on a functional basis. Results At one year 10 patients died (mortality 17.2%). The remaining 48 patients had complete follow–up for up to one year and were included in the statistical analysis: The incidence of new hospitalizations was 8.3%; The incidence of grade 1+ and ≥ 2+ MR was 54.1% (26) and 45.9% (22), respectively; In patients with MR ≥ 2+ the clinical and instrumental outcomes were worse than in patients with MR 1+; Posterior leaflet height and extent of immediate postprocedural MR were independent predictors of MR ≥ 2+. In multivariable analysis, preprocedural posterior leaflet height (PLH) (OR 0.16, p = 0.02) and immediate postprocedural MR degree (IPOMR) (OR 12.4, p = 0.03) were predictive; preprocedural Ejection Fraction (EF) was almost significant (OR 0.87, p = 0.08) (Figure 1). Conclusions Percutaneous repair with MC of moderate/severe functional MR has favorable one–year outcomes in terms of mortality and rehospitalizations. The best results are obtained in cases with residual MR 1+. Echocardiographic parameters are independent predictors of residual MR ≥ 2+.

M6A-induced transcription factor IRF5 contributes to the progression of cervical cancer by upregulating PPP6C.

Cervical cancer (CC) is a gynaecological malignancy tumour that seriously threatens women's health. Recent evidence has identified that interferon regulatory factor 5 (IRF5), a nucleoplasm shuttling protein, is a pivotal transcription factor regulating the growth and metastasis of various human tumours. This study aimed to investigate the function and molecular basis of IRF5 in CC development. IRF5, protein phosphatase 6 catalytic subunit (PPP6C) and methyltransferase-like 3 (METTL3) mRNA levels were evaluated by quantitative real-time (qRT)-polymerase chain reaction (PCR). IRF5, PPP6C, METTL3, B-cell lymphoma 2 and Bax protein levels were detected using western blot. Cell proliferation, migration, invasion, angiogenesis and apoptosis were determined by using colony formation, 5-ethynyl-2'-deoxyuridine (EdU), transwell, tube formation assay and flow cytometry assay, respectively. Glucose uptake and lactate production were measured using commercial kits. Xenograft tumour assay in vivo was used to explore the role of IRF5. After JASPAR predication, binding between IRF5 and PPP6C promoter was verified using chromatin immunoprecipitation and dual-luciferase reporter assays. Moreover, the interaction between METTL3 and IRF5 was verified using methylated RNA immunoprecipitation (MeRIP). IRF5, PPP6C and METTL3 were highly expressed in CC tissues and cells. IRF5 silencing significantly inhibited cell proliferation, migration, invasion, angiogenesis and glycolytic metabolism in CC cells, while induced cell apoptosis. Furthermore, the absence of IRF5 hindered tumour growth in vivo. At the molecular level, IRF5 might bind with PPP6C to positively regulate the expression of PPP6C mRNA. Meanwhile, IRF5 was identified as a downstream target of METTL3-mediated m6A modification. METTL3-mediated m6A modification of mRNA might promote CC malignant progression by regulating PPP6C, which might provide a promising therapeutic target for CC treatment.

Dichotomous transactivation domains contribute to growth inhibitory and promotion functions of TAp73

The transcription factor p73, a member of the p53 tumor-suppressor family, regulates cell death and also supports tumorigenesis, although the mechanistic basis for the dichotomous functions is poorly understood. We report here the identification of an alternate transactivation domain (TAD) located at the extreme carboxyl (C) terminus of TAp73β, a commonly expressed p73 isoform. Mutational disruption of this TAD significantly reduced TAp73β's transactivation activity, to a level observed when the amino (N)-TAD that is similar to p53's TAD, is mutated. Mutation of both TADs almost completely abolished TAp73β's transactivation activity. Expression profiling highlighted a unique set of targets involved in extracellular matrix-receptor interaction and focal adhesion regulated by the C-TAD, resulting in FAK phosphorylation, distinct from the N-TAD targets that are common to p53 and are involved in growth inhibition. Interestingly, the C-TAD targets are also regulated by the oncogenic, amino-terminal-deficient DNp73β isoform. Consistently, mutation of C-TAD reduces cellular migration and proliferation. Mechanistically, selective binding of TAp73β to DNAJA1 is required for the transactivation of C-TAD target genes, and silencing DNAJA1 expression abrogated all C-TAD-mediated effects. Taken together, our results provide a mechanistic basis for the dichotomous functions of TAp73 in the regulation of cellular growth through its distinct TADs.

On Itskov (2024) counterexample to the functional basis of isotropic vector and tensor functions by Shariff (2023)

On Itskov (2024) counterexample to the functional basis of isotropic vector and tensor functions by Shariff (2023)

Analysis of landscape pattern and ecological risk change characteristics in Bosten Lake basin based on optimal scale

Amidst swift socioeconomic progress, urbanization is intensifying, necessitating robust methodologies for environmental quality monitoring. Landscape Ecological Risk (LER) has emerged as a pivotal tool in this context. Extensive research has focused on the land utilization rates within watersheds, scrutinizing them through the lens of land use/land cover (LULC) dynamics. This study delves into the LULC attributes of the Bosten Lake Basin (BLB) across three temporal snapshots: 2000, 2010, and 2020. Grasslands and bare ground made up the vast majority area of the BLB. Selected twelve landscape pattern indices, analyzed their response curves with respect to grain size, determined the optimal grain size to be 150 m, and analysed its optimum amplitude of 10 km × 10 km on the basis of the semi-variance function, thus determined the optimal scale for analyzing the landscape pattern. Exploring scale effect facilitates a nuanced examination of the landscape patterns and land use efficacy within BLB. From 2000 to 2020, the landscape pattern showed less fragmented, less aggregated, and more spatially heterogeneous. The landscape ecological risk index model has been constructed for the investigation of the LER change characteristics of the BLB. Lowest-risk zones and lower-risk zones of LER predominate in BLB. In 2000, 2010 and 2020 the combined lower and lowest risk zones represent 62.02 %, 59.37 % and 58.44 % of the catchment area respectively. Finally, analyzed the spatial autocorrelation variation characteristics of LER. The global Moran' I index of BLB for the three periods from 2000 to 2020 exceeded 0.7. This study establishes theoretical and practical foundation for future multi-scale landscape ecological risk studies in eco-fragile regions.

Corn protein hydrolysate with glutamine-rich peptides protects intestinal barrier in Caco-2 cells: Insights into structural characteristics of identified glutamine peptides

Intestinal barrier is an important basis for intestinal function, which can strictly control the exchange of substances between the host and the external environment. An intact intestianl barrier is also the guardian of human health. In this study, the protective effect of corn protein hydrolysate with glutamine-rich peptides (APH) on intestinal epithelial cell barrier was evaluated in Caco-2 cell inflammatory damage model induced by lipopolysaccharide (LPS). Then, the sequences of glutamine peptides in APH were identified by Nano LC-MS/MS, and the structural characteristics of the identified glutamine peptides were analyzed. The results showed that the hydrolysate effectively alleviated LPS-induced cell damage and decreased the inflammatory response by down-regulating the levels of pro-inflammatory cytokines (TNF-α, IL-8, and IL-1β) and up-regulating the levels of anti-inflammatory cytokine (IL-10). Moreover, the hydrolysate also up-regulated the gene expression of three tight junction proteins (ZO-1, Occludin, Claudin-1) to maintain the integrity of the intestinal epithelial barrier. More importantly, the hydrolysate protected the intestinal barrier function via down-regulating the key genes expression (TLR4, MyD88, NF-κB) in the NF-κB signaling pathway and inhibiting the overexpression of MLCK gene in the MLCK signaling pathway. Finally, 374 corn glutamine peptides were identified from APH, and their structural characteristics showed that corn glutamine peptides had high affinity with membrane proteins. Taken together, these results indicated that APH has excellent potential to protect intestinal barrier function and can be developed into a functional health food.