From bacterial killing to immune modulation: Recent insights into the functions of lysozyme

Diclofenac Immune-Mediated Hepatitis: Identification of Innate and Adaptive Immune Responses at Clinically Relevant Doses

Diclofenac is an effective medication for pain and inflammation. However, its use has been linked to hepatitis. To gain insight into diclofenac's ability to cause hepatitis, we investigated the regulation of major effectors of the immune system following daily treatment of minipigs at 3 and 15 mg/kg for 28 days. Histopathology evidenced lobular inflammation, and through a combination of immunogenomics and immunopathology, we detected marked innate and adaptive immune responses. We identified 109 significantly regulated genes linked to neutrophil, monocyte, Kupffer cell, and lymphocyte responses and 32 code for cytokine- and interferon-γ-signaling. In support of wound repair, immunopathology evidenced manifest upregulation of macrophage migration inhibitory factor and CD74. Furthermore, the strong expression of IgG and IgM underscored humoral immune responses. Diclofenac caused an activation of the complement system, especially the C1 inhibitor of the classical pathway and C3 with critical functions in liver regeneration. The marked expression of complement factor B and H of the alternate pathway modulated B-cell responses. Likely, the upregulation of factor H protected hepatocytes from injury by limiting complement-mediated damage of inflamed cells. Additionally, diclofenac treatment elicited marked hepatic expression of lysozyme and KLF6. The latter earmarks M1-polarized Kupffer cells. We observed an extraordinary induction of calprotectin/S100A9 and of the monocyte/macrophage CD163 scavenger receptor, and therefore, we detected innate immune sensing of damaged cells. Lastly, we noted an unprecedented induction of the acute phase reactant SAA1 and DEC-205, which recognize apoptotic and necrotic cells. Together, our results offer mechanistic insights into immune-mediated liver injury patterns following diclofenac treatment.

Simulating the activity of the natural antimicrobial system of milk on the growth of selected cultures involved in cheesemaking and ripening

The impact of three antimicrobial proteins (lactoferrin, lactoperoxidase, lysozyme) on the growth of cultures involved in cheesemaking and ripening was studied. Strains were grown in the optimal media growth of each strain or in cheese simulated environment. The media were supplemented with the antimicrobial proteins together (MIX; 1:1:1) or individually at concentrations found in milk (1x) and cheese (2.5x). Growth properties were evaluated using a novel approach by combining flow cytometry and spectrophotometric assay. Flow cytometry measures cell viability (live/injured/dead cells; total cells). Lactococcus cremoris CUC-C (starter culture) was stimulated by lactoperoxidase and lysozyme reaching higher optical density and total cells than control (without antimicrobial proteins). In cheese simulated environment, the live cells of L. cremoris CUC-C increased of more than 30% in the MIX condition without an increase in total cells. Flow cytometry allowed to show this protective effect. For cultures involved in ripening, the total cells of Lactiplantibacillus plantarum ATCC 14917 and Lacticaseibacillus paracasei subsp. tolerans LMA-1802 decreased of 1 log in the MIX condition. Although the same log reduction, different inhibition behavior was observed. Live cells for Lpb. plantarum ATCC 14917 remained unchanged while for Lcb. paracasei LMA-1802, injured cells increased. These observations were only possible by flow cytometry. The higher concentration (2.5x) tended to decrease the growth properties (lower maximal rate, longer lag phase) of strains as compared to the lower one (1x). The strain-dependent sensitivity to the three antimicrobial proteins underlines the importance of evaluating their effect on cultures prior cheesemaking to ensure proper functionality.

Micro/nanorobots in antimicrobial therapy: Addressing challenges of antibiotic resistance

Antibiotic resistance has emerged as a critical global health challenge, particularly when bacteria form biofilms that render conventional antimicrobial treatments markedly less effective. Bacteria residing within biofilm exhibit increased resistance to antimicrobial agents and host immune defenses, complicating treatment and contributing to recurrent infections. Antimicrobial micro- and nanorobots (MNRs) have garnered significant attention as a promising strategy to combat drug-resistant bacteria and biofilms, owing to their exceptional motility, precise targeting, and improved penetration capabilities. Despite their potential, challenges related to biocompatibility, imaging integration, and clinical translation remain unresolved. This review summarizes the latest developments in the therapy of micro/nanorobots for antimicrobial therapy, emphasizing innovative strategies for bacterial eradication and biofilm disruption while addressing the technical hurdles and exploring future research directions.

Gut Microbiota Modulation by Lysozyme as a Key Regulator of Vascular Inflammatory Aging

Vascular inflammatory aging is strongly associated with multimorbidity, including immunosenescence. Here, bioinformatic analysis indicated elevated expression of the lysozyme (LYZ) gene in age-dependent vascular diseases. Lyz1 deficiency led to vascular inflammatory aging, including damage to indicators related to oxidative stress, vascular function, and inflammation in the serum and vascular tissues of wild-type (WT) and Lyz1-/- mice. The 16S ribosomal RNA sequencing of intestinal contents revealed increased Bifidobacterium and its metabolism of acetate, butyrate, omega-muricholic acid, propionate, and valeric acid in Lyz1-/- mice compared with that in WT mice. Additionally, RNA sequencing of vascular tissues identified differentially expressed genes in Lyz1-/- mice compared with those in WT mice, as well as enrichment of the common phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway. Vascular inflammatory aging phenotypes were detected in the blood vessels of antibiotic-treated and germ-free mice, and the PI3K-Akt signaling pathway was inhibited. Importantly, intravenous LYZ administration worsened the pathological conditions, whereas oral LYZ administration successfully restored the gut microbial balance and reversed the vascular inflammatory aging phenotypes. Collectively, this study establishes LYZ as a novel biomarker for age-related vascular diseases and the gut microbiota-PI3K-Akt axis as a promising therapeutic target.

Innovative vibriosis control in open aquaculture: Paratapes undulata as a sustainable growth and resistance enhancer in red tilapia

This study demonstrates the novel therapeutic potential of Paratapes undulata for mitigating Vibrio alginolyticus infection in red tilapia. In vivo, P. undulata significantly improved growth by approximately 362% in group G3 (Clam-treated Control) and 284% in group G4 (Clam-treated Infected), compared to the infected control group (G2), and reduced mortality by 100% in group G3 and 75% in group G4, compared to the infected control group (G2), and alleviated clinical signs, correlating with enhanced hematological and biochemical profiles, and reduced tissue damage. Mechanistically, P. undulata modulated the immune response by shifting cytokine balance towards anti-inflammation, enhanced antioxidant capacity, and directly inhibited Vibrio alginolyticus virulence. Gas Chromatography-Mass Spectrometry and Fourier-Transform Infrared Spectroscopy analyses revealed the presence of bioactive compounds contributing to these effects. These findings establish P. undulata as a promising, natural, and sustainable biocontrol agent for vibriosis in aquaculture, offering a novel strategy for disease management and reducing reliance on antibiotics. This study suggests that P. undulata can be effectively incorporated into aquaculture feed or water treatments to prevent and manage vibriosis outbreaks.

Novel Delivery of Cyclic-Diguanylate Monophosphate Utilizing Amyloid Depots

Background: Recently, cyclic diguanylate monophosphate (c-di-GMP) drug delivery has garnered interest due to its potential in cancer immune modulation. In this pilot study, we developed a novel c-di-GMP formulation based on peptide amyloids. The amyloid depots were formed by combining an amyloidogenic prone 12 amino acid peptide sequence of receptor-interacting protein kinase 3 (RIP3) with cationic lipid ALC-0315, or using lysozyme proteins. Both RIP3 and lysozyme proteins have intrinsic physiological functions. This is the first time intrinsic peptides/protein-based amyloids have been explored for c-di-GMP delivery. The main goal was to evaluate how these amyloid depots could enhance c-di-GMP drug delivery and modulate responses in RAW 264.7 macrophage-like cells. Methods: Physicochemical characterization and cellular assays were utilized to characterize the amyloid structures and assess the efficacy. Results: Our results show that amyloid aggregates significantly improve the therapeutic efficacy of c-di-GMP. When RAW 264.7 cells were treated with c-di-GMP amyloids, we observed at least a 1.5-fold change in IL-6 expression, nitric oxide (NO) production, and reactive oxygen species (ROS) production compared to treatment with 5x free c-di-GMP treatment, which suggests that this system holds promise for enhanced therapeutic effects. Conclusions: Overall, these findings emphasize the potential of amyloid-based delivery systems as a promising approach for c-di-GMP delivery, warranting further investigations into their potential in therapeutic applications.

Binding of potential antitumor Casiopeínas® to small proteins

Casiopeínas® are a family of patented CuII anticancer compounds. Cas II-gly and Cas VII-gly are formed by 4,7-dimethyl-1,10-phenanthroline (Me2phen) and 1,10-phenanthroline (phen), respectively, and the bidentate glycinato ligand (Gly), along with a nitrate anion acting as a counterion. In biological fluids, they can maintain their identity or form mixed species and adducts with several bioligands, particularly proteins. In this study, the binding of Cas II-gly, and, for comparison, Cas VII-gly, to small proteins such as myoglobin (Mb), ubiquitin (Ub), and lysozyme (Lyz) was evaluated through a combination of instrumental (ESI-MS and EPR) and computational (dockings) methods. Simulations of the peak signals in the ESI-MS spectra confirmed the formation of the adducts. The results indicated that in all systems, adducts with the formula protein-[CuII(Me2phen)]n (with n = 1-3) were formed after the replacement of glycinato in the equatorial positions by side-chain donors. Docking studies showed that the three proteins used different donor sets to bind the CuII(Me2phen)2+ fragment: (NHis, NHis) or (NHis, COO-Asp/Glu) for Mb; NHis68 or (COO-Glu/Asp, COO-Glu/Asp) for Ub; and (COO-Glu/Asp, CO) or only a monodentate O donor for Lyz. Computational exploration of the protein structure revealed that more than one metal fragment could bind to the macromolecule. At present, it is not clear whether the formation of the adducts improves or worsens the activity of Casiopeínas®. However, the results suggested that, at the low copper concentrations found in the organism, the species protein-[CuII(Me2phen)]n coexist with [CuII(Me2phen)(Gly)]+ and the fragment CuII(Me2phen)2+, which - in turn - could partially dissociate into Cu2+ ions and free Me2phen ligands. Therefore, a mixture of species could be responsible for the biological activity of Casiopeínas®.

Simple and hybrid materials for antimicrobial applications

Simple and hybrid materials represent alternatives to traditional antibiotics in the ongoing effort to combat the growing issue of antibiotic-resistant bacterial strains, which have emerged due to the misuse of antibiotic treatments and improper disposal of antibiotic-related waste. First, after outlining the scale of the issue, multiple potential agents that may help address the problem are presented. Inorganic metal-based and metal oxide-based nanomaterials such as silver, gold, gallium, zinc/zinc oxide, copper/copper oxide, titanium dioxide, and magnesium oxide nanoparticles are characterized, their synthesis is described, and examples of their potential antimicrobial applications are provided. Subsequent sections in a similar vein, explore nonmetallic inorganic nanoparticles and characterize organic materials that may function either as antimicrobial agents themselves (e.g., antimicrobial peptides, chitosan) or as structural components and drug carriers (e.g., cellulose, SNLs, liposomes). The final chapter offers examples of combining inorganic and organic materials into hybrid solutions for specialized antimicrobial applications and treatments, aiming to enhance their inherent antimicrobial properties or reduce the required dosage of antibiotics in therapy.

Integrated analysis of single-cell RNA-seq and bulk RNA-seq unravels the molecular feature of tumor-associated neutrophils of head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a lethal malignancy with a high recurrence and distant metastasis rate, posing significant challenges to patient prognosis. Recent studies suggest that tumor-associated neutrophils (TANs) can modulate immune cell infiltration and influence tumor initiation and progression. However, the potential clinical significance of TANs in HNSCC remains insufficiently explored.

METHODS

TANs-specific marker genes were identified via single-cell sequencing data from HNSCC. Based on data from The Cancer Genome Atlas (TCGA), a prognostic risk model was constructed using TANs cell marker genes, and the model was validated with data from the Gene Expression Omnibus (GEO) database. The associations between the TANs signature and clinical characteristics, functional pathways, immune cell infiltration, immune checkpoint expression, and responses to immunotherapy and chemotherapy, were then investigated. Cell counting kit-8(CCK-8), Transwell, and wound healing assays were conducted to assess the functional role of TANs marker molecules.

RESULTS

TANs characteristic genes were identified from single-cell sequencing data from HNSCC patients. On the basis of these characteristic genes, a tumor-associated neutrophils-associated signature (NRS) was developed and validated across internal and external cross-platform cohorts through comprehensive procedures. The NRS demonstrated robust and reliable performance in predicting overall survival. Additionally, patients with a low NRS showed enhanced immune cell infiltration, active lipid metabolism, and increased sensitivity to immunotherapy. In contrast, patients with a high NRS exhibited poor prognostic outcomes, advanced clinical stages, and significant associations with HNSCC metastasis and progression. Furthermore, we identified a TANs-associated biomarker, OLR1, and validated that OLR1 promotes HNSCC proliferation, invasion, and migration through CCK-8, Transwell invasion, and wound healing assays.

CONCLUSION

This study has developed a promising TANs-based tool that may aid in personalized treatment and prognostic management for patients with HNSCC.

Strategies for enhancing the antibacterial efficacy of lysozyme and the resulting outcome

Lysozyme is a biological macromolecule with potent bactericidal activity, providing a foundation for its use as a natural preservative. It was extensively applicated in the food and pharmaceutical industries, where its active properties are harnessed effectively and sustainably. However, the effect of natural lysozyme on individual gram-positive bacteria and most gram-negative bacteria is not ideal. At present, some antibacterial profiles of extended lysozyme have been developed. With the recent advancements in biotechnology, there has been a notable increase in the potential of methods and techniques for modifying protein enzymes. This paper mainly introduces the basic structural properties of natural hen egg white lysozyme, its bactericidal properties, and mode of action, and focuses on the comparison of different methods and strategies for lysozyme modification at present, including differential isomerization of lysozyme, surface hydrophobicity modification, chemical modification and combination, and influence on lysozyme properties. These findings emphasize that the key to augmenting lysozyme's efficacy lies in manipulating charge, ion characteristics, and modifying active amino acid groups to optimize interactions with bacterial cell walls and membranes, facilitating bacterial autolysis. By applying these principles, it can lay a solid foundation for developing more effective and versatile protein-based lysozyme antibacterial agents.

Identifying disease progression biomarkers in metabolic associated steatotic liver disease (MASLD) through weighted gene co-expression network analysis and machine learning

BACKGROUND

Metabolic Associated Steatotic Liver Disease (MASLD), encompassing conditions simple liver steatosis (MAFL) and metabolic associated steatohepatitis (MASH), is the most prevalent chronic liver disease. Currently, the management of MASLD is impeded by the lack of reliable diagnostic biomarkers and effective therapeutic strategies.

METHODS

We analyzed eight independent clinical MASLD datasets from the GEO database. Differential expression and weighted gene co-expression network analyses (WGCNA) were used to identify 23 genes related to inflammation. Five hub genes were selected using machine learning techniques (SVM-RFE, LASSO, and RandomForest) combined with a literature review. Nomograms were created to predict MASLD incidence, and the diagnostic potential of the hub genes was evaluated through receiver operating characteristic (ROC) curves. Additionally, Protein-Protein Interaction (PPI) networks, functional enrichment, and immune infiltration analyses were performed. Potential transcription factors and therapeutic agents were also explored. Finally, the expression and biological significance of these hub genes were validated using MASLD animal model, histological examination and transcriptomic profiles.

RESULTS

We identified five hub genes-UBD/FAT10, STMN2, LYZ, DUSP8, and GPR88-that are potential biomarkers for MASLD. These genes exhibited strong diagnostic potential, either individually or in combination.

CONCLUSION

This study highlights five key biomarkers as promising candidates for understanding MASLD. These findings offer new insights into the disease's pathophysiology and may contribute to the development of better diagnostic and therapeutic approaches.

Biocompatible OFETs for Selective and Real-Time Bacterial Detection Using BSA and Lysozyme Layers

In the realms of modern medicine and environmental monitoring, there is an escalating demand for bacterial detection technologies that are rapid, precise, and highly sensitive. Conventional methods, however, are often hindered by their time-intensive nature, procedural complexity, and reliance on specialized laboratory equipment. This study introduces an innovative approach utilizing bovine serum albumin (BSA) as the dielectric layer and lysozyme (LYZ) as the bacterial sensing layer in organic field-effect transistors (OFETs). The combination of BSA and LYZ enhances both biocompatibility and detection sensitivity, enabling precise differentiation between Gram-positive and Gram-negative bacteria. BSA not only stabilizes the electrical performance of the OFET but also offers biodegradability and water solubility, contributing to environmental sustainability. These biocompatible OFETs can accurately detect bacterial concentrations ranging from 104 to 108 CFU/mL, with real-time response capabilities via multispike measurements. This research represents a significant step forward in the development of advanced, portable biosensors for use in complex biological environments, advancing bacterial detection technology.

Lysozyme modulates inflammatory responses to exacerbate the severity of rheumatoid arthritis

BACKGROUND

The mechanisms underlying Rheumatoid Arthritis (RA) remain unclear. Despite having relatively well-defined treatment strategies, current therapeutic approaches only achieve a remission rate of 70 %-80 %, with poor prognosis and no clear diagnostic criteria for early RA. Therefore, there is a need for new therapeutic targets or biomarkers to improve the treatment of RA.

METHODS

Firstly, we identified the expression characteristics of lysozyme (LYZ) in early RA patients through plasma proteomics and synovial fluid single-cell sequencing analysis. Secondly, we constructed Lyz1 cKO mice to investigate the role of Lyz1 in RA pathogenesis using the Collagen Antibody-Induced Arthritis (CAIA) mouse model. Thirdly, we silenced LYZ to clarify its impact on TNF-α-induced inflammatory cytokine release and other inflammatory phenotypes in MH7A cells. Finally, we explored the cellular pathways involving LYZ in fibroblast-like synoviocytes (FLSs) and changes in RA-related genes through RNA sequencing (RNA-Seq).

RESULTS

LYZ was highly expressed in the plasma and synovial macrophages of early RA patients. The absence of Lyz1 reduced the arthritis course and joint damage in CAIA mice. Silencing LYZ promoted the proliferation and apoptosis of MH7A cells and improved their inflammatory phenotypes, possibly through the regulation of the TNF signaling pathway.

CONCLUSION

LYZ is highly expressed in the plasma and synovial fluid macrophages of early RA patients and exacerbates RA progression by modulating inflammation-related pathways, demonstrating potential as a biomarker for early RA diagnosis or a therapeutic target.

Evaluation of the combined impact of aflatoxin B1 and deoxynivalenol fed to Penaeus vannamei and mitigation properties provided by a yeast cell wall extract

The purpose of this study was to examine how white shrimp (Penaeus vannamei) responded to varying concentrations of combined mycotoxins (aflatoxin B1 (AFB1) and deoxynivalenol (DON)) as well as the mitigating effects of an adsorbent (yeast cell wall extract, YCWE). The experiment comprised of five groups receiving isonitrogenous and isolipidic diets: CON (control group), LDA (CON with 20 μg/kg AFB1 and 1500 μg/kg DON), HDA (CON with 100 μg/kg AFB1 and 3000 μg/kg DON), LDAM (LDA with 0.2 % YCWE), and HDAM (HDA with 0.2 % YCWE). Results showed that the contents of total protein, total cholesterol, hemocyanin, and enzyme activities (e.g., catalase, phenoloxidase) in plasma were lower in HDA group, while the alanine aminotransferase activity and malondialdehyde content were higher. The HDA group showed up-regulated expression of apoptotic genes in the hepatopancreas but down-regulated expression of immune-related and antioxidant genes. In the LDA and HDA groups, the higher expression of inflammatory genes in hepatopancreas, the lowest chewiness of muscle and the higher abundance of potential pathogens (e.g., Escherichia-Shigella) in the intestine were observed. However, LDAM and HDAM diets were able to enhance the immune response, antioxidant capacity, and hepatopancreatic and intestinal health of shrimp, especially increased the abundance of intestinal bacteria for detoxification (e.g., Pseudomonas). Moreover, dietary YCWE also led to significantly greater mycotoxin content in the feces. In conclusion, the combined mycotoxins AFB1 and DON can negatively affect the health of shrimp, even at lower doses. But adding YCWE to the diets can effectively mitigate these negative effects.

Cell membrane-derived nanovesicles as extracellular vesicle-mimetics in wound healing

Cell membrane-derived nanovesicles (NVs) have emerged as promising alternatives to extracellular vesicles (EVs) for wound healing applications, addressing the limitations of traditional EVs, which include insufficient targeting capability, low production yield, and limited drug-loading capacity. Through mechanical cell extrusion methods, NVs exhibit superior characteristics, demonstrating enhanced yield, stability, and purity compared to natural EVs. These NVs can be derived from various membrane sources, including single cell types (stem cells, blood cells, immune cells, and bacterial membranes), hybrid cell membranes and cell membranes mixed with liposomes, with each offering unique therapeutic properties. The integration of genetic engineering and surface modifications has further enhanced NV functionality, enabling precise targeting and improved drug delivery capabilities. Recent advances in NV-based therapies have demonstrated their potential across multiple biomedical applications. Although challenges persist in terms of standardization, storage stability, and clinical translation, the combination of natural cell-derived functions with artificial modification potential positions NVs as a promising platform for next-generation therapeutic delivery systems, thereby offering new possibilities in wound healing applications. Finally, we explore the challenges and future prospects of translating NV-based therapeutics into clinical practice, providing insights into the future development of this innovative approach in wound healing and tissue repair.

Nigella sativa monophosphoryl lipid A nanoliposome: a promising antibiotic alternative and immunomodulator to control virulent pandemic drug-resistant Salmonella pullorum infection in broiler chicks

BACKGROUND

Salmonella enterica serovar Pullorum, the causative agent of pullorum disease, is one cause of the economic losses in the global poultry industry. Vaccination and antibiotics are still the most effective methods of controlling Salmonella, even though the vaccine contains the causative agent, and the antibiotic therapy has limited efficacy. We provide a novel immunostimulator and antibiotic substitute to protect against and avoid Salmonella pullorum (SP) infection.

METHODS

Nigella sativa-purified oil (NS) and monophosphoryl lipid A (MPLA) were formulated as nanoliposomal compounds (NS-MPLA). Their protective and immunomodulatory efficacies were experimentally tested orally in broiler chicks against challenge with virulent pandemic drug-resistant SP. Four chick groups were utilized: control; NS-MPLA-supplemented; SP-challenged; and SP-challenged, then NS-MPLA-treated. Clinical signs, organ gross pathology, colony-forming counts, and tissue histopathological alterations were investigated. The relative fold-changes in the expression of IL-1β, IL-4, IL-17, IL-22, TLR-4, INF-γ, IgA, and MUC2 genes were evaluated.

RESULTS

The SP-challenged chicks showed notable symptoms and extensive pathological lesions in their internal organs. The bacteria colonized the challenged chicks' livers and continued to shed in their feces for 5-6 days. A minor amount of immune cell tissue trafficking was noted. The NS-MPLA-treated chicks displayed opposing patterns after being challenged with SP. They exhibited mild clinical signs with modest gross pathology in the internal organs. After 3-4 days, the liver and the fecal droppings were cleared of SP. Significant heterophilic aggregation, lymphocytic infiltration, and lymphoid follicle enlargement were observed. Additionally, chicks challenged with SP and then NS-MPLA-treated showed a 5- to tenfold increase in immune-related cytokines, immunoglobulin A, and mucosal relative gene expression folds compared to the SP-challenged non-NS-MPLA-treated, which showed a sharp decline in IL-4 and IL-22 and a minor rise in the rest of the tested gene relative expressions. Chicks given NS-MPLA supplementation showed a significant upregulation of these genes compared to the control group.

CONCLUSION

In this first report on poultry, it is possible to draw the conclusion that NS-MPLA supplementation in SP-infected chicks boosts immunity and provides protection. It promoted bacterial clearance and tissue repair and stimulated the expression of genes linked to immunity and the mucosal surface. These findings suggest the potential application of NS-MPLA in salmonella control programs as an antibiotic substitute or in immunization strategies.

Molecular characterization of two newly recognized lysozymes of the protist Dictyostelium discoideum

The model organism Dictyostelium discoideum functions as a social amoeba that can aggregate, eventually forming a fruiting body composed of a fixed number of cells. This behavior requires a soluble counting factor (CF) complex, which plays a key role in group size determination and has been identified earlier. The CF complex comprises among others the proteins CF45-1 and CF50. Although both proteins share sequence similarities with characterized Chalaropsis- and Entamoeba-type lysozymes, enzymatic activity has not been confirmed until now. CF lysozymes have unusual sequence characteristics consisting of an N-terminal glycoside hydrolase family 25 (GH25) domain and a C-terminal low-complexity region rich in serine, glycine, alanine, and asparagine residues. In this study, we present the production and purification of soluble recombinant CF lysozymes and demonstrate notable enzymatic activity, in particular for CF50. Additionally, a truncated version of CF50, which lacks the C-terminal low-complexity region, displayed significantly enhanced lysozyme activity compared to the entire enzyme. Both CF lysozymes exerted strict pH dependence with maximal activity observed under acidic conditions at pH 3.0-3.5. Moreover, the enzymes displayed highest activity at low ionic strengths and were stable at relatively low temperatures only. Using structural modeling and site-directed mutagenesis, we identified a glutamic acid residue essential for catalysis. Conclusively, we propose a neighboring group catalytic mechanism analogous to that of other GH25 lysozymes.

Molecular insights into septin 2 protein in rohu (Labeo rohita): revealing expression dynamics, antimicrobial activity and functional characteristics

Septins are evolutionarily conserved GTP-binding proteins mediating innate immunity, autophagy and inflammation in higher animals; however, they are yet to be fully characterized in fish. The study encompasses cloning of complete septin 2 cDNA from the rohu carp (Labeo rohita) that consisted of an open reading frame of 1050 bp and phylogenetic amino acid similarity of 99.43 % to cyprinid Onychostoma macrolepis. Septin 2 was ubiquitously expressed in different tissues of healthy rohu, and during early developmental stages. Septin 2 transcript levels were increased in response to three infection models i.e. Aeromonas hydrophila, poly I:C, and Argulus siamensis, indicating its role in immunity. A synthetic antimicrobial peptide derived from the septin 2 gene revealed in vitro bactericidal activity. A produced recombinant protein of septin 2 (~40 kDa) when injected into rohu modulated the expression of various immune-related genes. Further, in vivo studies of this protein demonstrated protection against A. hydrophila (71 % relative percent survival) and delayed mortality against ectoparasite A. siamensis. A developed sandwich ELISA revealed enhanced septin 2 level post A. hydrophila infection. The present study provides a new understanding of the septin 2 gene's multifunctional role in rohu and its importance in fish antimicrobial defence.

Lysozyme/Tracheal Antimicrobial Peptide-Based Tissue-Specific Expression Antimicrobial Plasmids Show Broad-Spectrum Antibacterial Activities in the Treatment of Mastitis in Mice

The use of antibiotics is the preferred therapy for bacterial diseases. However, overusing antibiotics has led to the development of antibiotic resistance in bacteria, which is now a major public health concern. Therefore, in this study, the performance of lysozyme (LYZ)/tracheal antimicrobial peptide (TAP)-based tissue-specific expression antimicrobial plasmids (TSEAP) have been evaluated in the treatment of mastitis in mice. The results show that LYZ/ and TAP-based TSEAP could effectively reduce the clinical symptoms caused by Staphylococcus sciuri, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa-induced mastitis. In addition, the studies of behavioral tests, parameters of weight growth, blood biochemistry, and organ coefficients comprehensively indicate that the transfection of LYZ/TAP-based TSEAP is safe in mice. Taken together, LYZ/TAP-based TSEAP have broad-spectrum antibacterial activity and may provide new insight for the non-antibiotic treatment of bacterial diseases.

NIR light-driven nanomotor with cascade photodynamic therapy for MRSA biofilm eradication and diabetic wound healing

Background: Diabetic wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) are challenging to heal due to biofilm formation, which impairs conventional antibiotics with limited penetration and severe side effects. Near-infrared (NIR)-driven nanomotors with autonomous motion and photothermal effects show promise for antibacterial therapy but often lack targeted specificity. Lysostaphin (Ly), an enzyme targeting bacterial cell walls, offers excellent potential against drug-resistant MRSA. Methods: A novel NIR-driven CSIL nanomotor has fabricated by co-loading indocyanine green (ICG) and lysostaphin onto spinous yolk-shell structured C/SiO2@C nanoparticles. The autonomous motion, biofilm penetration, and antibacterial efficacy of CSIL nanomotors are evaluated in vitro, while their biofilm eradication and wound healing performance are assessed in an MRSA-infected diabetic mouse model using a cascade photodynamic therapy (CPDT) strategy. Results: CSIL nanomotors exhibit photothermal and photodynamic properties with MRSA-targeting specificity. They can effectively eradicate MRSA biofilms both in vitro and in vivo, suppress virulence and biofilm-related genes, thus promoting diabetic wound healing by shaping a microenvironment dominated by M2 macrophages. The CPDT strategy is able to avoid excessive ROS production and thermal damage, enabling safe and effective therapy. Conclusion: CSIL nanomotors, with integrated photothermal, photodynamic, and MRSA-targeting properties, represent a novel, efficient and targeted approach to antibacterial therapy in diabetic wounds, offering significant advantages over conventional antibiotics.

Effects of Brown Algae (Laminaria japonica) Extract on Growth Performance, Immune Function and Intestinal Health of Largemouth Bass (Micropterus salmoides)

This study used largemouth bass (initial average weight: 33.33 ± 1.8 g) to explore the effects of adding different brown algae extracts to feed on the fish's growth, immunity and intestinal health. Six groups were set up: a control (Group A), 0.1% sodium alginate (Group B), 0.1% oligotriosaccharide I (Group C), 0.1% oligotriosaccharide II (Group D), 0.2% brown algae powder (Group E) and 0.2% brown algae powder enzymatic product (Group F), with three replicates of 35 fish each, and a 56-day feeding experiment. Results: Compared to Group A, Groups C, D and F had a higher specific growth rate and lower feed coefficient (p < 0.05). Group D had enhanced serum SOD activity; Group F had increased antioxidant enzyme activity and decreased MDA content (p < 0.05). All experimental groups had higher serum LZM levels (p < 0.05), with no IgM difference (p > 0.05). In the intestine, treatment groups had higher α-amylase activity (p < 0.05) and no lipase difference (p > 0.05), and Groups C, D and F had higher trypsin activity (p < 0.05). Group F had the tallest villi, Group B had the thickest muscular layer (p < 0.05), and villus width was similar among groups (p > 0.05). The experimental groups had fewer intestinal pathogenic bacteria, and Group F had improved intestinal microorganism diversity and richness (p < 0.05). In conclusion, adding 0.1% oligotriosaccharide and 0.2% brown algae powder enzymatic product to feed can promote largemouth bass growth, antioxidant capacity and immunity. The 0.2% brown algae powder enzymatic product is better for intestinal development and flora improvement.

Human milk as a complex natural product

Covering: up to the end of 2024Breastfeeding is one of the most effective ways to promote child health. However, characterizing the chemistry that fortifies the benefits of breastfeeding remains a grand challenge. Current efforts in the community are focused on characterizing the roles of the different carbohydrates, proteins, and fats in milk. The goal of this review is to highlight and describe current knowledge about the major classes of macromolecules in human milk and their potential role in infant health and wellness.

Impact of Bambusa vulgaris-supplemented diet on Nile tilapia challenged with Pseudomonas putida: Hematological, immune, and oxidative responses

This study investigated the effects of bamboo shoot extract (Bambusa vulgaris) as a feed additive on the health profiles and infection resistance of Nile tilapia (Oreochromis niloticus) against Pseudomonas putida. Bamboo shoot extract was added at levels of 0 g, 40 g, and 60 g per 1000 g of diet over a 60-day period. The fish were then challenged with a pathogenic P. putida strain. Chemical analysis of the bamboo shoot extract identified 3,5-dinitrophenol and hydroquinone as the two most abundant compounds. Results showed that fish fed bamboo-enriched diets exhibited significantly enhanced levels of red blood cells, hemoglobin, hematocrit, white blood cells, and platelets, and improved erythrocyte cellular and nuclear morphologies, indicating improved health profiles after the challenge. Liver function indicators, including AST, ALT, and ALP, were notably balanced in fish receiving bamboo shoot extract post-challenge (p < 0.05). Blood levels of K+ were lower in the bamboo-fed groups. Additionally, blood levels of Ca++ and Na+ were reduced in fish fed 40 g and 60 g of bamboo, respectively, compared to the control group (p < 0.01). The bamboo extract also enhanced immune and oxidative capacities, as demonstrated by increased catalase, superoxide dismutase, lysozyme activity, and phagocytic activity, along with reduced malondialdehyde levels and elevated serum immunoglobulin M (p < 0.01). Gene expression analysis revealed significant effects of Bambusa vulgaris extract, Pseudomonas infection, and their interaction on the expression of interleukin-1β, interleukin-10, and NK-lysin genes, with varying expression levels at 1, 3, and 7 days post-challenge (p < 0.05). The liver bacterial load in fish exposed to P. putida significantly decreased in the bamboo-fed groups, with the lowest count observed in the 60 g bamboo group. Additionally, survival rates were markedly higher in the bamboo-fed groups compared to the control, with no significant difference between the two bamboo-fed groups. In conclusion, dietary supplementation with bamboo shoot extract enhances hematological parameters, blood cell and nuclear morphology, and increases survival rates in Nile tilapia following infection.

RelB and C/EBPα critically regulate the development of Peyer's patch mononuclear phagocytes

To establish protection against harmful foreign antigens, the small intestine harbors guardian sites called Peyer's patches (PPs). PPs take up antigens through microfold (M) cells and transfer them to the sub-epithelial dome (SED), which contains a high density of mononuclear phagocytes (MPs), for T cell-priming. Accumulating evidence indicates that SED-MPs have unique functions other than T cell-priming to facilitate mucosal immune responses; however, the crucial factors regulating the functions of SED-MPs have not been determined. Here we performed transcriptome analysis, and identified the gene signatures of SED-MPs. Further data interpretation with transcription factor (TF) enrichment analysis estimated TFs responsible for the functions of SED-MPs. Among them, we found that RelB and C/EBPα were preferentially activated in SED-MPs. RelB-deficiency silenced the expression of IL-22BP and S100A4 by SED-MPs. On the other hand, C/EBPα-deficiency decreased the expression of lysozyme by SED-MPs, resulting the increased invasion of orally administered pathogenic bacteria into PPs and mesenteric lymph nodes. Our findings thus demonstrate that RelB and C/EBPα are essential to regulate the functions of SED-MPs.

Supplementation of recombinant human lysozyme into diets affects the growth performance, muscle quality, immunity and intestinal microbiota in large yellow croaker Larimichthyscrocea

The aim of the present study was to investigate the influence of supplementation of lysozyme (LZM) into diet on the growth performance, muscle quality, immunity, intestinal microbiota in large yellow croaker (Larimichthys crocea) with initial body weight of 194.5 ± 0.27 g. After a 70-day feeding trial, 6 experimental diets with LZM supplementation at 0 (LZM0), 10 (LZM10), 30 (LZM30), 50 (LZM50), 70 (LZM70) and 90 mg/kg (LZM90) were tested. Results showed that the fish in the LZM70 group exhibited the lowest feed conversion ratio and the highest weight gain (WG), along with the highest trypsin and Na+/K+ ATPase activities in intestine (P < 0.05). The LZM activity in serum and intestine was significantly reduced in all dietary LZM supplemented groups compared to the LZM0 group (P < 0.05). Compared with that in the LZM0 group, the gene expressions of claudin 11, bcl-2, nlrp 3, tnf α, il-10 and tgf β in intestine in the LZM90 group were significantly elevated, while bax and caspase3 were significantly downregulated (P < 0.05). Meanwhile, the group supplemented with 90 mg/kg of dietary LZM also increased muscle crude lipid content, springiness and drip loss, along with decreased crude protein content, shear force and hardness compared with other groups (P < 0.05). Furthermore, the results of intestinal microbiota showed that compared to those in the LZM0 group, relative abundances of Fusobacterium in the LZM30 and LZM90 groups were decreased, and the relative abundances of Achromobacter, Mycoplasma and Cetobacterium were increased. In conclusion, appropriate supplementation of LZM in diet promoted the growth performance, improved immunity, adjusted intestinal microbiota and muscle quality of large yellow croaker. Furthermore, the optimal level of dietary LZM supplementation for large yellow croaker was estimated to be 67.14 mg/kg based on the quadratic regression for WG.

Characterization and functional analysis of a novel goose-type lysozyme from teleost Sebastes schlegelii with implications for antibacterial defense and immune cell modulation

Lysozymes are crucial enzymes involved in the innate immune response against bacterial pathogens. In this study, we identified and characterized a goose-type lysozyme gene (SsLyG) from the black rockfish Sebastes schlegelii, an economically important aquaculture species. The deduced amino acid sequence of SsLyG contains 495 residues, which inculded a signal peptide, an immunoglobulin domain, and a goose egg-white lysozyme (GEWL) domain. Tissue expression analysis revealed the highest SsLyG levels in blood, and its transcription was significantly upregulated in the spleen and kidney upon bacterial and polyI:C challenges. Recombinant SsLyGE (rSsLyGE) exhibited lytic activity against Micrococcus lysodeikticus and concentration-dependent binding ability to Staphylococcus aureus and Micrococcus luteus. Furthermore, rSsLyGE promoted peripheral blood lymphocyte proliferation, enhanced macrophage respiratory burst activity, and increased reactive oxygen species production. RNA interference-mediated knockdown of SsLyG resulted in higher bacterial loads in the liver and spleen after Listonella anguillarum challenge, suggesting its role in early antibacterial defense. Collectively, these findings provide insights into the immune function of SsLyG and its potential application in developing antimicrobial strategies for aquaculture.

Roles of S100A1 and S100A10 from hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀) in immune response to Vibrio infection

The S100 proteins are highly conserved EF-hand calcium-binding proteins found only in vertebrates. In the current study, two S100 genes (S100A1 and S100A10) were successfully identified and characterized from hybrid grouper Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀. The deduced S100A10 protein contained two EF-hand domains, and S100A1 only possessed the N-terminal EF-hand. Phylogenetic analysis revealed that S100A1 and S100A10 from hybrid grouper were evolutionarily closely related to their counterparts in other selected vertebrates. Quantitative real-time PCR results revealed that the transcripts of S100A1 and S100A10 mRNA were ubiquitously distributed in all the examined tissues. After Vibrio alginolyticus infection, the expression of S100A1 and S100A10 in the spleen increased significantly. Moreover, overexpression of S100A1 and S100A10 could not only regulate the expression of interleukin 8 (IL-8), IL-10, and IL-16 in the head kidney, liver, and spleen, change the activities of acid phosphatase, catalase, lysozyme, and superoxide dismutase in serum, but also reduce the promoter activities of interferon 3 and nuclear factor kappa-B in vitro. Taken together, this study indicated that S100A1 and S100A10 participate in the immune response of hybrid grouper against bacterial infection.

Elucidation of the Binding Interaction between β-Sitosterol and Lysozyme using Molecular Docking, Molecular Dynamics and Surface Plasmon Resonance Analysis

In this study, the binding behavior of β-sitosterol with lysozyme (LZM) was elucidated by surface plasmon resonance (SPR), computational molecular docking and molecular dynamics simulation studies. Chicken egg white lysozyme (CEWLZM) served as a model protein. Tri-N-acetylchitotriose (NAG3) was used in the redocking experiments to generate precise binding location of the protein. β-sitosterol displayed a slightly better binding energy (-6.68±0.04 kcal/mol) compared to NAG3. Further molecular dynamics simulations and MMPBSA analysis revealed that residues Glu35, Gln57-Asn59, Trp62, Ile98, Ala107 and Trp108 contribute to the binding energy. Then, 2.5 mg/mL CEWLZM, 1X PBS buffer (pH 7.4) as running and coupling buffers, 30 μL/min as flow rate were applied for SPR analysis. Serial β-sitosterol injections (20-150 μM) were performed through SPR sensor surface. According to SPR binding study, KD value for β-sitosterol-CEWLZM binding interaction was calculated as 71.34±9.79 μM. The results could provide essential knowledge for nutrition, pharmaceutical science, and oral biology.

Phytogenic Feed Additives as a Sustainable Alternative to Antibiotics: Enhancing Growth and Disease Resistance in Nile Tilapia (Oreochromis niloticus)

Pathogens and challenging conditions in fish farming are common problems that cause mortality and reduce growth performance. Phytogenic feed additives can support the immunity of fish and thereby improve performance, production, and disease resistance. Two experiments with Nile Tilapia aimed to evaluate the effects of a matrix-encapsulated phytogenic additive (Digestarom® P.E.P. MGE) in different feed formulations, which vary in the marine meal inclusion level (5% and 12.8%), on growth performance and resistance against Streptococcus agalactiae. Fish were stocked in a recirculating aquaculture tank system per experiment and were fed with diets with or without the phytogenic supplementation for 8 weeks (six replicates per group). After an intraperitoneal injection with a sterilized saline solution and bath immersion with S. agalactiae (5 × 106 CFU/mL), mortality of the fish was recorded for 20 days. Independent of the diet formulation, the supplementation with the phytogenic feed additive significantly improved the fish production; feed conversion ratio; immune response (mainly lactic acid dehydrogenase, differential blood cell counts, and the lysozyme activity in blood); and fish survival after the S. agalactiae challenge. Thus, phytogenic feed additives are promising strategies to improve Nile tilapia production by enhancing fish growth performance, health, and protection against S. agalactiae infections.

The Unique Capability of Endolysin to Tackle Antibiotic Resistance: Cracking the Barrier

The lack of new antibacterial medicines and the rapid rise in bacterial resistance to antibiotics pose a major threat to individuals and healthcare systems. Despite the availability of various antibiotics, bacterial resistance has emerged for almost every antibiotic discovered to date. The increasing prevalence of multidrug-resistant bacterial strains has rendered some infections nearly untreatable, posing severe challenges to health care. Thus, the development of alternatives to conventional antibiotics is critical for the treatment of both humans and food-producing animals. Endolysins, which are peptidoglycan hydrolases encoded by bacteriophages, represent a promising new class of antimicrobials. Preliminary research suggests that endolysins are more effective against Gram-positive bacteria than Gram-negative bacteria when administered exogenously, although they can still damage the cell wall of Gram-negative bacteria. Numerous endolysins have a modular domain structure that divides their binding and catalytic activity into distinct subunits, which helps maximize their bioengineering and potential drug development. Endolysins and endolysin-derived antimicrobials offer several advantages as antibiotic substitutes. They have a unique mechanism of action and efficacy against bacterial persisters (without requiring an active host metabolism); subsequently, they target both Gram-positive and Gram-negative bacteria (including antibiotic-resistant strains), and mycobacteria. Furthermore, there has been limited evidence of endolysin being resistant. Because these enzymes target highly conserved links, resistance may develop more slowly compared to traditional antibiotics. This review provides an overview and insight of the potential applications of endolysins as novel antimicrobials.

Evaluation of longan (Dimocarpus longan) peel powder as fruit by-product additive in Nile tilapia (Oreochromis niloticus) feed: Effects on growth, immunity, and immune-antioxidant gene expressions

The study, herein, investigated the effects of the inclusion of longan peel (LP) powder in the diet of Nile Tilapia (Oreochromis niloticus), focusing on comparative evaluations of growth performance, immunity, and immune-antioxidant related gene expressions. For this purpose, a total of 300 healthy fish (average initial weight: 13.70 ± 0.06 g) were randomly distributed into five experimental treatment groups: 0 g kg-1 (LP0), 10 g kg-1 (LP10), 20 g kg-1 (LP20), 40 g kg-1 (LP40), and 80 g kg-1 (LP80), all in triplicate, for 60 days. The results indicated that dietary supplementation with LP exhibited a significant influence (P < 0.05) in weight gain (WG), specific growth rate (SGR) and provided a better feed conversion ratio (FCR) in contrast to the control group (0 g kg-1 LP). Moreover, skin mucus and serum immune parameters (lysozyme and peroxidase activity) were significantly higher (P < 0.05) in fish fed with different LP concentrations at both 4 and 8 weeks. Similarly, analysis of mRNA transcripts of immune (IL-1, IL-8, and LBP) and antioxidant (GSTa, GPX, and GSR) gene expressions showed a significant upregulation (P < 0.05) in LP-fed diet groups compared to the control group. Based on the polynomial regression analysis the inclusion of LP at 46-49 g kg-1 can be used effectively in Nile tilapia diets for improving the growth, immunity, and immune-antioxidant gene expressions. All in all, our results prove that LP is a very promising feed supplement for the Nile tilapia in the context of aquaculture.

Effects of Red Clover Isoflavones on Growth Performance, Immune Function, and Cecal Microflora of Mice

Isoflavone components extracted from red clover have anti-inflammatory, antioxidant and immune boosting effects. We hypothesize that red clover isoflavones (RCIs) achieve health-promoting effects via altering the gut microbiota. A total of 48 mice (20 ± 2 g) were randomly divided into a control group, low-dose group (0.05% RCIs in feed), middle-dose group (0.1% RCIs in feed), and high-dose group (0.2% RCIs in feed) with 12 mice per group. The feeding period was 20 d. The results showed that RCIs can increase the daily gain and decrease the ratio of feed to gain in mice. The organ indexes and blood biochemical indexes of the mice in each RCI group were in the normal range, indicating that RCIs do not damage liver or kidney function. RCI supplementation increased serum immunity and altered the microbial community structure in the cecum of the mice. RCIs can increase the diversity of beneficial bacteria such as Bacteroidaceae, Muribaculaceae, and Akkermansiaceae, and reduced the pathogenic Staphylococcaceae. Therefore, supplementing the diet with RCIs results in improved growth performance and notable alterations in the cecal microbiota in mice, and has potential applications as a feed additive to improve livestock production.

Multivalent chitobiose self-assembled glycostructures as ligands to lysozyme

Synthetic chitobiose-containing glycolipid (GL) and lipid (L) are prepared in order to secure self-assembled multivalent glycostructures, constituted with varying molar fractions of GL and L. The morphologies of glycostructures are uniform, as adjudged by dynamic light scattering (DLS) in solution and microscopies in the solid state. Presence of the ester linkage between the lipid and chitobiose moieties permit hydrolysis and disassembly of the self-assembled structures at acidic and alkaline pH. The avidity of chitobiose in the multivalent glycostructures to lysozyme follows the percentage of GL in the GL-L compositions in the order 50 % GL > 100 % GL-L > 10 % GL-L. The interaction with lysozyme occurs with fast association and slow dissociation kinetics, from which the equilibrium binding constant (Ka) is identified to be 2-4 orders of magnitude higher (Ka 105 to 107 M-1), as compared to monomeric chitobiose-lysozyme complexation in solution. When assessed for the antimicrobial lytic property of lysozyme, the multivalent chitobiose-lysozyme complex is found to delay the lytic property, when compared to the enzyme alone. The study establishes (i) the pH-sensitive multivalent chitobiose-containing glycostructures for high affinity binding to lysozyme; (ii) that the multivalent ligand presentation enables orders of magnitude higher equilibrium binding constants with enzyme lysozyme and (iii) that the lytic activity of the enzyme is delayed upon complexation with the multivalent glycostructures.

Postbiotics From Lactobacillus Johnsonii Activates Gut Innate Immunity to Mitigate Alcohol-Associated Liver Disease

Prolonged alcohol consumption disrupts the gut microbiota and the immune system, contributing to the pathogenesis of alcohol-associated liver disease (ALD). Probiotic-postbiotic intervention strategies can effectively relieve ALD by maintaining gut homeostasis. Herein, the efficacy of heat-killed Lactobacillus johnsonii (HKLJ) in mitigating alcoholic liver damage is demonstrated in mouse models of ALD. The gut-liver axis is identified as a pivotal pathway for the protective effects of L. johnsonii against ALD. Specifically, HKLJ is found to upregulate the expression of intestinal lysozymes, thereby enhancing the production of immunoregulatory substances from gut bacteria, which subsequently activated the Nucleotide-binding oligomerization domain 2 (NOD2)-interleukin (IL-23)-IL-22 innate immune axis. The elevated IL-22 upregulated the antimicrobial peptide synthesis to maintain intestinal homeostasis and moreover activated the Signal transducer and activator of Transcription3 (STAT3) pathway in the liver to facilitate the repair of hepatic injuries. The heat-killed L. johnsonii provoked immunity helps correct the gut microbiota dysbiosis, specifically by reversing the reduction of butyrate-producing bacteria (such as Faecalibaculum rodentium) and the expansion of opportunistic pathogens (such as Helicobacter sp. and Pichia kudriavzevii) induced by ethanol. The findings provide novel insights into the gut microbiota-liver axis that may be leveraged to enhance the treatment of ALD.

Mass spectrometry-based proteomic exploration of diverse murine macrophage cellular models

Immortalised cell lines that mimic their primary cell counterparts are fundamental to research, particularly when large cell numbers are required. Here, we report that immortalisation of bone marrow-derived macrophages (iBMDMs) using the J2 virus resulted in the loss of a protein of interest, MSR1, in WT cells by an unknown mechanism. This led us to perform an in-depth mass spectrometry-based proteomic characterisation of common murine macrophage cell lines (J774A.1, RAW264.7, and BMA3.1A7), in comparison with the iBMDMs, as well as primary BMDMs from both C57BL/6 and BALB/c mice. This analysis revealed striking differences in protein profiles associated with macrophage polarisation, phagocytosis, pathogen recognition, and interferon signalling. Among the cell lines, J774A.1 cells were the most similar to the gold standard primary BMDM model, whereas BMA3.1A7 cells were the least similar because of the reduction in abundance of several key proteins related closely to macrophage function. This comprehensive proteomic dataset offers valuable insights into the use and suitability of macrophage cell lines for cell signalling and inflammation research.

A modeling framework for detecting and leveraging node-level information in Bayesian network inference

Bayesian graphical models are powerful tools to infer complex relationships in high dimension, yet are often fraught with computational and statistical challenges. If exploited in a principled way, the increasing information collected alongside the data of primary interest constitutes an opportunity to mitigate these difficulties by guiding the detection of dependence structures. For instance, gene network inference may be informed by the use of publicly available summary statistics on the regulation of genes by genetic variants. Here we present a novel Gaussian graphical modeling framework to identify and leverage information on the centrality of nodes in conditional independence graphs. Specifically, we consider a fully joint hierarchical model to simultaneously infer (i) sparse precision matrices and (ii) the relevance of node-level information for uncovering the sought-after network structure. We encode such information as candidate auxiliary variables using a spike-and-slab submodel on the propensity of nodes to be hubs, which allows hypothesis-free selection and interpretation of a sparse subset of relevant variables. As efficient exploration of large posterior spaces is needed for real-world applications, we develop a variational expectation conditional maximization algorithm that scales inference to hundreds of samples, nodes and auxiliary variables. We illustrate and exploit the advantages of our approach in simulations and in a gene network study which identifies hub genes involved in biological pathways relevant to immune-mediated diseases.

Use of Transcriptomics to Identify Candidate Genes for Hematopoietic Differences Between Wujin and Duroc Pigs

Hematopoiesis is a complex physiological process that ensures renewal of blood cells to maintain normal blood circulation and immune function. Wujin pigs exhibit distinct characteristics such as tender meat, high fat storage, strong resistance to roughage, robust disease resistance, and oxidation resistance. Therefore, using Wujin pigs as models may offer valuable insights for hematopoietic-related studies. In this study, twelve healthy 35-day-old piglets, including six Wujin and six Duroc piglets of similar weight, were selected from each of the Wujin and Duroc pig groups and housed in single cages. After 30 days of feeding, blood and bone marrow samples were collected. Routine blood indices and hematopoietic-related serum biochemical indexes of Wujin and Duroc pigs were determined, and bone marrow gene expression levels were analyzed using transcriptomics. (1) Hemoglobin (Hb) and Mean Corpuscular Hemoglobin Concentration (MCHC) levels in Wujin pigs were significantly higher than in Duroc pigs (p < 0.05), and platelet counts and serum Hb levels in Wujin pigs were significantly lower than in Duroc pigs (p < 0.05). (2) A total of 312 significantly differentially expressed genes were identified between the pigs. Their functions were mainly related to blood systems, inflammation, and oxidation. Six differentially expressed genes may be related to hematopoietic function. (3) By combining the differential genes screened through sequencing with Weighted Gene Co-expression Network Analysis results, 16 hematopoietic function differential genes were obtained, mainly focusing on immunity, inflammation, and induction of apoptosis functions. Differences were present in the immune and inflammatory responses between Wujin pigs and Duroc pigs, suggesting that differences in hematopoietic function between the two breeds were related to antioxidant capacity and disease resistance.

Could tolerance to DNA be broken in the gut in systemic lupus erythematosus?

The bacteria in the human colon outnumber the total number of nucleated cells in the human body by approximately 10:1. The DNA that the bacteria contain is enriched around 20-fold in immune stimulatory CpG motifs compared to the DNA of host cells. In addition, this DNA can have alternative more immunogeneic DNA structures and it may be presented to the immune system alongside other proinflammatory bacterial innate ligands such as LPS. To ensure that this immunostimulatory combination is not pathogenic, the luminal boundary of host tissues in the human gastrointestinal tract is protected by cells secreting bactericides together with the secreted enzyme DNASE1L3 that can break down bacterial DNA. Cells with RNA encoding DNASE1L3 are particularly abundant in the gut-associated lymphoid tissue where bacteria are specifically sampled into the body, alongside B cells noted for their T independent function. Importantly, individuals with loss of function mutations in DNASE1L3 develop anti-DNA antibodies and lupus symptoms. In this review, we explore the possibility that a perfect storm might break tolerance to DNA: when bacterial DNA from microbiota that is not digested by DNASE1L3 directly encounters B cells that are not necessarily restricted by T cell dependence.

H2Se-evolving bio-heterojunctions promote cutaneous regeneration in infected wounds by inhibiting excessive cellular senescence

Pathogenic infection leads to excessive senescent cell accumulation and stagnation of wound healing. To address these issues, we devise and develop a hydrogen selenide (H2Se)-evolving bio-heterojunction (bio-HJ) composed of graphene oxide (GO) and FeSe2 to deracinate bacterial infection, suppress cellular senescence and remedy recalcitrant infected wounds. Excited by near-infrared (NIR) laser, the bio-HJ exerts desired photothermal and photodynamic effects, resulting in rapid disinfection. The crafted bio-HJ could also evolve gaseous H2Se to inhibit cellular senescence and dampen inflammation. Mechanism studies reveal the anti-senescence effects of H2Se-evolving bio-HJ are mediated by selenium pathway and glutathione peroxidase 1 (GPX1). More critically, in vivo experiments authenticate that the H2Se-evolving bio-HJ could inhibit cellular senescence and potentiate wound regeneration in rats. As envisioned, our work not only furnishes the novel gasotransmitter-delivering bio-HJ for chronic infected wounds, but also gets insight into the development of anti-senescence biomaterials.

Consortium of Lactobacillus crispatus 2029 and Ligilactobacillus salivarius 7247 Strains Shows In Vitro Bactericidal Effect on Campylobacter jejuni and, in Combination with Prebiotic, Protects Against Intestinal Barrier Dysfunction

Background/Objectives:Campylobacter jejuni (CJ) is the etiological agent of the world's most common intestinal infectious food-borne disease, ranging from mild symptoms to fatal outcomes. The development of innovative synbiotics that inhibit the adhesion and reproduction of multidrug-resistant (MDR) CJ in animals and humans, thereby preserving intestinal homeostasis, is relevant. We have created a synbiotic based on the consortium of Lactobacillus crispatus 2029 (LC2029), Ligilactobacillus salivarius 7247 (LS7247), and a mannan-rich prebiotic (Actigen®). The purpose of this work was to study the in vitro anti-adhesive and antagonistic activities of the created synbiotic against MDR CJ strains, along with its role in preventing intestinal barrier dysfunction, which disrupts intestinal homeostasis. Methods: A complex of microbiological, immunological, and molecular biological methods was used. The ability of the LC2029 and LS7247 consortium to promote intestinal homeostasis in vitro was assessed by the effectiveness of controlling CJ-induced TLR4 activation, secretion of pro-inflammatory cytokines, development of intestinal barrier dysfunction, and production of intestinal alkaline phosphatase (IAP). Results: All MDR CJ strains showed marked adhesion to human Caco-2, pig IPEC-J2, chicken CPCE, and bovine BPCE enterocytes. For the first time, we found that the prebiotic and cell-free culture supernatant (CFS) from the consortium of LC2029 and LS7247 strains exhibit an additive effect in inhibiting the adhesion of MDR strains of CJ to human and animal enterocytes. CFS from the LC2029 and LS7247 consortium increased the permeability of the outer and inner membranes of CJ cells, which led to extracellular leakage of ATP and provided access to the peptidoglycan of the pathogen for the peptidoglycan-degrading bacteriocins nisin and enterolysin A produced by LS7247. The LC2029 and LS7247 consortium showed a bactericidal effect on CJ strains. Co-cultivation of the consortium with CJ strains resulted in a decrease in the viability of the pathogen by 6 log. CFS from the LC2029 and LS7247 consortium prevented the growth of CJ-induced TLR4 mRNA expression in enterocytes. The LC2029 and LS7247 consortium inhibited a CJ-induced increase in IL-8 and TNF-α production in enterocytes, prevented CJ-induced intestinal barrier dysfunction, maintained the transepithelial electrical resistance of the enterocyte monolayers, and prevented an increase in intestinal paracellular permeability and zonulin secretion. CFS from the consortium stimulated IAP mRNA expression in enterocytes. The LC2029 and LS7247 consortium and the prebiotic Actigen represent a new synergistic synbiotic with anti-CJ properties that prevents intestinal barrier dysfunction and preserves intestinal homeostasis. Conclusions: These data highlight the potential of using a synergistic synbiotic as a preventive strategy for creating feed additives and functional nutrition products based on it to combat the prevalence of campylobacteriosis caused by MDR strains in animals and humans.

The role of the mucosal barrier system in maintaining gut symbiosis to prevent intestinal inflammation

In the intestinal tract, where numerous intestinal bacteria reside, intestinal epithelial cells produce and release various antimicrobial molecules that form a complex barrier on the mucosal surface. These barrier molecules can be classified into two groups based on their functions: those that exhibit bactericidal activity through chemical reactions, such as antimicrobial peptides, and those that physically hinder bacterial invasion, like mucins, which lack bactericidal properties. In the small intestine, where Paneth cells specialize in producing antimicrobial peptides, the chemical barrier molecules primarily inhibit bacterial growth. In contrast, in the large intestine, where Paneth cells are absent, allowing bacterial growth, the primary defense mechanism is the physical barrier, mainly composed of mucus, which controls bacterial movement and prevents their invasion of intestinal tissues. The expression of these barrier molecules is regulated by metabolites produced by bacteria in the intestinal lumen and cytokines produced by immune cells in the lamina propria. This regulation establishes a defense mechanism that adapts to changes in the intestinal environment, such as alterations in gut microbial composition and the presence of pathogenic bacterial infections. Consequently, when the integrity of the gut mucosal barrier is compromised, commensal bacteria and pathogenic microorganisms from outside the body can invade intestinal tissues, leading to conditions such as intestinal inflammation, as observed in cases of inflammatory bowel disease.

Bioactive components in the marsupial pouch and milk

Marsupials give birth to immunologically naïve young after a relatively short gestation period compared with eutherians. Consequently, the joey relies significantly on maternal protection, which is the focus of the present review. The milk and the pouch environment are essential contributors to maternal protection for the healthy development of joeys. In this review, we discuss bioactive components found in the marsupial pouch and milk that form cornerstones of maternal protection. These bioactive components include immune cells, immunoglobulins, the S100 family of calcium-binding proteins, lysozymes, whey proteins, antimicrobial peptides and other immune proteins. Furthermore, we investigated the possibility of the presence of plurifunctional components in milk and pouches that are potentially bioactive. These compounds include caseins, vitamins and minerals, oligosaccharides, lipids and microRNAs. Where applicable, this review addresses variability in bioactive components during different phases of lactation, designed to fulfil the immunological needs of the growing pouch young. Yet, there are numerous additional research opportunities to pursue, including uncovering novel bioactive components and investigating their modes of action, dynamics, stability and ability to penetrate the gut epithelium to facilitate systemic effects.

Cross-niche protection of kiwi plant against above-ground canker disease by beneficial rhizosphere Flavobacterium

Beneficial rhizosphere microorganisms are widely employed to shield crops from underground pathogen infections. In this study, we challenge this conventional idea by employing rhizosphere soil bacteria to safeguard kiwi plants against the above-ground canker, caused by Pseudomonas syringae pv. actinidiae (Psa). Microbiome comparisons were conducted in different resistant cultivars Actinidia chinensis var. deliciosa 'Hayward' and A. chinensis var. chinensis 'Hongyang'. Our findings reveal the most notable disparity in the rhizosphere soil microbiome, with the Flavobacterium significantly enriched in the rhizosphere soil of more resistant cultivar, 'Hayward'. We isolated Flavobacterium isolates and observed their efficacy in preventing Psa infection, which is further confirmed in field trial by using a representative strain Flavobacterium soyae F55. Furthermore, undescribed gene clusters responsible for antimicrobial metabolite biosynthesis were identified in F. soyae F55, and F. soyae F55 growth was evidently promoted by the root exudates of 'Hayward'. The results underscore the potential of beneficial rhizosphere soil bacteria in protection against above-ground disease.

The Equilibrium of Bacterial Microecosystem: Probiotics, Pathogenic Bacteria, and Natural Antimicrobial Substances in Semen

Semen is a complex fluid that contains spermatozoa and also functions as a dynamic bacterial microecosystem, comprising probiotics, pathogenic bacteria, and natural antimicrobial substances. Probiotic bacteria, such as Lactobacillus and Bifidobacterium, along with pathogenic bacteria like Pseudomonas aeruginosa and Escherichia coli, play significant roles in semen preservation and reproductive health. Studies have explored the impact of pathogenic bacteria on sperm quality, providing insights into the bacterial populations in mammalian semen and their influence on sperm function. These reviews highlight the delicate balance between beneficial and harmful bacteria, alongside the role of natural antimicrobial substances that help maintain this equilibrium. Moreover, we discuss the presence and roles of antimicrobial substances in semen, such as lysozyme, secretory leukocyte peptidase inhibitors, lactoferrin, and antimicrobial peptides, as well as emerging antibacterial substances like amyloid proteins. Understanding the interactions among probiotics, pathogens, and antimicrobial agents is crucial for elucidating semen preservation and fertility mechanisms. Additionally, the potential for adding probiotic bacteria with recombinant antibacterial properties presents a promising avenue for the development of new semen extenders. This review offers updated insights to understand the equilibrium of the bacterial microecosystem in semen and points toward innovative approaches for improving semen preservation.

Evolution of g-type lysozymes in metazoa: insights into immunity and digestive adaptations

Exploring the evolutionary dynamics of lysozymes is critical for advancing our knowledge of adaptations in immune and digestive systems. Here, we characterize the distribution of a unique class of lysozymes known as g-type, which hydrolyze key components of bacterial cell walls. Notably, ctenophores, and choanoflagellates (the sister group of Metazoa), lack g-type lysozymes. We reveal a mosaic distribution of these genes, particularly within lophotrochozoans/spiralians, suggesting the horizontal gene transfer events from predatory myxobacteria played a role in their acquisition, enabling specialized dietary and defensive adaptations. We further identify two major groups of g-type lysozymes based on their widespread distribution in gastropods. Despite their sequence diversity, these lysozymes maintain conserved structural integrity that is crucial for enzymatic activity, underscoring independent evolutionary pathways where g-type lysozymes have developed functionalities typically associated with different lysozyme types in other species. Specifically, using Aplysia californica as a reference species, we identified three distinct g-type lysozyme genes: two are expressed in organs linked to both feeding and defense, and the third exhibits broader distribution, likely associated with immune functions. These findings advance our understanding of the evolutionary dynamics shaping the recruitment and mosaic functional diversification of these enzymes across metazoans, offering new insights into ecological physiology and physiological evolution as emerging fields.

Postbiotic, anti-inflammatory, and immunomodulatory effects of aqueous microbial lysozyme in broiler chickens

Lysozymes, efficient alternative supplements to antibiotics, have several benefits in poultry production. In the present study, 120, one-day-old, Ross 308 broiler chickens of mixed sex, were allocated into 2 equal groups, lysozyme treated group (LTG) and lysozyme free group (LFG), to evaluate the efficacy of lysozyme (Lysonir®) usage via both drinking water (thrice) and spray (once). LTG had better (p = 0.042) FCR, and higher European production efficiency factor compared to LFG (p = 0.042). The intestinal integrity score of LTG was decreased (p = 0.242) compared to that of LFG; 0.2 vs. 0.7. Higher (p ≤ 0.001) intestinal Lactobacillus counts were detected in chickens of LTG. Decreased (p ≤ 0.001) IL-1β and CXCL8 values were reported in LTG. The cellular immune modulation showed higher (p ≤ 0.001) opsonic activity (MΦ and phagocytic index) in LTG vs. LFG at 25 and 35 days. Also, higher (p ≤ 0.001) local, IgA, and humoral, HI titers, for both Newcastle, and avian influenza H5 viruses were found in LTG compared to LFG. In conclusion, microbial lysozyme could improve feed efficiency, intestinal integrity, Lactobacillus counts, anti-inflammatory, and immune responses in broiler chickens.

Cell death induced by Lepeophtheirus salmonis labial gland protein 3 in salmonid fish leukocytes: A mechanism for disabling host immune responses

The salmon louse (Lepeophtheirus salmonis) is an ectoparasite feeding on mucus, skin, and blood of salmonids. On parasitised fish erosions and, at later lice stages, ulcerations appear at the louse feeding site. In susceptible species like Atlantic salmon (Salmo salar) with a limited rejection of lice, only a mild inflammatory response with minor influx of immune cells is seen at these lesions, as the salmon louse secrete proteins that can dampen immune responses. In a previous study, Lepeophtheirus salmonis labial gland protein 3 (LsLGP3) was suggested to dampen cellular responses, and the present study aimed at increasing our understanding of its mode of action. LsLGP3 was found to be secreted on to the host skin, and both in vivo and in vitro experiments were performed to elucidate its function. Histological analysis of the louse attachment site revealed an epidermal and dermal influx of mainly macrophages and granulocytes after 5 days post infestation. The immune cell influx was deeper in the dermis throughout the louse infestation, and LsLGP3 may be involved in dampening this response. Enriched populations of Atlantic salmon B-cells, T-cells, granulocytes, and monocytes were exposed to recombinant LsLGP3 (recLGP3) in vitro, resulting in a significant decrease in cell viability compared to non-exposed controls. An apoptotic cell morphology with "beads-on-a-string" like protrusions was seen in all leukocyte cell fractions after recLGP3 exposure, but not in erythrocytes or keratocytes. A decreased viability was also detected in pink salmon leucocytes, which was not in leucocytes from non-salmonid species. These functional insights suggest that LsLGP3 specifically induces apoptosis of salmonid leukocytes and is likely a key protein secreted by the lice that disables the Atlantic salmon ability to mount an adequate immune response towards the salmon louse. In vivo LsLGP3 knock down studies indicated that the effect is localised primarily at the lice feeding site, without affecting immune cells that are not situated adjacent to the lice-inflicted lesion. The findings from this study could significantly aid in the development of new immune based anti-salmon louse prophylactic measures and treatments.

When the Host Encounters the Cell Wall and Vice Versa

Peptidoglycan (PGN) and associated surface structures such as secondary polymers and capsules have a central role in the physiology of bacteria. The exoskeletal PGN heteropolymer is the major determinant of cell shape and allows bacteria to withstand cytoplasmic turgor pressure. Thus, its assembly, expansion, and remodeling during cell growth and division need to be highly regulated to avoid compromising cell survival. Similarly, regulation of the assembly impacts bacterial cell shape; distinct shapes enhance fitness in different ecological niches, such as the host. Because bacterial cell wall components, in particular PGN, are exposed to the environment and unique to bacteria, these have been coopted during evolution by eukaryotes to detect bacteria. Furthermore, the essential role of the cell wall in bacterial survival has made PGN an important signaling molecule in the dialog between host and microbes and a target of many host responses. Millions of years of coevolution have resulted in a pivotal role for PGN fragments in shaping host physiology and in establishing a long-lasting symbiosis between microbes and the host. Thus, perturbations of this dialog can lead to pathologies such as chronic inflammatory diseases. Similarly, pathogens have devised sophisticated strategies to manipulate the system to enhance their survival and growth.

Hyaluronic acid/chitin thermosensitive hydrogel loaded with TGF-β1 promotes meniscus repair in rabbit meniscus full-thickness tear model

Repair of the damaged meniscus is a scientific challenge owing to the poor self-healing potential of the white area of the meniscus. Tissue engineering provides a new method for the repair of meniscus injuries. In this study, we explored the superiority of 2% hyaluronic acid chitin hydrogel in temperature sensitivity, in vitro degradation, biocompatibility, cell adhesion, and other biological characteristics, and investigated the advantages of hyaluronic acid (HA) and Transforming Growth Factor β1 (TGF-β1) in promoting cell proliferation and a matrix formation phenotype. The hydrogel loaded with HA and TGF-β1 promoted cell proliferation. The HA + TGF-β1 mixed group showed the highest glycosaminoglycan (GAG) content and promoted cell migration. Hydroxypropyl chitin (HPCH), HA, and TGF-β1 were combined to form a composite hydrogel with a concentration of 2% after physical cross-linking, and this was injected into a rabbit model of a meniscus full-thickness tear. After 12 weeks of implantation, the TGF-β1 + HA/HPCH composite hydrogel was significantly better than HPCH, HA/HPCH, TGF-β1 + HPCH, and the control group in promoting meniscus repair. In addition, the new meniscus tissue of the TGF-β1 + HA/HPCH composite hydrogel had a tissue structure and biochemical content similar to that of the normal meniscus tissue.

Pangolin scales as adaptations for innate immunity against pathogens

BACKGROUND

Pangolins are the only mammals that have overlapping scales covering most of their bodies, and they play a crucial role in the ecosystem, biological research, and human health and disease. Previous studies indicated pangolin scale might provide an important mechanical defense to themselves. The origin and exact functions of this unique trait remain a mystery. Using a multi-omics analysis approach, we report a novel functional explanation for how mammalian scales can provide host-pathogen defense.

RESULTS

Our data suggest that pangolin scales have a sophisticated structure that could potentially trap pathogens. We identified numerous proteins and metabolites exhibiting antimicrobial activity, which could suggest a role for scales in pathogen defense. Notably, we found evidence suggesting the presence of exosomes derived from diverse cellular origins, including mesenchymal stem cells, immune cells, and keratinocytes. This observation suggests a complex interplay where various cell types may contribute to the release of exosomes and antimicrobial compounds at the interface between scales and viable tissue. These findings indicate that pangolin scales may serve as a multifaceted defense system, potentially contributing to innate immunity. Comparisons with human nail and hair revealed pangolin-specific proteins that were enriched in functions relating to sensing, immune responses, neutrophil degranulation, and stress responses. We demonstrated the antimicrobial activity of key pangolin scale components on pathogenic bacteria by antimicrobial assays.

CONCLUSIONS

This study identifies a potential role of pangolin scales and implicates scales, as possible determinants of pathogen defense due to their structure and contents. We indicate for the first time the presence of exosomes in pangolin scales and propose the new functions of scales and their mechanisms. This new mechanism could have implications for multiple fields, including providing interesting new research directions and important insights that can be useful for synthesizing and implementing new biomimetic antimicrobial approaches.