Immune Defense System Research Articles

3D imaging of the synovium defines an immune defense system at the blood-joint barrier.

3D imaging of the synovium defines an immune defense system at the blood-joint barrier.

Pathobiont and symbiont contribute to microbiota homeostasis through Malpighian tubules-gut countercurrent flow in Bactrocera dorsalis.

Host-gut microbiota interactions are more complex than good or bad. Both gut symbiotic bacteria and pathobionts can provide essential functions to their host in one scenario and yet be detrimental to host health in another. So, these gut-dwelling bacteria must be tightly controlled to avoid harmful effects on the host. However, how pathobionts and other symbiotic bacteria coordinate to establish a host immune defense system remains unclear. Here, using a Tephritidae fruit fly Bactrocera dorsalis, we report that both pathobionts and other gut symbiotic bacteria release tyramine, which is recognized by the host insects. These tyramines induce the formation of insect-conserved Malpighian tubules-gut countercurrent flow upon bacterial infection, which requires tyramine receptors and aquaporins. At the same time, pathobionts but not gut symbiotic bacteria induce the generation of reactive oxygen species, which are preserved by the countercurrent flow, promoting bacteria elimination through increasing gut peristalsis. More importantly, our results show that the Malpighian tubules-gut countercurrent flow maintains proper microbiota composition. Our work suggests a model where pathobiont-induced reactive oxygen species are preserved by Malpighian tubules-gut countercurrent flow involving both pathobionts and symbiotic bacteria. Furthermore, our work provides a Malpighian tubules-gut interaction that ensures efficient maintenance of the gut microbiota.

Mechanism and nanotechnological-based therapeutics for tolerance and resistance of bacterial biofilms.

Bacterial biofilms are one of the most relevant drivers of chronic and recurrent infections and a significant healthcare problem. Biofilms were formed by cross-linking of hydrophobic extracellular polymeric substances (EPS), such as proteins, polysaccharides, and eDNA, which were synthesized by bacteria themselves after adhesion and colonization on biological surfaces. They had the characteristics of dense structure and low drug permeability, leading to tolerance and resistance of biofilms to antibiotics and to host responses. Within a biofilm, microbial cells show increased tolerance to both immune system defense mechanisms and antimicrobials than the same cells in the planktonic state. It is one of the key reasons for the failure of traditional clinical drug to treat infectious diseases. Currently, no drugs are available to attack bacterial biofilms in the clinical setting. The development of novel preventive and therapeutic strategies is urgently needed to allow an effective management of biofilm-associated infections. Based on the properties of nanomaterials and biocompatibility, nanotechnology had the advantages of specific targeting, intelligent delivery and low toxicity, which could realize efficient intervention and precise treatment of biofilm-associated infections. In this paper, the mechanisms of bacterial biofilm resistance to antibiotics and host response tolerance were elaborated. Meanwhile, This paper highlighted multiple strategies of biofilms eradication based on nanotechnology. Nanotechnology can interfere with biofilm formation by destroying mature biofilm, modulating biofilm heterogeneity, inhibiting bacterial metabolism, playing antimicrobial properties, activating immunity and enhancing biofilm penetration, which is an important new anti-biofilm preparation. In addition, we presented the key challenges still faced by nanotechnology in combating bacterial biofilm infections. Utilization of nanotechnology safely and effectively should be further strengthened to confirm the safety aspects of their clinical application.

MDA5 Is a Major Determinant of Developing Symptoms in Critically Ill COVID-19 Patients.

Apart from the skin and mucosal immune barrier, the first line of defense of the human immune system includes MDA5 (ifih1 gene) which acts as a cellular sensor protein for certain viruses including SARS-CoV-2. Upon binding with viral RNA, MDA5 activates cell-intrinsic innate immunity, humoral responses, and MAVS (mitochondrial antiviral signaling). MAVS signaling induces type I and III interferon (IFN) expressions that further induce ISGs (interferon stimulatory genes) expressions to initiate human cell-mediated immune responses and attenuate viral replication. SARS-CoV-2 counteracts by producing NSP1, NSP2, NSP3, NSP5, NSP7, NSP12, ORF3A, ORF9, N, and M protein and directs anti-MDA5 antibody production presumably to antagonize IFN signaling. Furthermore, COVID-19 resembles several diseases that carry anti-MDA5 antibodies and the current COVID-19 vaccines induced anti-MDA5 phenotypes in healthy individuals. GWAS (genome-wide association studies) identified several polymorphisms (SNPs) in the ifih1-ifn pathway genes including rs1990760 in ifih1 that are strongly associated with COVID-19, and the associated risk allele is correlated with reduced IFN production. The genetic association of SNPs in ifih1 and ifih1-ifn pathway genes reinforces the molecular findings of the critical roles of MDA5 in sensing SARS-CoV-2 and subsequently the IFN responses to inhibit viral replication and host immune evasion. Thus, MDA5 or its pathway genes could be targeted for therapeutic development of COVID-19.

Immunostimulation Signaling via Toll-like Receptor 2 Activation: A Molecular Mechanism of Lactococcus lactis OTG1204 In Vitro and In Vivo.

The immune system's defense against pathogens involves innate and adaptive responses, crucial in maintaining overall health. Immunosuppressed states render individuals more susceptible to potential diseases, indicating the need for effective strategies to bolster immune functions. Although the immunostimulatory effects of various probiotics have been studied, the specific effects and molecular mechanisms of Lactococcus lactis OTG1204 (OTG1204) remain unknown. In this study, the aim was to investigate the molecular mechanisms of OTG1204 in RAW 264.7 macrophages, the key effector cells of the innate immune system involved in host defense and inflammatory responses. Additionally, in this study, the effects of OTG1204 on cyclophosphamide (CTX)-induced immunosuppression states were investigated, thereby demonstrating its potential as an immune stimulant. To assess the macrophage activation ability and underlying mechanisms of OTG1204, RAW 264.7 cells were utilized with transfection, enzyme-linked immunosorbent assay, and quantitative real-time PCR analyses. Furthermore, to evaluate the immunostimulatory effects under immunosuppressed conditions, CTX-induced immunosuppression mice model was employed, and analyses were performed using hematoxylin and eosin staining, flow cytometry, and microbiota examination. OTG1204 activated RAW 264.7 macrophages, leading to increased production of nitric oxide, prostaglandin E2, and cytokines. This immune activation was mediated through the upregulation of toll-like receptor 2, which subsequently activated the nuclear factor-κB (NF-kB) and mitogen-activated protein kinase (MAPK)/activator protein 1 (AP-1) pathways, thereby stimulating the immune response. In CTX-treated mice, OTG1204 recovered body weight, spleen, and mesenteric lymph node indices, and natural killer cell activity. It re-established populations of innate and adaptive immune cells and activated T cells to secrete cytokines. We also examined the gut barrier integrity and microbiota composition to assess OTG1204's impact on intestinal health, as these factors play a significant role in immune enhancement. OTG1204 enhanced gut barrier integrity by upregulating mucin 2 and tight junction proteins and modulated the gut microbiota by restoring the Firmicutes/Bacteroidetes balance and reducing the abundance of Actinobacteria and Tenericutes. These results suggest that OTG1204 may serve as an effective probiotic for immune enhancement and gut health management by targeting the NF-κB and MAPK/AP-1 pathways, with minimal side effects.

Ganoderma lucidum triterpenoids investigating their role in medicinal applications and genomic protection.

Ganoderma lucidum (GL) is a white rot fungus widely used for its pharmacological properties and health benefits. GL consists of several biological components, including polysaccharides, sterols, and triterpenoids. Triterpenoids are often found in GL in the form of lanostane-type triterpenoids with quadrilateral carbon structures. The study revealed that triterpenoids have diverse biological properties and can be categorized based on their functional groups. Triterpenoids derived from GL have shown potential medicinal applications. They can disrupt the cell cycle by inhibiting β-catenin or protein kinase C activity, leading to anti-cancer, anti-inflammatory, and anti-diabetic effects. They can also reduce the production of inflammatory cytokines, thus mitigating inflammation. Additionally, triterpenoids have been found to enhance the immune system's defenses against various health conditions. They possess antioxidant, antiparasitic, anti-hyperlipidemic, and antimicrobial activities, making them suitable for pharmaceutical applications. Furthermore, triterpenoids are believed to afford radioprotection to DNA, protecting it from radiation damage. This review focuses on the types of triterpenoids isolated from GL, their synthesis pathways, and their chemical structures. Additionally, it highlights the pharmacological characteristics of triterpenoids derived from GL, emphasizing their significant role in various therapeutic applications and health benefits for both humans and animals.

Topological rearrangements activate the HerA-DUF anti-phage defense system.

Leveraging the rich structural information provided by AlphaFold, we used integrated experimental approaches to characterize the HerA-DUF4297 (DUF) anti-phage defense system, in which DUF is of unknown function. To infer the function of DUF, we performed structure-guided genomic analysis and found that DUF homologs are universally present in bacterial immune defense systems. One notable homolog of DUF is Cap4, a universal effector with nuclease activity in CBASS, the most prevalent anti-phage system in bacteria. To test the inferred nuclease function of DUF, we performed biochemical experiments and discovered that the DUF only exhibits activity against DNA substrates when it is bound by HerA. To understand how HerA activates DUF, we determined the structures of DUF and the HerA-DUF complex. DUF forms large oligomeric assemblies with or without HerA, suggesting that oligomerization per se is not sufficient for DUF activation. Instead, DUF activation requires dramatic topological rearrangements that propagate from HerA to the entire HerA-DUF complex, leading to reorganization of DUF for effective DNA cleavage. We further validated these structural insights by structure- guided mutagenesis. Together, these findings reveal dramatic topological rearrangements throughout the HerA-DUF complex, challenge the long-standing dogma that protein oligomerization alone activates immune signaling, and may inform the activation mechanism of CBASS.

Antimicrobial Effect of Zinc Oxide Nanoparticle Coating on Titanium 6 Aluminum 4 Vanadium (Ti-6Al-4V)-Fixed Orthodontic Retainer Substrate

Abstract Objectives Due to its excellent biocompatibility, superior mechanical qualities, and exceptional corrosion resistance, titanium 6 aluminum 4 vanadium (Ti-6Al-4V) alloy is frequently used for medical and orthodontic purposes as a fixed retainer after active orthodontic treatment. Titanium lacks the antibacterial characteristics and is bioinert, this may influence the usage of such materials in the field of biomedical applications. Bacterial adhesion to the orthodontic retainer surface is a common first step in infection; this is followed by bacterial colonization ending with the formation of a biofilm. Once biofilm forms, it is highly resistant to medicines and the host immune system's defense mechanism, making it difficult to remove the biofilm from orthodontic retainer. This study aimed to test the antimicrobial effect of a zinc oxide (ZnO) nanoparticle coating on Ti-6Al-4V orthodontic retainers. Materials and Methods ZnO nanoparticles, with a particle size of 10 to 30 nm, were used to coat the alloy using the electrophoretic deposition method. Various parameters and surface characterization tests were employed to obtain an optimized sample. This sample was subjected to the microbial adherence optical density test to examine the adherence of Streptococcus mutans, Lactobacillus acidophilus bacteria, and Candida albicans. Results The optimized sample had a 5-mg/L ZnO concentration, applied voltage of 50 V, and a 1-cm distance between electrodes. The ZnO coating significantly reduced microbial adherence compared to uncoated samples, effectively inhibiting bacterial development. Conclusion Electrophoretic deposition is an efficient and cost-effective technique for coating orthodontic titanium retainer substrates. Coating Ti-6Al-4V with ZnO nanoparticles increased the antimicrobial effectiveness of the material and as the concentration of the nanoparticles rises, the antimicrobial effect increases too.

LncRNA NRIR serves as a biomarker for systemic lupus erythematosus and participates in the disease progression.

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder characterized by a malfunction of the body's immune defense system. The objective of the present investigation was to examine the expression and diagnostic significance of NRIR in SLE and to prove whether it is involved in the progression of SLE. The study involved 110 participants, including 55 healthy individuals and 55 SLE patients. The expression levels of NRIR, miR-31-5p, and ICAM-1 were measured using qRT-PCR. The ROC curve was performed to assess the diagnostic significance of NRIR in SLE patients. Pearson correlation analysis was utilized to explore the relationship between NRIR and other indicators. Cytokines including IL-4, IL-6, and IL-21, along with IgG levels, were assessed using ELISA. The interaction between NRIR and miR-31-5p was validated using a dual-luciferase reporter assay. Upregulated expression of NRIR was observed in individuals with SLE, serving a diagnostic function for SLE. Additionally, abnormal expression of NRIR impacted the viability of CD4+ T cells within SLE patients. NRIR could negatively modulate the expression of miR-31-5p. LncRNA NRIR may be a potential biomarker for SLE and is likely involved in the progression of SLE.

Comparative Assessment of Water Models in Protein-Glycan Interaction: Insights from Alchemical Free Energy Calculations and Molecular Dynamics Simulations.

Accurate computational simulations of protein-glycan dynamics are crucial for a comprehensive understanding of critical biological mechanisms, including host-pathogen interactions, immune system defenses, and intercellular communication. The accuracy of these simulations, including molecular dynamics (MD) simulation and alchemical free energy calculations, critically relies on the appropriate parameters, including the water model, because of the extensive hydrogen bonding with glycan hydroxyl groups. However, a systematic evaluation of water models' accuracy in simulating protein-glycan interaction at the molecular level is still lacking. In this study, we used full atomistic MD simulations and alchemical absolute binding free energy (ABFE) calculations to investigate the performance of five distinct water models in six protein-glycan complex systems. We evaluated water models' impact on structural dynamics and binding affinity through over 5.8 μs of simulation time per system. Our results reveal that most protein-glycan complexes are stable in the overall structural dynamics regardless of the water model used, while some show obvious fluctuations with specific water models. More importantly, we discover that the stability of the binding motif's conformation is dependent on the water model chosen when its residues form weak hydrogen bonds with the glycan. The water model also influences the conformational stability of the glycan in its bound state according to density functional theory (DFT) calculations. Using alchemical ABFE calculations, we find that the OPC water model exhibits exceptional consistency with experimental binding affinity data, whereas commonly used models such as TIP3P are less accurate. The findings demonstrate how different water models affect protein-glycan interactions and the accuracy of binding affinity calculations, which is crucial in developing therapeutic strategies targeting these interactions.

Genomic Insights into Disease Resistance in Sunflower (Helianthus annuus): Identifying Key Regions and Candidate Genes for Verticillium dahliae Resistance.

Sunflower (Helianthus annuus) is a globally significant field crop, and disease resistance is crucial for ensuring yield stability and crop quality. Verticillium dahliae is a notorious soilborne pathogen that causes Verticillium Wilt (VW) and threatens sunflower production worldwide. In this study, we conducted a comprehensive assessment of sunflower resistance to V. dahliae across 231 sunflower cultivar lines, from the Sunflower Association Mapping (SAM) population. We employed EMMAX and ridge regression best linear unbiased prediction (rrBLUP) and identified 148 quantitative trait loci (QTLs) and 23 putative genes associated with V. dahliae resistance, including receptor like kinases, cell wall modification, transcriptional regulation, plant stress signalling and defense regulation genes. Our enrichment and quantitative real-time PCR validation results highlight the importance of membrane vesicle trafficking in the sunflower immune system for efficient signaling and defense upon activation by V. dahliae. This study also reveals the polygenic architecture of V. dahliae resistance in sunflowers and provides insights for breeding sunflower cultivars resistant to VW. This research contributes to ongoing efforts to enhance crop resilience and reduce yield losses due to VW, ultimately benefiting sunflower growers and the agricultural sector.

Yak DEFB123 alleviates lung injury caused by Klebsiella pneumoniae through MAPKs signaling pathway

Beta-defensins, such as β-defensin 123 (DEFB123), are vital components of the immune system's defense against infections due to their strong antimicrobial properties and capacity for modulating the body's immunological responses. In this study, we successfully cloned and analyzed the yak DEFB123 gene sequence. Subsequently, we obtained recombinant protein DEFB123 (rDEFB123) through prokaryotic expression. Our results demonstrate that rDEFB123 effectively inhibits the growth of Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. Furthermore, rDEFB123 enhances the phagocytic activity of macrophages by regulating specific factors. In a mouse model infected with Klebsiella pneumoniae, the administration of rDEFB123 showed significantly lower levels of serum ALT and AST compared to the control group. Moreover, IFN-γ and IgG were significantly increased in the rDEFB123-treated groups, indicating an enhanced immune response. In the MAPKs signaling pathway of the infected mouse lungs, the expressions of JNK, TRAF2, TRAF6, MIF, and IL-1β genes were downregulated in the rDEFB123-treated groups. Moreover, the levels of p-JNK protein were significantly decreased in these groups as well. Klebsiella pneumoniae caused systemic infection with organ damage in mice. However, the administration of rDEFB123 suppressed the expressions of inflammatory factors, thereby mitigating organ injury and regulating the activity of apoptosis-related factors to enhance immunity. These findings provide valuable theoretical data for future exploration of the functionality and potential applications of DEFB123 in yak.

Nanomaterials in Immunology: Bridging Innovative Approaches in Immune Modulation, Diagnostics, and Therapy.

The intersection of immunology and nanotechnology has provided significant advancements in biomedical research and clinical applications over the years. Immunology aims to understand the immune system's defense mechanisms against pathogens. Nanotechnology has demonstrated its potential to manipulate immune responses, as nanomaterials' properties can be modified for the desired application. Research has shown that nanomaterials can be applied in diagnostics, therapy, and vaccine development. In diagnostics, nanomaterials can be used for biosensor development, accurately detecting biomarkers even at very low concentrations. Therapeutically, nanomaterials can act as efficient carriers for delivering drugs, antigens, or genetic material directly to targeted cells or tissues. This targeted delivery improves therapeutic efficacy and reduces the adverse effects on healthy cells and tissues. In vaccine development, nanoparticles can improve vaccine durability and extend immune responses by effectively delivering adjuvants and antigens to immune cells. Despite these advancements, challenges regarding the safety, biocompatibility, and scalability of nanomaterials for clinical applications are still present. This review will cover the fundamental interactions between nanomaterials and the immune system, their potential applications in immunology, and their safety and biocompatibility concerns.

Transcriptome Profiling of Gene Expression in Atlantic Salmon (Salmo salar) at Early Stage of Development.

For Atlantic salmon development, the most critical phase is the early development stage from egg to fry through alevin. However, the studies investigating the early development of Atlantic salmon based on RNA-seq are scarce and focus only on one stage of development. Therefore, using the RNA-seq technology, the assessment of different gene expressions of various early development stages (egg, alevin, and fry) was performed on a global scale. Over 22GB of clean data was generated from 9 libraries with three replicates for each stage with over 90% mapping efficiency. A total of 5534 genes were differentially expressed, among which 19, 606, and 826 genes were specifically expressed in each stage, respectively. The transcriptome analysis showed that the number of differentially expressed genes (DEGs) increased as the Atlantic salmon progressed in development from egg to fry stage. In addition, gene ontology enrichment demonstrated that egg and alevin stages are characterized by upregulation of genes involved in spinal cord development, neuron projection morphogenesis, axonogenesis, and cytoplasmic translation. At the fry stage, upregulated genes were enriched in the muscle development process (muscle cell development, striated muscle cell differentiation, and muscle tissue development), immune system (defense response and canonical NF-kappaB signal transduction), as well as epidermis development. These results suggest that the early development of Atlantic salmon is characterized by a dynamic shift in gene expression and DEGs between different stages, which provided a solid foundation for the investigation of Atlantic salmon development.

Nutritional Aspects for Modulation of Poultry Immune Stimulation

The immune system's defense mechanism has been affected by the management and nutrition conditions in poultry production. In biological aspects, Bursa Fabricius and Thymus are primary lymphoid organs that defend the body against diseases. The spleen, cecal tonsils, immunoglobulins, and various forms of mucosal immunity, BALT (bronchus-associated lymphoid tissue), MALT (mucosa-associated lymphoid tissue), CALT (conjunctiva-associated lymphoid tissue), and GALT (gut-associated lymphoid tissue), are also vital to their overall health. The management program (environmental conditions, heating, lighting practices) and nutritional supplementation (feed ingredients, composition, and feed additives) significantly affect birds' immunity and performance. Dietary supplementation enhances immune system activation by improving the lymphoid tissues and beneficial immune modulators and responses. During the past fifteen years, alternative feed additives (amino acids, minerals, vitamins, probiotics, prebiotics) have impacted animal production performance and immunity. Besides, feed additives, such as probiotics, prebiotics, vitamins, minerals, and organic acids, are essential for sustaining hormonal, physiological, and immunological processes. These additives, probiotics, vitamins (A, C, D, E), mineral (selenium) supplementations, and organic acids boost the immune system's activity against microbial pathogens and physiological stress mechanisms. At the last point, this paper aims to review the current improvement in the relationship between nutrition and immunity in poultry.

Effects of physical inactivity behavior during COVID-19 pandemic on physical fitness, body composition, inflammatory cytokine, and immunocytes in older adults: A retrospective and prospective study

The prolonged period of COVID-19 has ingrained physical inactivity as a habit, leading to a reluctance to move. This has resulted in a decline in physical fitness and the loss of a healthy body composition. While this trend is particularly noticeable among the older adults, its impact on the immune cell defense system, which is crucial for minimizing viral infections, remains unclear. This study aimed to investigate the physical fitness, body composition, cytokines and immunocytes of older adults who engaged in physical activity (PA) before the COVID-19 pandemic but had to stop it due to the lockdown. A total of 172 older adults aged 61 to 85 years participated in this study: 90 in non-PA group (NPAG, 34 men and 56 women), and 82 in PA group (PAG, 29 men and 53 women). Physical inactivity was 45.13 ± 5.67 weeks in the NPAG and 1.70 ± 0.43 weeks in the PAG. Although there was no significant difference in calorie intake, PA volume showed a significant decrease in NPGA (P < 0.001). VO₂max, strength, and sit-ups decreased in NPAG, whereas they maintained or increased in PAG (Ps < 0.001). NPAG experienced an increase in fat mass (∼33.0 %), along with a decrease in muscle mass (∼10.4 %), but PAG showed slight increases (∼1.1 % vs. ∼1.5 %, Ps < 0.001). Interleukin-6 (∼38.9 %), tumor necrosis factor-α (∼38.3 %), and C-reactive protein (∼33.6 %) increased, whereas immunocytes decreased in NPAG (Ps < 0.001). In contrast, those in PAG showed the opposite phenomenon. This study indicates that even during the COVID-19 situation, maintaining active PA in the older adults helps retain beneficial physical fitness and body composition, reduces inflammatory factors, and contributes to preserving or enhancing the function of immunocytes.

Whole-genome DNA methylation profiling revealed epigenetic regulation of NF-κB signaling pathway involved in response to Vibrio alginolyticus infection in the Pacific oyster, Crassostrea gigas

DNA methylation, an essential epigenetic alteration, is tightly linked to a variety of biological processes, such as immune response. To identify the epigenetic regulatory mechanism in Pacific oyster (Crassostrea gigas), whole-genome bisulfite sequencing (WGBS) was conducted on C. gigas at 0 h, 6 h, and 48 h after infection with Vibrio alginolyticus. At 6 h and 48 h, a total of 11,502 and 14,196 differentially methylated regions (DMRs) were identified (p<0.05, FDR<0.001) compared to 0 h, respectively. Gene ontology (GO) analysis showed that differentially methylated genes (DMGs) were significantly enriched in various biological pathways including immunity, cytoskeleton, epigenetic modification, and metabolic processes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that transcription machinery (ko03021) is one of the most important pathways. Integrated transcriptome and methylome analyses allowed the identification of 167 and 379 DMG-related DEGs at 6 h and 48 h, respectively. These genes were significantly enriched in immune-related pathways, including nuclear factor kappa B (NF-κB) signaling pathway (ko04064) and tumor necrosis factor (TNF) signaling pathway (ko04668). Interestingly, it's observed that the NF-κB pathway could be activated jointly by TNF Receptor Associated Factor 2 (TRAF2) and Baculoviral IAP Repeat Containing 3 (BIRC3, the homolog of human BIRC2) which were regulated by DNA methylation in response to the challenge posed by V. alginolyticus infection. Through this study, we provided insightful information about the epigenetic regulation of immunity-related genes in the C. gigas, which will be valuable for the understanding of the innate immune system modulation and defense mechanism against bacterial infection in invertebrates.

A sandwich FRET biosensor for lysozyme detection based on peptide-functionalized gold nanoparticles and FAM-labeled aptamer

Lysozyme (LYZ) plays a crucial role in the body's immune defense system. Monitoring LYZ levels can provide valuable insights into the diagnosis and severity assessment of various diseases. Traditionally, antibody-based sandwich assays are employed for LYZ detection, but they are often time-consuming and operationally complicated. In this research, a novel sandwich FRET biosensor was developed, which enables rapid detection of LYZ based on peptide-functionalized gold nanoparticles (pAuNPs) and FAM-labeled aptamer (Apt-FAM). Initially, a mixture of Apt-FAM and pAuNPs resulted in partial quenching of the Apt-FAM fluorescence emission through an inner filter effect (IFE), with negligible energy transfer because of the electrostatic repulsion between the negatively charged pAuNPs and Apt-FAM. The introduction of LYZ into the mixture drove the specific binding of Apt-FAM and pAuNPs to LYZ, facilitating the formation of a pAuNPs-LYZ-aptamer sandwich structure. The formation of this complex drew the pAuNPs and Apt-FAM into close enough proximity to enable FRET to occur, which in turn effectively quenched the fluorescence emission of FAM. The decrease in FAM fluorescence intensity was correlated with the increasing concentration of LYZ. Thus, a sandwich FRET biosensor was successfully developed for LYZ detection with a linear detection range of 0–1.75 μM and a detection limit of 85 nM. Additionally, the biosensor allowed visual detection of LYZ in a 96-well microplate, with a rapid response time of just 15 s. This study introduces a innovative sandwich FRET biosensor that combines aptamer and peptide recognition elements, offering a fast and antibody-free method for protein detection.

Rational design of PspAlgL to improve its thermostability and anti-biofilm activity against Pseudomonas aeruginosa

Pseudomonas aeruginosa biofilm enhances tolerance to antimicrobials and immune system defenses. Alginate is an important component of biofilm and a virulence factor of P. aeruginosa. The degradation of alginate by alginate lyases has come to serve as an adjunctive therapeutic strategy against P. aeruginosa biofilm, but poor stability of the enzyme limited this application. Thus, PspAlgL, an alginate lyase, can degrade acetylated alginate but has poor thermostability. The 3D structure of PspAlgL was predicted, and the thermostability of PspAlgL was rationally designed by GRAPE strategy, resulting in two variants with better stability. These variants, PspAlgLS270F/E311P and PspAlgLG291S/E311P, effectively degraded the alginate in biofilm. In addition, compared with PspAlgL, these variants were more efficient in inhibiting biofilm formation and degrading the established biofilm of P. aeruginosa PAO1, and they were also able to destroy the biofilm attached to catheters and to increase the sensitivity of P. aeruginosa to the antibiotic amikacin. This study provides one potential anti-biofilm agent for P. aeruginosa infection.

Simultaneous Discovery–Invention in Corporate R&amp;D: Lessons from the CRISPR Case

AbstractSome companies invest in fundamental research, but many struggle when developing novel in‐house scientific knowledge and integrating it into their new inventions. While the literature advocates revised approaches to better understand this phenomenon, we investigate the processes that lead to Simultaneous Discovery–Invention (SDI). By adopting an abductive process, we propose a model that highlights the mechanisms of SDI. Notably, we reveal that teams must preserve independence in creative exploration during scientific knowledge creation and invention generation while maintaining intensive original knowledge exchange among them. We also demonstrate that anomaly detection and peer validation mechanisms are mandatory for SDI. We evaluate our model with a case study in the food industry: the discovery that CRISPR–Cas9 is an adaptative defense immune system of bacteria and the associated innovations in this industry. Finally, we discuss the insights provided by our model and the implications of our case study.