Effect of mouthwash containing poly l-Lysine and glycerol monolaurate on oral Helicobacter pylori relating to biofilm eradication, anti-adhesion, and pro-inflammatory cytokine suppression.

Background/purpose: Helicobacter pylori has been found to be related to periodontitis, and the oral cavity has been considered a reservoir for H. pylori gastritis infection. Thus, this study evaluated the effect of mouthwash containing poly l-Lysine and glycerol monolaurate on inhibiting H. pylori growth, biofilm formation, cell cytotoxicity, adhesion ability, cagA mRNA expression, and pro-inflammatory cytokines stimulated by H. pylori. Materials and methods: Nineteen H. pylori strains were isolated from the oral cavity. The effectiveness of mouthwash containing poly l-Lysine and glycerol monolaurate was examined for its ability to inhibit H. pylori growth and biofilm formation and was tested for cell viability in oral epithelial cells (H357), gastric adenocarcinoma cells (AGS), and periodontal ligament cells (PDL). Additionally, the mouthwash was tested for reducing cagA mRNA expression, adhesion ability to H357 and AGS cells, and pro-inflammatory cytokines stimulated with H. pylori in AGS and PDL cells. Results: The mouthwash containing poly l-Lysine and glycerol monolaurate could eradicate the biofilm by 14.9-19.9% after incubation at 5 min, and cell viability revealed 77.2, 79.8, and 100.0% for AGS, H357, and PDL cells, respectively. Moreover, the mouthwash containing poly l-Lysine and glycerol monolaurate could down-regulate cagA mRNA expression, reduce adhesion of H. pylori by approximately 9.5-47.8% for H357 cells and 24.5-62.9% for AGS cells, and decrease pro-inflammatory cytokines, especially interleukin-8, stimulated with H. pylori. Conclusion: Mouthwash containing poly l-Lysine and glycerol monolaurate could inhibit H. pylori growth and reduce their virulence expression. The mouthwash also revealed low cytotoxicity to oral and gastric cells.

Bacillaceae serine proteases and Streptomyces epsilon-poly-L-lysine synergistically inactivate Caliciviridae by inhibiting RNA genome release.

Human norovirus (HuNoV) is an enteric infectious pathogen belonging to the Caliciviridae family that causes occasional epidemics. Circulating alcohol-tolerant viral particles that are readily transmitted via food-borne routes significantly contribute to the global burden of HuNoV-induced gastroenteritis. Moreover, contact with enzymes secreted by other microorganisms in the environment can impact the infectivity of viruses. Hence, understanding the circulation dynamics of Caliciviridae is critical to mitigating epidemics. Accordingly, in this study, we screened whether environmentally abundant secretase components, particularly proteases, affect Caliciviridae infectivity. Results showed that combining Bacillaceae serine proteases with epsilon-poly-L-lysine (EPL) produced by Streptomyces-a natural antimicrobial-elicited anti-Caliciviridae properties, including against the epidemic HuNoV GII.4_Sydney_2012 strain. In vitro and in vivo biochemical and virological analyses revealed that EPL has two unique synergistic viral inactivation functions. First, it maintains an optimal pH to promote viral surface conformational changes to the protease-sensitive structure. Subsequently, it inhibits viral RNA genome release via partial protease digestion at the P2 and S domains in the VP1 capsid. This study provides new insights regarding the high-dimensional environmental interactions between bacteria and Caliciviridae, while promoting the development of protease-based anti-viral disinfectants.

Whole-cell biocatalysis for ε-poly-l-lysine production by a food-grade recombinant Bacillus subtilis.

ε-Poly-l-lysine (ε-PL), a natural food preservative with various advantages, is primarily produced by Streptomyces. It has attracted considerable attentions for the outstanding antibacterial activity, safety, heat stability, water solubility and other remarkable properties. In this study, a food-grade recombinant Bacillus subtilis was constructed for the biocatalysis of ε-PL. Firstly, the d-alanine racemase gene (alrA) was deleted from the genome of Bacillus subtilis 168 to construct an auxotrophic B. subtilis 168 (alrA-). Based on the shuttle plasmid pMA5, a food-grade plasmid pMA5a was constructed by replacing the genes of kanamycin resistance (Kanr) and ampicillin resistance (Ampr) with alrA and the gene encoding α-peptide of ß-galactosidase (lacZα), respectively. Subsequently, codon-optimized ε-PL synthase gene (pls) and P-pls were ligated into pMA5a and transformed in E. coli DH5α and expressed in B. subtilis 168 (alrA-). Finally, the whole-cell biocatalysis conditions for ε-PL production by B. subtilis 168 (alrA-)/pMA5a-pls were optimized, and the optimal conditions were 30°C, pH 4, l-lysine concentration of 0.6 g/L, bacterial concentration of 15 % (w/v) and a catalytic time of 7 h. The ε-PL production reached a maximum of 0.33 ± 0.03 g/L. The product was verified to be ε-PL by HPLC and tricine-SDS-PAGE. The information obtained in this study shows critical reference for the food-grade heterologous expression of ε-PL.

Cellular and Molecular Insights into the Divergence of Neural Stem Cells on Matrigel and Poly-l-lysine Interfaces.

Poly-l-lysine (PLL) and Matrigel, both classical coating materials for culture substrates in neural stem cell (NSC) research, present distinct interfaces whose effect on NSC behavior at cellular and molecular levels remains ambiguous. Our investigation reveals intriguing disparities: although both PLL and Matrigel interfaces are hydrophilic and feature amine functional groups, Matrigel stands out with lower stiffness and higher roughness. Based on this diversity, Matrigel surpasses PLL, driving NSC adhesion, migration, and proliferation. Intriguingly, PLL promotes NSC differentiation into astrocytes, whereas Matrigel favors neural differentiation and the physiological maturation of neurons. At the molecular level, Matrigel showcases a wider upregulation of genes linked to NSC behavior. Specifically, it enhances ECM-receptor interaction, activates the YAP transcription factor, and heightens glycerophospholipid metabolism, steering NSC proliferation and neural differentiation. Conversely, PLL upregulates genes associated with glial cell differentiation and amino acid metabolism and elevates various amino acid levels, potentially linked to its support for astrocyte differentiation. These distinct transcriptional and metabolic activities jointly shape the divergent NSC behavior on these substrates. This study significantly advances our understanding of substrate regulation on NSC behavior, offering novel insights into optimizing and targeting the application of these surface coating materials in NSC research.

ε-Poly-l-lysine: A Naturally Occurring Biodegradable Polypeptide for Selective Detection of 5-Nitroimidazole Antibiotics in Animal Products and Living Cells via Fluorescence.

The 5-nitroimidazole (5-NI) class of antibiotics, such as metronidazole, ornidazole, secnidazole, and tinidazole, are widely used to prevent bacterial infection in humans and livestock industries. However, their overuse contaminates the farmed animal products and water bodies. Hence, a selective, sensitive, and cost-effective method to detect 5-NI antibiotics is the need of the hour. Herein, we report a rapid, inexpensive, and efficient sensing system to detect 5-NI drugs using an as-prepared solution of ε-poly-l-lysine (ε-PL), a naturally occurring and biodegradable homopolypeptide that has an intrinsic fluorescence via clustering-triggered emission. The low nanomolar detection limit (3.25-3.97 nM) for the aforementioned representative 5-NI drugs highlights the sensitivity of the system, outperforming most of the reported sensors alike. The resulting fluorescence quenching was found to be static in nature. Importantly, excellent recovery (100.26-104.41%) was obtained for all real samples and animal products tested. Visual detection was demonstrated by using paper strips and silica gel for practical applications. Furthermore, ε-PL could detect 5-NI antibiotics in living 3T3-L1 mouse fibroblast cells via cellular imaging. Taken together, the present work demonstrates the detection of 5-NI antibiotics using a biocompatible natural polypeptide, ε-PL, and represents a simple and inexpensive analytical tool for practical application.

Attapulgite-enhanced ε-poly-l-lysine for heightened antibacterial efficiency against Pseudomonas syringae pv. Tomato.

ε-Poly-l-lysine (ε-PL) is an effective antimicrobial peptide for controlling fungal plant diseases, exhibiting significant antifungal activity and safety. Despite its known efficacy, the potential of ε-PL in combating plant bacterial diseases remains underexplored. This study evaluated the effectiveness of ε-PL and its nanomaterial derivative in managing tomato bacterial spot disease caused by Pseudomonas syringae pv. tomato. Results indicated that ε-PL substantially inhibited the growth of Pseudomonas syringae pv. tomato. Additionally, when ε-PL was loaded onto attapulgite (encoded as ATT@PL), its antibacterial effect was significantly enhanced. Notably, the antibacterial efficiency of ATT@PL containing 18.80 µg/mL ε-PL was even close to that of 100 µg/mL pure ε-PL. Further molecular study results showed that, ATT@PL stimulated the antioxidant system and the salicylic acid signaling pathway in tomatoes, bolstering the plants disease resistance. Importantly, the nanocomposite demonstrated no negative effects on both seed germination and plant growth, indicating its safety and aligning with sustainable agricultural practices. This study not only confirmed the effectiveness of ε-PL in controlling tomato bacterial spot disease, but also introduced an innovative high antibacterial efficiency ε-PL composite with good bio-safety. This strategy we believe can also be used in improving other bio-pesticides, and has high applicability in agriculture practice.

A 3D-printable gelatin/alginate/ε-poly-l-lysine hydrogel scaffold to enable porcine muscle stem cells expansion and differentiation for cultured meat development.

The mass proliferation of seed cells and imitation of meat structures remain challenging for cell-cultured meat production. With excellent biocompatibility, high water content and porosity, hydrogels are frequently-studied materials for anchorage-dependent cell scaffolds in biotechnology applications. Herein, a scaffold based on gelatin/alginate/ε-Poly-l-lysine (GAL) hydrogel is developed for skeletal muscle cells, which has a great prospect in cell-cultured meat production. In this work, the hydrogel GAL-4:1, composed of gelatin (5 %, w/v), alginate (5 %, w/v) and ε-Poly-l-lysine (molar ratio vs. alginate: 4:1) is selected as cell scaffold based on Young's modulus of 11.29 ± 1.94 kPa, satisfactory shear-thinning property and suitable porous organized structure. The commercially available C2C12 mouse skeletal myoblasts and porcine muscle stem cells (PMuSCs), are cultured in the 3D-printed scaffold. The cells show strong ability of attachment, proliferation and differentiation after induction, showing high biocompatibility. Furthermore, the cellular bioprinting is performed with GAL-4:1 hydrogel and freshly extracted PMuSCs. The extracted PMuSCs exhibit high viability and display early myogenesis (desmin) on the 3D scaffold, suggesting the great potential of GAL hydrogel as 3D cellular constructs scaffolds. Overall, we develop a novel GAL hydrogel as a 3D-printed bioactive platform for cultured meat research.

Transcriptional Analysis Revealing the Improvement of ε-Poly-L-lysine Production from Intracellular ROS Elevation after Botrytis cinerea Induction.

Gray mold, caused by Botrytis cinerea, poses significant threats to various crops, while it can be remarkably inhibited by ε-poly-L-lysine (ε-PL). A previous study found that B. cinerea extracts could stimulate the ε-PL biosynthesis of Streptomyces albulus, while it is unclear whether the impact of the B. cinerea signal on ε-PL biosynthesis is direct or indirect. This study evaluated the role of elevated reactive oxygen species (ROS) in efficient ε-PL biosynthesis after B. cinerea induction, and its underlying mechanism was disclosed with a transcriptome analysis. The microbial call from B. cinerea could arouse ROS elevation in cells, which fall in a proper level that positively influenced the ε-PL biosynthesis. A systematic transcriptional analysis revealed that this proper dose of intracellular ROS could induce a global transcriptional promotion on key pathways in ε-PL biosynthesis, including the embden-meyerhof-parnas pathway, the pentose phosphate pathway, the tricarboxylic acid cycle, the diaminopimelic acid pathway, ε-PL accumulation, cell respiration, and energy synthesis, in which sigma factor HrdD and the transcriptional regulators of TcrA, TetR, FurA, and MerR might be involved. In addition, the intracellular ROS elevation also resulted in a global modification of secondary metabolite biosynthesis, highlighting the secondary signaling role of intracellular ROS in ε-PL production. This work disclosed the transcriptional mechanism of efficient ε-PL production that resulted from an intracellular ROS elevation after B. cinerea elicitors' induction, which was of great significance in industrial ε-PL production as well as the biocontrol of gray mold disease.

Polycations as Aptamer-Binding Modulators for Sensitive Fluorescence Anisotropy Assay of Aflatoxin B1.

Fluorescence induced by the excitation of a fluorophore with plane-polarized light has a different polarization depending on the size of the fluorophore-containing reagent and the rate of its rotation. Based on this effect, many analytical systems have been implemented in which an analyte contained in a sample and labeled with a fluorophore (usually fluorescein) competes to bind to antibodies. Replacing antibodies in such assays with aptamers, low-cost and stable oligonucleotide receptors, is complicated because binding a fluorophore to them causes a less significant change in the polarization of emissions. This work proposes and characterizes the compounds of the reaction medium that improve analyte binding and reduce the mobility of the aptamer-fluorophore complex, providing a higher analytical signal and a lower detection limit. This study was conducted on aflatoxin B1 (AFB1), a ubiquitous toxicant contaminating foods of plant origins. Eight aptamers specific to AFB1 with the same binding site and different regions stabilizing their structures were compared for affinity, based on which the aptamer with 38 nucleotides in length was selected. The polymers that interact reversibly with oligonucleotides, such as poly-L-lysine and polyethylene glycol, were tested. It was found that they provide the desired reduction in the depolarization of emitted light as well as high concentrations of magnesium cations. In the selected optimal medium, AFB1 detection reached a limit of 1 ng/mL, which was 12 times lower than in the tris buffer commonly used for anti-AFB1 aptamers. The assay time was 30 min. This method is suitable for controlling almond samples according to the maximum permissible levels of their contamination by AFB1. The proposed approach could be applied to improve other aptamer-based analytical systems.

Branched poly-l-lysine for cartilage penetrating carriers.

Joint diseases, such as osteoarthritis, often require delivery of drugs to chondrocytes residing within the cartilage. However, intra-articular delivery of drugs to cartilage remains a challenge due to their rapid clearance within the joint. This problem is further exacerbated by the dense and negatively charged cartilage extracellular matrix (ECM). Cationic nanocarriers that form reversible electrostatic interactions with the anionic ECM can be an effective approach to overcome the electrostatic barrier presented by cartilage tissue. For an effective therapeutic outcome, the nanocarriers need to penetrate, accumulate, and be retained within the cartilage tissue. Nanocarriers that adhere quickly to cartilage tissue after intra-articular administration, transport through cartilage, and remain within its full thickness are crucial to the therapeutic outcome. To this end, we used ring-opening polymerization to synthesize branched poly(l-lysine) (BPL) cationic nanocarriers with varying numbers of poly(lysine) branches, surface charge, and functional groups, while maintaining similar hydrodynamic diameters. Our results show that the multivalent BPL molecules, including those that are highly branched (i.e., generation two), can readily adhere and transport through the full thickness of cartilage, healthy and degenerated, with prolonged intra-cartilage retention. Intra-articular injection of the BPL molecules in mouse knee joint explants and rat knee joints showed their localization and retention. In summary, this study describes an approach to design nanocarriers with varying charge and abundant functional groups while maintaining similar hydrodynamic diameters to aid the delivery of macromolecules to negatively charged tissues.

Effect of Chitosan and Hyperbranched Poly-L-Lysine Treatment on Quality of Cucumber (Cucumis sativus L.) during Storage.

To enhance the storage time of cucumbers, this research investigated the impact of chitosan (CS) and hyperbranched poly-L-lysine (HBPL) on the quality and nutritional attributes of cucumbers when stored at a temperature of 25 °C. The results demonstrated that sensory evaluation scores for cucumbers treated with a CS-HBPL combination were significantly higher than the control (CK), CS, and HBPL groups. On the 18th day of storage, cucumbers in the CK group exhibited significant decay and softening; however, there was a decrease in hardness observed in the CS-HBPL group and no decay or noticeable sour taste was detected. Furthermore, compared to the CK group, treatment with CS-HBPL effectively delayed cucumber decay and weight loss rate while significantly inhibiting decreases in cucumber hardness and growth of surface microorganisms. Additionally, it substantially reduced losses of soluble protein content as well as vitamin C (Vc), reducing sugars, and total phenolic compounds within cucumbers, which were 4.7 mg/g, 4.7 mg/g, 0.94 mg/g, and 0.52 mg/kg, respectively. Moreover, compared to the CK group, combined treatment with CS-HBPL significantly inhibited malondialdehyde (MDA) accumulation and reducing relative electrolyte permeability within cucumbers, which were 1.45 µmol·g-1FW and 29.82%. Furthermore, it notably enhanced activities of superoxide dismutase (SOD) and catalase (CAT), while exerting a significant inhibitory effect on polyphenol oxidase (PPO). In summary, the combined CS-HBPL treatment successfully prolonged cucumber shelf life at room temperature, enabling new possibilities for extending cucumber shelf life.

Unveiling novel anti-viral mechanisms of ε-poly-l-lysine on tobacco mosaic virus-infected Nicotiana tabacum through microRNA and transcriptome sequencing.

MicroRNAs (miRNAs) play important roles in plant defense against various pathogens. ε-poly-l-lysine (ε-PL), a natural anti-microbial peptide produced by microorganisms, effectively suppresses tobacco mosaic virus (TMV) infection. To investigate the anti-viral mechanism of ε-PL, the expression profiles of miRNAs in TMV-infected Nicotiana tabacum after ε-PL treatment were analyzed. The results showed that the expression levels of 328 miRNAs were significantly altered by ε-PL. Degradome sequencing was used to identify their target genes. Integrative analysis of miRNAs target genes and gene-enriched GO/KEGG pathways indicated that ε-PL regulates the expression of miRNAs involved in critical pathways of plant hormone signal transduction, host defense response, and plant pathogen interaction. Subsequently, virus induced gene silencing combined with the short tandem targets mimic technology was used to analyze the function of these miRNAs and their target genes. The results indicated that silencing miR319 and miR164 reduced TMV accumulation in N. benthamiana, indicating the essential roles of these miRNAs and their target genes during ε-PL-mediated anti-viral responses. Collectively, this study reveals that microbial source metabolites can inhibit plant viruses by regulating crucial host miRNAs and further elucidate anti-viral mechanisms of ε-PL.

Epsilon-poly-l-lysine microneedle patch loaded with amorphous doxycycline nanoparticles for synergistic treatment of skin infection.

The development of antibiotic-loaded microneedles has been hindered for years by limited excipient options, restricted drug-loading space, poor microneedle formability, and short-term drug retention. Therefore, this study proposes a dissolving microneedle fabricated from the host-defense peptide ε-poly-l-lysine (EPL) as an antibacterial adjuvant system for delivering antibiotics. EPL serves not only as a major matrix material for the microneedle tips, but also as a broad-spectrum antibacterial agent that facilitates the intracellular accumulation of the antibiotic doxycycline (DOX) by increasing bacterial cell membrane permeability. Furthermore, the formation of physically crosslinked networks of EPL affords microneedle tips with improved formability, good mechanical properties, and amorphous nanoparticles (approximately 7.2 nm) of encapsulated DOX. As a result, a high total loading content of both antimicrobials up to 2319.1 µg/patch is achieved for efficient transdermal drug delivery. In a Pseudomonas aeruginosa-induced deep cutaneous infection model, the EPL microneedles demonstrates potent and long-term effects by synergistically enhancing antibiotic activities and prolonging drug retention in infected lesions, resulting in remarkable therapeutic efficacy with 99.91 % (3.04 log) reduction in skin bacterial burden after a single administration. Overall, our study highlights the distinct advantages of EPL microneedles and their potential in clinical antibacterial practice when loaded with amorphous DOX nanoparticles.

Graphene oxide/ε-poly-L-lysine self-assembled functionalized coatings improve the biocompatibility and antibacterial properties of titanium implants.

The construction of an antibacterial biological coating on titanium surface plays an important role in the long-term stability of oral implant restoration. Graphene oxide (GO) has been widely studied because of its excellent antibacterial properties and osteogenic activity. However, striking a balance between its biological toxicity and antibacterial properties remains a significant challenge with GO. ε-poly-L-lysine (PLL) has broad-spectrum antibacterial activity and ultra-high safety performance. Using Layer-by-layer self-assembly technology (LBL), different layers of PLL/GO coatings and GO self-assembly coatings were assembled on the surface of titanium sheet. The materials were characterized using scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle test. The antibacterial properties of Porphyromonas gingivalis (P.g.) were analyzed through SEM, coated plate experiment, and inhibition zone experiment. CCK-8 was used to determine the cytotoxicity of the material to MC3T3 cells, and zebrafish larvae and embryos were used to determine the developmental toxicity and inflammatory effects of the material. The results show that the combined assembly of 20 layers of GO and PLL exhibits good antibacterial properties and no biological toxicity, suggesting a potential application for a titanium-based implant modification scheme.

Surface Modification of Zn-Cu Alloy with Heparin Nanoparticles for Urinary Implant Applications.

In this work, an investigation on the Zn-Cu alloy coated with heparin was conducted in order to explore the potentiality of its application as a feasible alternative for biodegradable implants, with the specific goal of addressing the issue of encrustation in the urinary system. The stability of the nanoparticles were characterized by dynamic light scattering. Typical surface characterization such as X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy were used to demonstrate a successful immobilization of the NPs. The in vitro corrosion behavior was studied by potentiodynamic polarization and immersion tests in artificial urine (AU) at 37 °C. The 8 weeks in vivo degradation, encrustation resistance, hemocompatibility, and histocompatibility were investigated by means of implantation into the bladders of rats. Both in vitro and in vivo degradation tests exhibited a higher degradation rate for Zn-Cu and NPs groups when compared to pure Zn. Histological evaluations and hemocompatibility revealed that there was no tissue damage or pathological alterations caused by the degradation process. Furthermore, antiencrustation performance and urinalysis results confirmed that the modified alloy demonstrated significant encrustation inhibitory properties and bactericidal activity compared to the pure Zn control. Our findings highlight the potential of this modified alloy as an antiencrustation biodegradable ureteral stent.

Multi-step strategies for synergistic treatment of urinary tract infections based on D-xylose-decorated antimicrobial peptide carbon dots.

Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC), often reoccur due to the formation of intracellular bacterial colonies (IBCs) and antibiotic resistance. Given the significance of YadC for UPEC infection in our previous study, we developed D-xylose-decorated ɛ-poly-L-lysine (εPL)-based carbon dots (D-xyl@εPLCDs) that can be traced, and employed multi-step approaches to elucidate the functional roles of D-xyl@εPLCDs in UPEC infection. Compared to undecorated particles, D-xyl@εPLCDs demonstrate YadC-dependent bacterial targeting and exhibit enhanced bactericidal activities both intracellularly and extracellularly. Moreover, pre-treatment of D-xyl@εPLCDs before infection blocked the subsequent adhesion and invasion of UPEC to bladder epithelial cells 5637. Increase of ROS production and innate immune responses were observed in bladder epithelial cells 5637 treated with D-xyl@εPLCDs. In addition, treatment of D-xyl@εPLCDs post-infection facilitated clearance of UPEC in the bladders of the UTI mouse model, and reduced ultimate number of neutrophils, macrophages and inflammatory responses raised by invaded bacteria. Collectively, we presented a comprehensive evaluating system to show that D-xyl@εPLCDs exhibits superior bactericidal effects against UPEC, making them a promising candidate for drug development in clinical UTI therapeutics.

Co-delivery of siAEG-1 and doxorubicin to treat osteosarcoma via nanomicelles for azide-alkyne "click" conjugation of poly(l-lysine) dendrons onto Zein.

Astrocyte elevated gene-1 (AEG-1) oncogene is a notorious and evolving target in a variety of human malignancies including osteosarcoma. The RNA interference (RNAi) has been clinically proven to effectively knock down specific genes. To successfully implement RNAi in vivo, protective vectors are required not only to protect unstable siRNAs from degradation, but also to deliver siRNAs to target cells with controlled release. Here, we synthesized a Zein-poly(l-lysine) dendrons non-viral modular system that enables efficient siRNA-targeted AEG-1 gene silencing in osteosarcoma and encapsulation of antitumor drugs for controlled release. The rational design of the ZDP integrates the non-ionic and low immunogenicity of Zein and the positive charge of the poly(l-lysine) dendrons (DPLL) to encapsulate siRNA and doxorubicin (DOX) payloads via electrostatic complexes and achieve pH-controlled release in a lysosomal acidic microenvironment. Nanocomplexes-directed delivery greatly improves siRNA stability, uptake, and AEG-1 sequence-specific knockdown in 143B cells, with transfection efficiencies comparable to those of commercial lipofectamine but with lower cytotoxicity. This AEG-1-focused RNAi therapy supplemented with chemotherapy inhibited, and was effective in inhibiting the growth in of osteosarcoma xenografts mouse models. The combination therapy is an alternative or combinatorial strategy that can produce durable inhibitory responses in osteosarcoma patients.

Epsilon-poly-l-lysine alleviates brown blotch disease of postharvest Agaricus bisporus mushrooms by directly inhibiting Pseudomonas tolaasii and inducing mushroom disease resistance.

The natural antimicrobial peptide, epsilon-poly-l-lysine (ε-PL), is widely acknowledged as a food preservative. However, its potential in managing bacterial brown blotch disease in postharvest edible mushrooms and the associated mechanism remain unexplored. In this study, concentrations of ε-PL ≥ 150 mg L-1 demonstrated significant inhibition effects, restraining over 80% of growth and killed over 99% of Pseudomonas tolaasii (P. tolaasii). This inhibition effect occurred in a concentration-dependent manner. The in vivo findings revealed that treatment with 150 mg L-1 ε-PL effectively inhibited P. tolaasii-caused brown blotch disease in Agaricus bisporus (A. bisporus) mushrooms. Plausible mechanisms underlying ε-PL's action against P. tolaasii in A. bisporus involve: (i) damaging the cell morphology and membrane integrity, and increasing uptake of propidium iodide and leakage of cellular components of P. tolaasii; (ii) interaction with intracellular proteins and DNA of P. tolaasii; (iii) inhibition of P. tolaasii-induced activation of polyphenol oxidase, elevation of antioxidative enzyme activities, stimulation of phenylpropanoid biosynthetic enzyme activities and metabolite production, and augmentation of pathogenesis-related protein contents in A. bisporus mushrooms. These findings suggest promising prospects for the application of ε-PL in controlling bacterial brown blotch disease in A. bisporus.

Investigating the Respiratory and Energy Metabolism Mechanisms behind ε-Poly-L-lysine Chitosan Coating's Improved Preservation Effectiveness on Tremella fuciformis.

Freshly harvested Tremella fuciformis contains high water content with an unprotected outer surface and exhibits high respiration rates, which renders it prone to moisture and nutrient loss, leading to decay during storage. Our research utilized ε-poly-L-lysine (ε-PL) and chitosan as a composite coating preservative on fresh T. fuciformis. The findings revealed that the ε-PL + chitosan composite coating preservative effectively delayed the development of diseases and reduced weight loss during storage compared to the control group. Furthermore, this treatment significantly decreased the respiration rate of T. fuciformis and the activity of respiratory metabolism-related enzymes, such as alternative oxidase (AOX), cytochrome c oxidase (CCO), succinic dehydrogenase (SDH), 6-phosphogluconate dehydrogenase, and glucose-6-phosphate dehydrogenase (6-PGDH and G-6-PDH). Additionally, the composite coating preservative also delayed the depletion of ATP and ADP and maintained higher levels of the energy charge while preserving low levels of AMP. It also sustained heightened activities of Mg2+-ATPase, Ca2+-ATPase, and H+-ATPase enzymes. These results demonstrate that utilizing the ε-PL + chitosan composite coating preservative can serve as a sufficiently safe and efficient method for prolonging the shelf life of post-harvest fresh T. fuciformis.

Activity of Epsilon-poly-L-lysine against Multidrug-Resistant Pseudomonas aeruginosa and Klebsiella pneumoniae Isolates of Urinary Tract Infections.

Pseudomonas aeruginosa and Klebsiella pneumoniae are notorious for their resistance to antibiotics and propensity for biofilm formation, posing significant threats to human health. Epsilon-poly-L-lysine (ε-PL) emerges as a naturally occurring antimicrobial poly(amino acid), which positions it as a prospective agent for addressing challenges linked to multidrug resistance. ε-PL symbolizes a promising avenue in the pursuit of efficacious therapeutic strategies and warrants earnest consideration within the realm of clinical treatment. Thus, our objective was to determine the antibiotic susceptibility profiles of 38 selected P. aeruginosa and ESBL-producing K. pneumoniae clinical isolates and determine the ability of ε-PL to inhibit biofilm formation. After PCR analysis, detection of genes related to ß-lactamases was observed among the selected isolates of P. aeruginosa [blaSPM (35.7%), blaKPC (35.7%), blaSHV (14.3%), blaCTX-M (14.3%), blaOXA (14.3%), blaTEM (7.1%), blaPER (7.1%), blaVIM (7.1%), and blaVIM-2 (7.1%)] and K. pneumoniae [blaCTX-M (91.7%), blaTEM (83.3%), blaKPC (16.7%), blaNDM (12.5%), and blaOXA (4.2%)]. The results of testing the activity of ε-PL against the clinical isolates showed relatively high minimum inhibitory concentrations (MICs) for the P. aeruginosa (range: 8-64 µg/mL) and K. pneumoniae isolates (range: 16-32 µg/mL). These results suggest the need for prior optimization of ε-PL concerning its viability as an alternative to antibiotics for treating infections caused by P. aeruginosa and K. pneumoniae of clinical origin. It is noteworthy that, in the context of a low antibiotic discovery rate, ε-PL could play a significant role in this quest, considering its low toxicity and the unlikely development of resistance. Upon exposure to ε-PL, P. aeruginosa and K. pneumoniae isolates exhibited a reduction in biofilm production, with ε-PL concentration showing an inverse relationship, particularly in isolates initially characterized as strong or moderate producers, indicating its potential as a natural antimicrobial agent with further research needed to elucidate optimal concentrations and application methods across different bacterial species. Further research is needed to optimize its use and explore its potential in various applications.