Advances in material design and applications are highly dependent on the development of particle surface engineering strategies. However, few universal methods can functionalize particles of ...different compositions, sizes, shapes, and structures. The amyloid‐like lysozyme assembly‐mediated surface functionalization of inorganic, polymeric or metal micro/nanoparticles in a unique amyloid‐like phase‐transition buffer containing lysozyme are described. The rapid formation of a robust nanoscale phase‐transitioned lysozyme (PTL) coating on the particle surfaces presents strong interfacial binding to resist mechanical and chemical peeling under harsh conditions and versatile surface functional groups to support various sequential surface chemical derivatizations, such as radical living graft polymerization, the electroless deposition of metals, biomineralization, and the facile synthesis of Janus particles and metal/protein capsules. Being distinct from other methods, the preparation of this pure protein coating under biocompatible conditions (e.g., neutral pH and nontoxic reagents) provides a reliable opportunity to directly modify living cell surfaces without affecting their biological activity. The PTL coating arms yeasts with a functional shell to protect their adhered body against foreign enzymatic digestion. The PTL coating further supports the surface immobilization of living yeasts for heterogeneous microbial reactions and the sequential surface chemical derivatization of the cell surfaces, e.g., radical living graft polymerization.
Few universal methods can functionalize particles of different compositions, sizes, shapes, and structures. This study describes the amyloid‐like protein‐assembly‐mediated surface modification and functionalization of particles and living colloids with different compositions, sizes, shapes, and structures. The establishment of this new surface engineering technique for particles and living cells can lead to a diverse array of tools for chemistry and materials.
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•An electrostatically confined method is developed for in-situ synthesis of CuNCs.•The preparation can be completed within 1 min without using any toxic agents.•CS-GSH-CuNCs shows ...much higher stability than GSH-CuNCs.•CS-GSH-CuNCs can be used as the fluorescence probe for detection of lysozyme.
The fundamental challenges in application of copper nanoclusters (CuNCs) to fluorescence sensing are their poor stability, weak fluorescence intensity, and time-consuming preparation. In this work, an efficient and green method was developed by using a positively charged natural polysaccharide, chitosan (CS), as confining agent to electrostatically trap the negatively charged glutathione (GSH) as reducing-cum-protecting ligand for the in-situ synthesis of CuNCs. The synthesis can be completed within 1 min and CS-GSH-CuNCs emits intense orange fluorescence with an emission peak at 574 nm, which is much higher than that of GSH-CuNCs prepared in the absence of CS. Meanwhile, owning to both confinement and antioxidant effects of CS, CS-GSH-CuNCs shows excellent stability against time, temperature, salt, UV irradiation, and pH. Furthermore, the emission intensity of CS-GSH-CuNCs can be quenched by lysozyme (Lys) through the enzymatic hydrolysis of CS by Lys. Based on that, a fluorescence method was developed for the Lys determination with a linear range of 5–110 nM and a detection limit of 1.6 nM. Moreover, this approach shows high selectivity to Lys over various common substances in the biological environment, and thus can be used to determine Lys in human serum.
In decades, anaerobic fermentation with short-chain fatty acids (SCFAs) recovery from excess sludge have attained rising attention. However, rigid particulate organic matter (POMs) structure with ...slow hydrolysis limited anaerobic fermentation performance of excess sludge. Remarkable sludge hydrolysis performance was supposed to be achievable by the synchronous EPS repture and microbial cell lysis. This study clarified the improvement of overall anaerobic fermentation performance by combination treatment of lysozyme (Lyso) catalysis and metal regulation (MR). The Lyso + MR treatment triggered EPS rupture by protein structure deflocculation while catalyzing microbial cell lysis, which promoted massive extracellular and intracellular POMs hydrolysis. As a result, a significant amount of SCOD (5646.67 mg/L) was produced. Such endogenous organic matters hydrolysis led to considerable SCFAs accumulation (3651.14 mg COD/L) through 48-h anaerobic fermentation at 1.75 g/g SS cation-exchange resin and Lyso dosage of 10% (w/w), which was 5.945 times higher than that in the control. Additionally, it suggested that most of the recovered SCFAs remained in fermentative liquid after chemical conditioning and mechanical dewatering towards solid-liquid separation, which provided considerable economic benefit of 363.6–1059.1 CNY/ton SS.
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•Extracellular and intracellular POMs were hydrolyzed by Lyso + MR treatment.•Lyso catalysis and MR treatment greatly promoted cell lysis and EPS rupture.•Considerable SCFAs of 3651 mg COD/L was produced by Lyso + MR assistant fermentation.•Satisfactory sludge dewaterability was achievable by chemical conditioning.•Engineering implications were expounded with economic benefits by SCFAs recovery.
Lysozymes are hydrolytic enzymes, and they are ubiquitous among all living organisms. They are mostly associated with antibacterial properties through their muramidase activity, while other ...properties such as iso-peptidase activity are also common. Invertebrate-type (i-type) lysozymes include the enzyme Destabilase, which is present in the salivary secretions of the medicinal leach Hirundo medicinalis. Destabilase has the ability to hydrolyse the ε-(γ-glutamyl)-lysine iso-peptide bonds formed by transglutaminase in fibrin of vertebrate blood, thereby destabilising blood clots.
We have identified an i-type lysozyme from the hemocytes of the freshwater crayfish Pacifastacus leniusculus, which was found to be upregulated at the protein level in response to an injection of the β-1,3-glucan laminarin. Based on its sequence we predicted that this lysozyme would lack muramidase activity, and therefore we decided to determine its putative immune function. The P. leniusculus i-type lysozyme (Pl-ilys), is a protein with 159 amino acid residues, including a 29 residue signal peptide, with a predicted molecular weight of 16 kDa and a predicted pI of 5.6. It is expressed primarily in the hemocytes and to a lesser extent in the hematopoietic tissue. A recombinant mature Pl-ilys using an E. coli expression system was produced, and we could ascertain that this enzyme was deficient of muramidase activity. Moreover, no iso-peptidase activity could be detected against the substrate l-γ-glutamine-p-nitroanilide. Analysis of the conserved domains in Pl-ilys showed a putative destabilase domain, and thus we tested the clot dissolving activity of this enzyme. We could show that the purified P. leniusculus clotting protein which had been coagulated and clotted with transglutaminase was dissolved by the addition of Pl-ilys. Taken together our results indicate that Pl-ilys has a clot dissolving or destabilising activity in crustacean blood.
•Pacifastacus leniusculus i-type lysozyme (Pl-ilys) is mainly expressed in hemocytes.•Pl-ilys is deficient of muramidase activity.•Pl-ilys is functioning as a clot degrading or destabilising enzyme.
Lysozyme (LYZ) c‐like proteins are primarily present in the testis and epididymis of male reproductive tissues. Here, we report a novel member of the c‐type LYZ family, the seminal vesicle‐secreted ...LYZ c‐like protein (SVLLP). Three forms of SVLLP were purified from mouse seminal vesicle secretions and characterized as glycoproteins with the same protein core but different N‐linked glycans. SVLLP is structurally similar to c‐type LYZ proteins. Only one of the 20 invariant residues was altered in the consensus sequence of c‐type LYZs; however, the changed residue (N53S) is one of two essential catalytic residues. LYZ activity assays demonstrated that the three glycoforms of SVLLP lacked enzyme activity. SVLLP is primarily expressed in seminal vesicles. Immunohistochemistry revealed that it occurs in the luminal fluid and mucosal epithelium of the seminal vesicles. Testosterone is not the primary regulator for its expression in the seminal vesicle. SVLLP binds to sperm and suppresses bovine serum albumin‐induced sperm capacitation, inhibits the acrosome reaction, and blocks sperm–oocyte interactions in vitro, suggesting that SVLLP is a sperm capacitation inhibitor.
We report a novel member of the c‐type lysozyme (LYZ) family, the seminal vesicle‐secreted LYZ c‐like protein (SVLLP). The change in one of the two essential catalytic residues causes SVLLP lack of LYZ activity. SVLLP is the first c‐type LYZ‐like protein that is not expressed in the testis or epididymis but predominantly expressed in seminal vesicles and involved in the inhibition of sperm capacitation in vitro.
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•The Na+ + Lysozyme pretreatment increased the yield of SCFAs in WAS by 7.6 times.•A synergistic effect was occurred between Na+ and lysozyme in promoting cell lysis.•Na+ + Lysozyme ...pretreatment significantly shortened the hydrolysis and acidification reaction times.•87% of the carbon source recovery in the liquid phase can be achieved after PAC conditioning.
Augmentation of the anaerobic treatment efficiency of waste activated sludge (WAS) to achieve better resource utilization is an effective approach for reducing carbon emissions and minimizing solid waste generation. However, resource recovery from WAS is often limited by the insufficient release and hydrolysis of organic matters within microbial cells. To overcome these issues, a novel Na+ and lysozyme co-pretreatment method has been used in this study to accelerate the production of short-chain fatty acids (SCFAs) by promoting cell lysis. Experimental results have revealed that the maximal SCFAs production of 302.8 ± 47.8 mg COD/g VSS is achieved with 10 % w/w lysozyme and 0.34 mol/L Na+ co-pretreatment on day 2, which is 7.6-fold higher than that of the control. Mechanism exploration has also exposed that Na+ and lysozyme exhibit a pronounced synergistic effect in cell lysis, where 1 + 1 > 2. The maximum sludge disintegration degree (DDM) and SCFAs conversion efficiency have been achieved by combined pretreatment, reaching 68.5 % and 74 %, respectively. The structure of extracellular polymeric substance (EPS) including protein content and looseness are also modified by Na+ or Na+ + Lysozyme pretreatment, which further confirm the impact of Na+ on the permeability of EPS. The carbon sources generated through Na+ and lysozyme pretreated WAS can be efficiently recovered through PAC conditioning, with a high recovery rate of 87 %. The Na+ and lysozyme reagents implemented in the present study are all non-toxic and cost-effective, thereby promising a green and efficient solution for the carbon recovery and separation from the WAS.
An assay that integrates histidine-rich peptides (HisRPs) with high-affinity aptamers was developed enabling the specific and sensitive determination of the target lysozyme. The enzyme-like activity ...of HisRP is inhibited by its interaction with a target recognized by an aptamer. In the presence of the target, lysozyme molecules progressively assemble on the surface of HisRP in a concentration-dependent manner, resulting in the gradual suppression of enzyme-like activity. This inhibition of HisRP’s enzyme-like activity can be visually observed through color changes in the reaction product or quantified using UV-visible absorption spectroscopy. Under optimal conditions, the proposed colorimetric assay for lysozyme had a detection limit as low as 1 nM and exhibited excellent selectivity against other nonspecific interferents. Furthermore, subsequent research validated the practical applicability of the developed colorimetric approach to saliva samples, indicating that the assay holds significant potential for the detection of lysozymes in samples derived from humans.
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•Lysozyme is immobilized on Ti3C2TX MXene nanosheets modified with polydopamine.•The light-switchable enzymatic antibacterial platform is constructed.•The antibacterial activity ...against MRSA improves after NIR light irradiation.
Being a unique biocatalyst to hydrolyse structural polysaccharides on the cell wall of bacteria, lysozyme can slow down bacterial resistance caused by antibiotic overdose treatments, however, efficient activation of lysozyme activities under pathogenic microenvironments remains challenging. Herein, a bio-interface engineering strategy was proposed for the remote modulation of thermoresistant lysozyme upon rationally designed photothermal nanoplatforms. For this, Ti3C2TX MXene nanosheets were functionalized by polydopamine (PDA) surface chemistry to enhance photothermal effects and performance durability, during which lysozyme biomacromolecules were immobilized at such a two-dimensional hybrid interface via intermolecular electrostatic affinity. The integrated nanoplatform (denoted as M@P@Lyso), with an optimal high light-to-heat conversion efficiency of 46.88%, realized not only precision control of local heat but also photo-responsive up-regulation for bio-catalysis of laden lysozyme. As a result, in vitro and in vivo antibacterial experiments revealed that M@P@Lyso could effectively inhibit the proliferation of methicillin-resistant Staphylococcus aureus and accelerated wound disinfection of mice with negligible biological toxicities. The outstanding antibacterial activities of M@P@Lyso were attributed to the photo-enhanced lysozyme activity, assisted by bacterial death caused by the mild local hyperthermia and the physical destruction derived from the M@PDA. This work exemplified a solution to the bacterial resistance threats via stimuli-responsive enzymatic nanoplatforms.
Complex coacervate is a classic charged polymer material in food science, personal care, and cellular biology. Nevertheless, time is often an important factor that is overlooked in the study of ...complex coacervates. This study analyzed the dynamic equilibrium/relaxation behavior of β-conglycinin/lysozyme (β-CG/LYS) heteroprotein coacervates after mixing, especially the effect of NaCl concentration, total protein concentration, and pH on this equilibrium behavior, only using two simple but effective methods (turbidity kinetics and bright-field microscopy). Although the turbidity kinetics of the β-CG/LYS coacervates experienced rapid initial growth like soluble complexes and amorphous precipitates, it subsequently showed a unique decline behavior. Through bright-field microscopy, we found that the drop in turbidity was closely related to the dynamic equilibrium of β-CG/LYS coacervates, including the shape-transformation from non-spherical clusters to spherical coacervates and the gradual merging of small coacervates. Adding NaCl (0, 20, and 40 mM), increasing the total protein concentration (1 and 5 mg/mL), and lowering pH (6 and 8) all accelerated the dynamic equilibrium of the β-CG/LYS coacervate and reduced the relaxation time. Turbidity kinetics can be used as a screening method to evaluate the effect of various factors on the dynamic equilibrium/relaxation behavior of coacervates.
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•The formation of coacervates followed two steps: fast assembly and slow equilibrium.•Dynamic equilibrium included shape-transformation and merging of small coacervates.•Kinetics trapped complex precipitates did not have dynamic equilibrium behaviors.•The decrease rate of turbidity reflected the tendency of dynamic equilibrium.
