Multiple Enzyme Activities Research Articles

Local Release of Copper Manganese Oxide Using HA Microneedle for Improving the Efficacy of Drug-Resistant Wound Inflammation.

The production of bacterial toxins and excessive accumulation of reactive oxygen species (ROS) can induce localized oxidative stress, triggering an exaggerated immune response that impedes wound healing and culminates in chronic wounds. To address this issue, a microneedle (MN) system loaded with copper-manganese oxide (CMO) is developed to modulate the hyperimmune response in wounds. CMO@MN exhibits excellent antimicrobial and anti-inflammatory properties by effectively killing bacteria, scavenging ROS, and modulating macrophage polarization through their multiple enzymatic activities and photothermal properties. RNA sequencing revealed that CMO@MN improved the therapeutic effect on the infected skin of mice by balancing the ratio of M1/M2 macrophages and promoting cell migration and angiogenesis through the regulation of relevant pathways. Overall, this CMO@MN patch skillfully balances the complex issues between the immune response and wound healing and has potential applications in the treatment of other serious bacterial infections.

NIR stimulated epigallocatechin gallate loaded polydopamine with enhanced antibacterial and ROS scavenging abilities for improved infectious wound healing

Infectious wound healing is complicated with and limited by infection and oxidative stress at the wound site. In recent years, various evidences suggest that nanozymes with multiple enzymatic activities have enabled the development of novel strategies for infectious wound healing. In this study, epigallocatechin gallate loaded polydopamine (P@E) was developed to act as a potent reactive oxygen species (ROS) scavenger for scavenging ROS, alleviating inflammatory responses, and promoting infectious wound healing. Combining with near infrared (NIR) irradiation, P@E presented excellent antibacterial ability of Escherichia coli (E. coli, 93.6%) and methicillin-resistant Staphylococcus aureus (MRSA, 87.6%). Specifically, P@E+NIR exhibited the most potent antioxidant, anti-inflammatory and cell proliferation behaviors through down-regulating intracellular ROS levels (81.9% and 94.3% for NIH3T3 and RAW264.7 respectively) and inducible nitric oxide synthase (iNOS) expression level (55.7%), and up-regulating the expression levels of arginase-1 (Arg-1, 71.4%), heat shock protein 70 (HSP70, 48.6%) and platelet endothelial cell adhesion molecule (CD31, 35.3%) compared to control group. Meanwhile, it also efficiently induced M2 directional polarization of lipopolysaccharide induced murine macrophages to achieve anti-inflammation, indicated by the down-regulation of CD86 (86.2%), and up-regulation of CD206 (85.6%). Significantly, it was also observed that P@E+NIR presented the excellent behaviors of inhibiting wound infection, alleviating wound inflammation, as well as promoting skin tissue repairing. Altogether, it has developed the strategy of using P@E combining with NIR irradiation for the synergistic enhanced healing of infectious skin wound, which can serve as a promising therapeutic strategy for its clinical treatment.

Size and crystallinity effects on enzymatic activity and anti-inflammatory properties of cysteine-assisted Prussian blue nanozymes

Prussian blue nanoparticles (PB NPs) exhibit multiple enzymatic activities, such as superoxide dismutase-like, catalase-like, and peroxidase-like activities, which enable them to effectively scavenge reactive oxygen species (ROS) and demonstrate anti-inflammatory effects. To further enhance the enzymatic activity of PB NPs, it is crucial to explore the relationship between their physicochemical properties, such as size and crystallinity, and their enzymatic performance. In this study, PB NPs were synthesized using different pH and varying concentrations of cysteine (Cys) as stabilizer. As the size decreases, crystallinity is gradually reduced, and defects increase. Cys-PB NPs with a smaller size and lower crystallinity exhibited high peroxidase-like activity, effectively reducing inflammation and scavenging intracellular ROS in vitro. Additionally, the stability of Cys-PB NPs plays a critical role in their anti-inflammatory properties, with higher stability favouring anti-inflammatory effect.

Boosting Tumor Apoptosis and Ferroptosis with Multienzyme Mimetic Au Single‐Atom Nanozymes Engaged in Cascade Catalysis

AbstractNanozyme‐based catalytic therapy has garnered much attention in cancer treatment for converting endogenous substrates into reactive oxygen species (ROS), which induce oxidative stress damage in tumors. However, the effectiveness of nanozymes is hindered by the limited availability of these endogenous substrates in the tumor microenvironment. To address this, a novel gold‐based single‐atom nanozyme (AuSAN), glucose oxidase (GOx, G), and lactate oxidase (LOx, L) are meticulously engineered into a highly ordered biomimetic composite nanozyme M/GLB@AuSAN, forming an interconnected cascade catalysis that catalyzes the carbon sources of tumor into ROS as a sustained antitumor strategy. The loaded GOx and LOx aerobically catalyze glucose and lactate to produce H2O2, which is then rapidly converted into ·OH, O2•−, and O2 by AuSAN. The generated O2 serves as a positive feedback substrate for further GOx‐ and LOx‐mediated aerobic catalysis, significantly amplifying cascade catalysis, and thereby enhancing ROS accumulation. The abundant intracellular ROS and scarce carbon sources effectively exacerbate protein phosphorylation, lipid peroxidation, and mitochondrial damage, ultimately provoking tumor apoptosis and ferroptosis in vitro and in vivo. Therefore, the integrated design of GOx/LOx/AuSAN provides a promising strategy to combine multiple enzymatic activities, deplete carbon sources, and enhance ROS production, resulting in the suppression of melanoma progression.

Peroxiredoxin 6 (Prx6) of Penaeus vannamei and effect of phenanthrene on Prx6 and glutathione peroxidase 4 expression, glutathione-dependent peroxidase activity and lipid peroxidation

Polycyclic aromatic hydrocarbons (PAHs), such as phenanthrene (PHE), are common pollutants found in coastal areas where shrimp farming is developed. Even though PAHs can have adverse effects on physiology, shrimp can detoxify and metabolize toxic compounds and neutralize the reactive oxygen species (ROS) produced during this process. This requires the activation of multiple antioxidant enzymes, including peroxiredoxin 6 (Prx6). Prx6 uses glutathione (GSH) to reduce phospholipid hydroperoxides, a function shared with GSH peroxidase 4 (GPx4). Prx6 has been scarcely studied in crustaceans exposed to pollutants. Herein, we report a novel Prx6 from the shrimp Penaeus vannamei that is abundantly expressed in gills and hepatopancreas. To elucidate the involvement of Prx6 in response to PAHs, we analyzed its expression in the hepatopancreas of shrimp sub-lethally exposed to PHE (3.3 μg/L) and acetone (control) for 24, 48, 72, and 96 h, along with GPx4 expression, GSH-dependent peroxidase activity, and lipid peroxidation (indicated by TBARS). We found that GPx4 expression is not affected by PHE, but Prx6 expression and peroxidase activity decreased during the trial. This might contribute to the rise of TBARS found at 48 h of exposure. However, maintaining GPx4 expression could aid to minimize lipid damage during longer periods of exposure to PHE.

Defect engineering synergistically boosts the catalytic activity of Fe-MoOv for highly efficient breast mesh antitumor therapy

The demand for breast mesh with antitumor properties is critical in post-mastectomy breast reconstruction to prevent local tumor recurrence. Molybdenum-based oxide (MoOx) exhibits enzyme-like activities by catalyzing endogenous hydrogen peroxide to produce reactive oxygen species for inducing tumor cell apoptosis. However, its catalytic activity is limited by insufficient active sites. Herein, a defect engineering strategy is proposed to create redox nanozymes with multiple enzymatic activities by incorporating Fe into MoOx (Fe-MoOv). Fe-MoOv is subsequently integrated into polycaprolactone (PCL) to fabricate breast meshes for establishing an enzyme-catalyzed antitumor platform. The doping of Fe into MoOx formed numerous defect sites, including oxygen vacancies (OV) and Fe substitution sites, synergistically boosting the binding capacity and catalytic activity of Fe-MoOv. Density functional theory calculations demonstrated that the outstanding peroxidase-like catalytic activity of Fe-MoOv resulted from the synergy between OV and Fe sites. Additionally, OV contributes to the localized surface plasmon resonance effect, enhancing the photothermal capability of the PCL/Fe-MoOv mesh. Upon near-infrared laser exposure, the catalytic activity of the PCL/Fe-MoOv mesh is further improved, leading to increased generation of reactive oxygen species and enhanced antitumor efficacy, achieving 86.7% tumor cell mortality, a 264% enhancement compared to the PCL/MoOx mesh.

Transparent coating based on multienzyme-mimicking Janus nanozyme for synergetic biofouling control in seawater

The problem of marine biofouling persists in marine resource development, particularly for marine observation. While nanomaterials with enzyme-mimicking activity show promise in combating marine biofouling, their unique physicochemical properties that enable nanozymes with multiple enzymatic activities for a synergetic antifouling effect have yet to be explored. Here, it is shown that a transparent zwitterionic coating based on Ag/Ag2S Janus nanoparticles (Ag/Ag2S JNPs) with peroxidase-, light-activated oxidase-, and haloperoxidase-mimicking activities contributes to antifouling synergy. The mechanism of the nanozyme action is revealed in a detailed experimental and computational study, in which unique Janus structures guarantee multi-enzyme-mimicking properties and produce OH, HOBr, and O2− to combat biofouling. Through the formation of hydration layers, zwitterionic coatings further enhance this antifouling capacity, as demonstrated by both indoor and outdoor marine field antifouling tests. Consequently, a coating like this shows a clear transmittance and excellent antifouling ability after 90 days in marine immersion, reducing fouling by 74.91 % and 39.71 % compared to a control coating and a commercial coating, respectively. This study not only demonstrates synergetic antifouling actions via multi-enzyme-mimicking activities but also uncovers a new paradigm in nanozyme-based environmentally friendly, sustainable antifouling strategy.

Biochar Application in Combination with No Tillage Enhanced Yield and Grain Quality of Ratoon Rice

Biochar is beneficial as a clean, stable, and efficient soil amendment to improve rice quality and yield. However, there are few reports on the effects of no-tillage in combination with biochar application on rice growth, yield, and quality in regenerative rice systems. This study evaluated rice yield, grain quality, multiple antioxidant enzyme activities, and malondialdehyde content under four treatments: rotary tillage alone, rotary tillage + biochar application, no-tillage alone, and no-tillage + biochar. The results showed that the rice yield under no-tillage alone was 15% lower than that under rotary tillage alone, but that biochar application significantly increased rice yield by 10% and 20% under rotary tillage and no-tillage conditions, respectively, which might be attributed to the fact that biochar application increased panicle number, spikelet number per panicle, grain filling rate, and antioxidant enzyme activities. Additionally, biochar application also increased fine rice rate and protein content, meanwhile reducing chalkiness degree and chalky grain rate in both the main-season rice and ratoon-season rice. These results suggest that biochar application could enhance the yield and grain quality of ratoon rice, thus compensating for the no-tillage-induced yield loss. This study reveals the role of biochar in main-season rice and ratoon rice cultivation, providing a valuable reference for improved fertilizer utilization and cleaner agricultural production.

Light-Controlled Regulation of Dual-Enzyme Properties in YbGd-Carbon Quantum Dots Nano-Hybrid for Advanced Biosensing.

Compared to nanozymes with single enzyme activity, those with multiple enzyme activities possess broader application potential due to their diversified enzymatic functionalities. However, the multienzyme nanozymes currently face challenges of interference among different enzymatic activities during practical applications. In this study, we report the synthesis of a light-responsive YbGd-carbon quantum dots nano-hybrid, termed YbGd-CDs, which exhibits controllable enzyme-mimicking activities. This light-responsive behavior enables selective control of the enzymatic activities. Under visible light irradiation, YbGd-CDs demonstrate robust oxidase-like activity. Conversely, under dark conditions, they primarily exhibit peroxidase-like activity. Leveraging the dual-enzyme-mimicking capabilities of YbGd-CDs, we developed colorimetric assays for sensitive detection of total antioxidant capacity (TAC) in both normal and cancer cells as well as d-amino acids in human saliva. This study not only advances the synthesis of carbon-based nanozymes but also highlights their potential in biosensing applications.

Dual-enhanced enzyme cascade hybrid hydrogel for the construction of optical biosensor

The biomimetic enzyme cascade system plays a key role in biosensing as a sophisticated signal transduction and amplification strategy. However, constructing a regulated enzyme cascade sensing system remains challenging due to the mismatch of multiple enzyme activities and poor stability. Herein, we design an efficient dual-enhanced enzyme cascade hybrid system (UFD-DEC) containing DNA-controlled nanozymes (Fe-cdDNA) and enzyme (urease) via combining the electrostatic contact effect with the hydrogel-directed confinement effect. Precise modulation of Fe-cdDNA nanozyme by DNA offers a means to control its catalytic efficiency. This regulated UFD-DEC system accelerates the reaction rate and provides remarkable stability compared with the free enzyme system. Benefiting from the plasticity properties of hydrogels, a “lab-in-a-tube” platform was constructed by encapsulating UFD-DEC in a microcentrifuge tube. Such a UFD-DEC-based hydrogel tube exhibits sufficient adaptability to profile urea when used in conjunction with a smartphone-assisted image processing algorithm, which on-site delivers urea information with a detection limit of 0.12 mmol L−1. This customizable and inexpensive miniaturized biosensor platform for monitoring urea may facilitate point-of-care testing applications.

Fabrication of Nanocatalytic Medicine from Self-Assembling Peptides Containing an ATCUN-Like Copper-Binding Motif for Anticancer Therapy.

Development of nanomaterials with multiple enzymatic activities via a facile approach receives growing interests in recent years. Although peptide self-assembling provides an effective approach for the construction of biomimetic materials in recent years, fabrication of artificial enzymes from self-assembling peptides with multiple catalytic activities for anticancer therapy is still a challenge. Here, we report a simple method to prepare nanocatalysts with multienzyme-like activities from self-assembling peptides containing ATCUN copper-binding motifs. With the aid of the coordination interactions between the ATCUN motif and Cu(II) ions, these peptides could perform supramolecular self-assembly to form nanomaterials with biomimetic peroxidase, ascorbate oxidase and glutathione peroxidase activities. Moreover, these trienzyme-like effects can elevate oxidative stress levels and suppress the antioxidative capability of cancer cells, which synergistically induce the apoptosis of cancer cells. Because of the high biocompatibility, catalytic activities and drug encapsulation properties, this self-assembled peptide provides a biomimetic platform for the development of new nanocatalytic medicines for multimodal synergistic cancer therapies.

A Programmable Microfluidic Paper-Based Analytical Device for Simultaneous Colorimetric and Photothermal Visual Sensing of Multiple Enzyme Activities.

New strategies for the simultaneous and portable detection of multiple enzyme activities are highly desirable for clinical diagnosis and home care. However, the methods developed thus far generally suffer from high costs, cumbersome procedures, and heavy reliance on large-scale instruments. To satisfy the actual requirements of rapid, accurate, and on-site detection of multiple enzyme activities, we report herein a smartphone-assisted programmable microfluidic paper-based analytical device (μPAD) that utilizes colorimetric and photothermal signals for simultaneous, accurate, and visual quantitative detection of alkaline phosphatase (ALP) and butyrylcholinesterase (BChE). Specifically, the operation of this μPAD sensing platform is based on two sequential steps. Cobalt-doped mesoporous cerium oxide (Co-m-CeO2) with remarkable peroxidase-like activities under neutral conditions first catalytically decomposes H2O2 for effectively converting colorless 3,3',5,5'-tetramethylbenzidine (TMB) into blue oxidized TMB (oxTMB). The subsequent addition of ALP or BChE to their respective substrates produces a reducing substance that can somewhat inhibit the oxTMB transformation for compromised colorimetric and photothermal signals of oxTMB. Notably, these two-step bioenzyme-nanozyme cascade reactions strongly support the straightforward and excellent processability of this platform, which exhibit lower detection limits for ALP and BChE with a detection limit for BChE an order of magnitude lower than those of the other reported paper-based detection methods. The practicability and efficiency of this platform are further demonstrated through the analysis of clinical serum samples. This innovative platform exhibits great potential as a facile yet robust approach for simultaneous, accurate, and on-site visual detection of multiple enzyme activities in authentic samples.

Ultrasmall CuMn-His Nanozymes with Multienzyme Activity at Neutral pH: Construction of a Colorimetric Sensing Array for Biothiol Detection and Disease Identification.

Biothiol assays offer vital insights into health assessment and facilitate the early detection of potential health issues, thereby enabling timely and effective interventions. In this study, we developed ultrasmall CuMn-Histidine (His) nanozymes with multiple enzymatic activities. CuMn-His enhanced peroxidase (POD)-like activity at neutral pH was achieved through hydrogen bonding and electrostatic effects. In addition, CuMn-His possesses laccase (LAC)-like and superoxide dismutase (SOD)-like activities at neutral pH. Based on three different enzyme mimetic activities of CuMn-His at neutral pH, the colorimetric sensing array without changing the buffer solution was successfully constructed. The array was successfully used for the identification of three biothiols, glutathione (GSH), cysteine (Cys), and homocysteine (Hcy). Subsequently, excellent application results were shown in complex serum and cellular level analyses. This study provides an innovative strategy for the development of ultrasmall bimetallic nanozymes with multiple enzymatic activities and the construction of colorimetric sensing arrays.

Identification and evaluation of an endophytic antagonistic yeast for the control of gray mold (Botrytis cinerea) in apple and mechanisms of action

Gray mold, caused by Botrytis cinerea, is a prevalent postharvest disease of apple that limits their shelf life, resulting in significant economic losses. The use of antagonistic microorganisms has been shown to be an effective approach for managing postharvest diseases of fruit. In the present study, an endophytic yeast strain PGY-2 was isolated from apples and evaluated for its biocontrol efficacy against gray mold and its mechanisms of action. Results indicated that strain PGY-2, identified as Bullera alba, reduced the occurrence of gray mold on apples and significantly inhibited lesion development in pathogen-inoculated wounds. Gray mold control increased with the use of increasing concentrations of PGY-2, with the best disease control observed at 108 cells/mL. Notably, Bullera alba PGY-2 did not inhibit the growth of Botrytis cinerea in vitro indicating that the yeast antagonist did not produce antimicrobial compounds. The rapid colonization and stable population of PGY-2 in apple wounds at 4 °C and 25 °C confirmed its ability to compete with pathogens for nutrients and space. PGY-2 also had a strong ability to form a biofilm and enhanced the activity of multiple defense-related enzymes (POD, PPO, APX, SOD, PAL) in host tissues. Our study is the first time to report the use of Bullera alba PGY-2 as a biocontrol agent for postharvest diseases of apple and provide evidence that Bullera alba PGY-2 represents an endophytic antagonistic yeast with promising biocontrol potential and alternative to the use of synthetic, chemical fungicides for the control of postharvest gray mold in apples.

CuCo2O4 Nanoflowers with Multiple Enzyme Activities for Treating Bacterium-Infected Wounds via Cuproptosis-like Death.

Nanozyme-driven catalytic therapy provides a promising treatment strategy for bacterial biofilm-infected wounds. However, the single functionality and limited catalytic efficiency of nanozyme-based materials often restrict the effectiveness of wound infection treatment. In this study, CuCo2O4 nanoflowers with multiple enzymatic activities were prepared for antibacterial/antibiofilm treatment by cuproptosis-like death. CuCo2O4 exhibited peroxidase-like (POD-like) and oxidase-like (OXD-like) dual enzyme activities that generated large amounts of •OH and O2•-. Moreover, the glutathione peroxidase-like (GSH-Px-like) activity of CuCo2O4 was able to reduce the overexpression of GSH in the wound microenvironment, enhancing the therapeutic effects of reactive oxygen species (ROS). The morphology of CuCo2O4 was modified using a hydrothermal method with PEG4000 as the solvent, resulting in the exposure of more active center sites and a significant improvement in enzyme catalytic activity. The in vitro results demonstrated the pronounced disruption effect of CuCo2O4 on biofilms formed by bacteria. In vivo, CuCo2O4 significantly promoted angiogenesis, collagen deposition, and cell proliferation. Transcriptome sequencing revealed that elevated ROS levels in bacteria led to cell membrane damage and metabolic disruption. In addition, Cu2+ overload in bacteria induces lipid peroxidation accumulation and disrupts the respiratory chain and tricarboxylic acid (TCA) cycle, ultimately leading to bacterial cuproptosis-like death. This therapeutic strategy, which combines the synergistic effects of multiple enzyme-like activities with cuproptosis-like death, provides an approach for treating biofilm infections.

Sequential Regulation of Local Reactive Oxygen Species by Ir@Cu/Zn-MOF Nanoparticles for Promoting Infected Wound Healing.

Most antimicrobials treat wound infections by an oxidation effect, which is induced by the generation of reactive oxygen species (ROS). However, the potential harm of the prolonged high level of ROS should not be ignored. In this study, we presented a novel cascade-reaction nanoparticle, Ir@Cu/Zn-MOF, to effectively regulate the ROS level throughout the healing progress of the infected wound. The nanoparticles consisted of a copper/zinc-modified metal-organic framework (Cu/Zn-MOF) serving as the external structure and an inner core composed of Ir-PVP NPs, which were achieved through a process known as "bionic mineralization". The released Cu2+ and Zn2+ from the shell structure contributed to the production of ROS, which acted as antimicrobial agents during the initial stage. With the disintegration of the shell, the Ir-PVP NP core was gradually released, exhibiting the property of multiple antioxidant enzyme activities, thereby playing an important role in clearing excessive ROS and alleviating oxidative stress. In a full-layer infected rat wound model, Ir@Cu/Zn-MOF nanoparticles presented exciting performance in promoting wound healing by clearing the bacteria and accelerating neovascularization as well as collagen deposition. This study provided a promising alternative for the repair of infected wounds.

Sirtuin 5 alleviates apoptosis and autophagy stimulated by ammonium chloride in bovine mammary epithelial cells.

Ammonia (NH3) is an irritating and harmful gas that affects cell apoptosis and autophagy. Sirtuin 5 (SIRT5) has multiple enzymatic activities and regulates NH3-induced autophagy in tumor cells. In order to determine whether SIRT5 regulates NH3-induced bovine mammary epithelial cell apoptosis and autophagy, cells with SIRT5 overexpression or knockdown were generated and in addition, bovine mammary epithelial cells were treated with SIRT5 inhibitors. The results showed that SIRT5 overexpression reduced the content of NH3 and glutamate in cells by inhibiting glutaminase activity in glutamine metabolism, and reduced the ratio of ADP/ATP. The results in the SIRT5 knockdown and inhibitor groups were comparable, including increased content of NH3 and glutamate in cells by activating glutaminase activity, and an elevated ratio of ADP/ATP. It was further confirmed that SIRT5 inhibited the apoptosis and autophagy of bovine mammary epithelial cells through reverse transcription-quantitative PCR, western blot, flow cytometry with Annexin V FITC/PI staining and transmission electron microscopy. In addition, it was also found that the addition of LY294002 or Rapamycin inhibited the PI3K/Akt or mTOR kinase signal, decreasing the apoptosis and autophagy activities of bovine mammary epithelial cells induced by SIRT5-inhibited NH3. In summary, the PI3K/Akt/mTOR signal involved in NH3-induced cell autophagy and apoptosis relies on the regulation of SIRT5. This study provides a new theory for the use of NH3 to regulate bovine mammary epithelial cell apoptosis and autophagy, and provides guidance for improving the health and production performance of dairy cows.

Abstract 3095: Characterization Of Interactions Between Skeletal Muscle Myosin And Activated Factor XI

Background: We recently demonstrated that the procoagulant activity of skeletal muscle myosin (SkM) involved the binding of coagulation factor (F) XI to enhance FXI activation by thrombin. However, the impact of SkM on the enzymatic activities of activated FXI (FXIa) remains unclear. Aims: Determine the influence of SkM interactions on the expression of FXIa activities. Methods: Binding studies between FXIa and SkM were conducted using biolayer interferometry (BLI). Kallikrein, a FXIa homolog, served as a negative control. The interactions between SkM and FXIa were investigated through fluorescence spectroscopy using dansyl-labeled FXIa. Chromogenic assays for FXIIa were employed to measure FXII activation by FXIa. Tissue factor pathway inhibitor (TFPI) inactivation by FXIa was assessed by determining FXa inhibition by TFPI using FX chromogenic assays. Quantification of complement factor H (CFH) cleavage by FXIa as well as FV activation by FXIa were carried out using SDS PAGE and Coomassie blue staining. Results: BLI data showed that SkM exhibited a high binding affinity for FXIa with a dissociation constant of 1.6 nM, whereas SkM did not bind kallikrein. The addition of SkM induced a 9 nm shift in the emission spectrum of dansyl-labeled FXIa. The presence of SkM increased the rate of feedback FXII activation by FXIa but not by kallikrein. The addition of SkM inhibitors, trifluoperazine and blebbistatin, reduced the enhancement effect of SkM on the ability of FXIa to activate FXII. Furthermore, SkM increased the rate of enzymatic inactivation of TFPI by FXIa, the rate of cleavage of CFH by FXIa, and the rate of activation of FV by FXIa. Conclusions: SkM binds with high affinity to FXIa and serves as a co-factor to enhance multiple different enzymatic activities of FXIa. Future work is needed to examine the multiple procoagulant activities of SkM in the setting of hemostasis and acute trauma.

Fluorinated complexes doped nanodot with high brightness and dual emission for ratiometric detection of glucose-related enzymes

Fluorescence detection of enzymes have attracted considerable interest due to their promise in biological applications, while suffering from the limitation of rigorous demand on the structure design of enzyme substrates. Herein, we report a simple and convenient approach for fluorescence detection of multiple enzymes by developing a fluorescence/phosphorescence dual-emissive nanodot, which is composed of fluorinated organic dyes and fluorinated Pt (II) porphyrin complexes, and exhibits ratiometric luminescence response toward oxygen. We characterized the optical properties of the nanodot, which showed high brightness and sensitive oxygen-response luminescence. Based on the oxygen-consumed enzymatic reaction of glucose oxidase and the glucose-generated enzymatic reaction of the enzymes related to glucose metabolism, and using this presented nanodot, the concentration of glucose and the enzymatic activity of invertase, β-galactosidase, and maltase in aqueous solution were successfully determined quantitatively. To the best of our knowledge, the strategy proposed here for enzyme detection is the first demonstration of an optical probe for monitoring the enzymatic activity of multiple enzymes. Significantly, the strategy presented here may provide a general design principle to develop a kind of luminescent probe for detecting various enzymes.

Production of Conjugated Linoleic Acid (CLA) by Lactiplantibacillus plantarum: A Review with Emphasis on Fermented Foods.

The term Conjugated Linoleic Acid (CLA) refers generically to a class of positional and geometric conjugated dienoic isomers of linoleic acid. Among the isomers of linoleic acid cis9, trans11-CLA (c9, t11-CLA) and trans10, cis12-CLA (t10, c12-CLA) are found to be biologically active isomers, and they occur naturally in milk, dairy products and meat from ruminants. In addition, some vegetables and some seafoods have also been reported to contain CLA. Although the CLA levels in these natural sources are insufficient to confer the essential health benefits, anti-carcinogenic or anti-cancer effects are of current interest. In the rumen, CLA is an intermediate of isomerization and the biohydrogenation process of linoleic acid to stearic acid conducted by ruminal microorganisms. In addition to rumen bacteria, some other bacteria, such as Propionibacterium, Bifidobacterium and some lactic acid bacteria (LAB) are also capable of producing CLA. In this regard, Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) has demonstrated the ability to produce CLA isomers from linoleic acid by multiple enzymatic activities, including hydration, dehydration, and isomerization. L. plantarum is one of the most versatile species of LAB and the bacterium is widely used in the food industry as a microbial food culture. Thus, in this review we critically analyzed the literature produced in the last ten years with the aim to highlight the potentiality as well as the optimal conditions for CLA production by L. plantarum. Evidence was provided suggesting that the use of appropriate strains of L. plantarum, as a starter or additional culture in the production of some fermented foods, can be considered a critical factor in the design of new CLA-enriched functional foods.