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ACS Omega Jun 2024Water electrolysis for clean hydrogen production requires high-activity, high-stability, and low-cost catalysts for its particularly sluggish half-reaction, the oxygen...
Water electrolysis for clean hydrogen production requires high-activity, high-stability, and low-cost catalysts for its particularly sluggish half-reaction, the oxygen evolution reaction (OER). Currently, the most promising of such catalysts working in alkaline conditions is a core-shell nanostructure, NiFe@NC, whose Fe-doped Ni (NiFe) nanoparticles are encapsulated and interconnected by N-doped graphitic carbon (NC) layers, but the exact OER mechanism of these catalysts is still unclear, and even the location of the OER active site, either on the core side or on the shell side, is still debated. Therefore, we herein derive a plausible active-site model for each side based on various experimental evidence and density functional theory calculations and then build OER free-energy diagrams on both sides to determine the active-site location. The core-side model is an FeO-type (rather than NiO-type) active site where an Fe atom sits on Ni oxide layers grown on top of the core surface during catalyst activation, whose facile dissolution provides an explanation for the activity loss of such catalysts directly exposed to the electrolyte. The shell-side model is a NiN-type (rather than FeN-type) active site where a Ni atom is intercalated into the porphyrin-like NC site of the NC shell during catalyst synthesis. Their OER free-energy diagrams indicate that both sites require similar amounts of overpotentials, despite a complete shift in their potential-determining steps, i.e., the final O evolution from the oxophilic Fe on the core and the initial OH adsorption to the hydrophobic shell. We conclude that the major active sites are located on the core, but the NC shell not only protects the vulnerable FeO active sites on the core from the electrolyte but also provides independent active sites, owing to the N doping.
PubMed: 38911812
DOI: 10.1021/acsomega.3c09920 -
International Journal of Biological... Jun 2024Chitosan/zeolite-X (CHS/ZX) was synthesized to serve as an effective adsorbent for metal porphyrins through adsorption processes as an alternative to traditional...
Chitosan/zeolite-X (CHS/ZX) was synthesized to serve as an effective adsorbent for metal porphyrins through adsorption processes as an alternative to traditional separation methods from crude oil. The adsorption-desorption mechanisms of vanadyl and nickel tetraphenyl porphyrin (VO-TPP and Ni-TPP) were conducted on the model solution. Compared to individual components CHS and ZX, the CHS/ZX composite exhibited a doubled capacity for metal porphyrin removal. The synthesized composite was systematically characterized using FESEM, BET, XRD, FTIR, TGA, XPS, and CHN analyses. The study investigated the impact of many factors, including temperature, initial metal-porphyrin concentration, CHS/ZX dose, and contact time, on the adsorption efficiency of metal-porphyrin using CHS/ZX adsorbents. The adsorption processes of VO-TPP and Ni-TPP on CHS/ZX were effectively assessed through various equilibrium models, such as Langmuir, Freundlich, and Dubinin-Radushkevich (D-R). The pseudo-second-order model accurately depicted the adsorption processes of both VO-TPP and Ni-TPP. Determining the point of zero charge (pH) highlighted the composite's surface charge distribution. Furthermore, considering the ΔG° and ΔH° values, the adsorption processes at different temperatures are exothermic, and VO-TPP exhibits a greater adsorption capacity than Ni-TPP under similar conditions. Notably, 73.7 % of VO-TPP and 83.8 % of Ni-TPP that were adsorbed were successfully recovered.
PubMed: 38909734
DOI: 10.1016/j.ijbiomac.2024.133358 -
Biosensors & Bioelectronics Oct 2024An electrochemical (EC) sensor based on metalloporphyrin metal-organic framework (MOF) for the detection of parathion-methyl (PM) has been developed. The prepared...
An electrochemical (EC) sensor based on metalloporphyrin metal-organic framework (MOF) for the detection of parathion-methyl (PM) has been developed. The prepared MOF-525(Fe) exhibits great signal enhancement toward the electrochemical detection of PM owing to its unique structural properties and electrochemical activities. Under optimal experimental conditions, the as-prepared MOF-525(Fe) based EC sensor exhibited excellent PM sensing performance with a wide linear detection range (0.1 μM-100 μM) and low limit of detection (LOD, 1.4 nM). Compared to its corresponding Fe metalloporphyrin (linker), MOF-525(Fe) exhibited a superior sensitivity (28.31 μA cm·μM), which is 3.7 times higher than the sensitivity of FeTCPP linker (7.56 μA cm·μM) towards PM. The improved performance is associated with the high specific surface area and the large pore channels of MOF-525(Fe) facilitating a better interaction between PM and the Fe metalloporphyrin active sites, especially in the lower concentration range. Moreover, a possible affinity of the PM molecules toward Zr clusters may also contribute to the selective enrichment of PM on MOF-525(Fe). This EC sensor further demonstrated high selectivity in the presence of interfering molecules. The recovery results further confirm accurate PM sensing in actual samples, which suggests promising applications for the rapid detection of environmental organophosphates by metalloporphyrin MOFs.
Topics: Metal-Organic Frameworks; Electrochemical Techniques; Biosensing Techniques; Metalloporphyrins; Limit of Detection; Zirconium; Methyl Parathion
PubMed: 38909444
DOI: 10.1016/j.bios.2024.116515 -
TAG. Theoretical and Applied Genetics.... Jun 2024A large fragment deletion of CpAPRR2, encoding a two-component response regulator-like protein, which influences immature white rind color formation in zucchini...
A large fragment deletion of CpAPRR2, encoding a two-component response regulator-like protein, which influences immature white rind color formation in zucchini (Cucurbita pepo). Fruit rind color is an important agronomic trait that affects commodity quality and consumer choice in zucchini (Cucurbita pepo). However, the molecular mechanism controlling rind color is unclear. We characterized two zucchini inbred lines: '19' (dark green rind) and '113' (white rind). Genetic analysis revealed white immature fruit rind color to be controlled by a dominant locus (CpW). Combining bulked segregant analysis sequencing (BSA-seq) and Kompetitive Allele-Specific PCR (KASP) markers, we mapped the CpW locus to a 100.4 kb region on chromosome 5 and then narrow down the candidate region to 37.5 kb using linkage analysis of 532 BC and 1613 F individuals, including 6 coding genes. Among them, Cp4.1LG05g02070 (CpAPRR2), encoding a two-component response regulator-like protein, was regarded to be a promising candidate gene. The expression level of CpAPRR2 in dark green rind was significantly higher than that in white rind and was induced by light. A deletion of 2227 bp at the 5' end of CpAPRR2 in '113' might explain the white phenotype. Further analysis of allelic diversity in zucchini germplasm resources revealed rind color to be associated with the deletion of CpAPRR2. Subcellular localization analysis indicated that CpAPRR2 was a nuclear protein. Transcriptome analysis using near-isogenic lines with dark green (DG) and white (W) rind indicated that genes involved in photosynthesis and porphyrin metabolism pathways were enriched in DG compared with W. Additionally, chlorophyll synthesis-related genes were upregulated in DG. These results identify mechanisms of zucchini rind color and provide genetic resources for breeding.
Topics: Fruit; Chromosome Mapping; Pigmentation; Phenotype; Cucurbita; Plant Proteins; Genetic Linkage; Gene Expression Profiling; Gene Expression Regulation, Plant; Alleles; Genes, Plant; Color; Transcriptome
PubMed: 38909110
DOI: 10.1007/s00122-024-04676-z -
Bioorganic Chemistry Jun 2024LD4, a novel porphyrin derivative, has attracted much attention for its excellent anti-inflammatory properties. It can promote the healing of colonic mucosa, reduce...
LD4, a novel porphyrin derivative, has attracted much attention for its excellent anti-inflammatory properties. It can promote the healing of colonic mucosa, reduce inflammatory response, regulate oxidative stress, and thus improve ulcerative colitis (UC) symptoms. However, the specific signaling pathways of LD4-PDT involved in UC have not been explored. The present study aimed to elucidate the effects of LD4 on UC and to investigate the underlying mechanisms both in vivo and in vitro. We classified and screened the LD4-PDT proteomic data to obtain key targets. Proteomic data revealed that EPHX2 and STAT3 are key targets of LD4-PDT for UC. Moreover, transcription factor STAT3 positively regulates the expression of EPHX2. Inhibiting EPHX2 can prevent the activation of NF-κB signaling pathway. Next, through pharmacological inhibition experiments, we confirmed that LD4-PDT can reduce intestinal inflammation by inhibiting STAT3-EPHX2 axis. However, by treating normal intestinal epithelial cells and colon cancer cells with TPPU and Stattic, our data confirmed that the STAT3-EPHX2 axis does not exist in colon cancer. In this study, we demonstrated that the transcription factor STAT3 can positively regulate the expression of EPHX2 in normal colon. LD4 can alleviate UC by inhibiting the STAT3-EPHX2 axis, but this axis does not exist in colon cancer. LD4-PDT may become a new and effective method for treating UC.
PubMed: 38908128
DOI: 10.1016/j.bioorg.2024.107579 -
Journal of Nanobiotechnology Jun 2024Hypoxia-activated prodrug (HAP) is a promising candidate for highly tumor-specific chemotherapy. However, the oxygenation heterogeneity and dense extracellular matrix...
BACKGROUND
Hypoxia-activated prodrug (HAP) is a promising candidate for highly tumor-specific chemotherapy. However, the oxygenation heterogeneity and dense extracellular matrix (ECM) of tumor, as well as the potential resistance to chemotherapy, have severely impeded the resulting overall efficacy of HAP.
RESULTS
A HAP potentiating strategy is proposed based on ultrasound responsive nanodroplets (PTP@PLGA), which is composed of protoporphyrin (PpIX), perfluoropropane (PFP) and a typical HAP, tirapazamine (TPZ). The intense vaporization of PFP upon ultrasound irradiation can magnify the sonomechanical effect, which loosens the ECM to promote the penetration of TPZ into the deep hypoxic region. Meanwhile, the PpIX enabled sonodynamic effect can further reduce the oxygen level, thus activating the TPZ in the relatively normoxic region as well. Surprisingly, abovementioned ultrasound effect also results in the downregulation of the stemness of cancer cells, which is highly associated with drug-refractoriness.
CONCLUSIONS
This work manifests an ideal example of ultrasound-based nanotechnology for potentiating HAP and also reveals the potential acoustic effect of intervening cancer stem-like cells.
Topics: Humans; Tirapazamine; Protoporphyrins; Fluorocarbons; Prodrugs; Cell Line, Tumor; Nanoparticles; Neoplastic Stem Cells; Antineoplastic Agents; Ultrasonic Waves; Animals; Extracellular Matrix; Mice; Neoplasms
PubMed: 38907270
DOI: 10.1186/s12951-024-02623-0 -
Bioorganic & Medicinal Chemistry Jul 2024The antimicrobial activity of new acid-functionalized porphyrins, with or without ultra-high irradiance, was investigated. Antibacterial efficacy was evaluated against...
Synthesis and characterization of new acid-functionalized porphyrins displaying antimicrobial activity against gram positive bacteria, yeasts and filamentous fungi with or without ultra-high irradiance.
The antimicrobial activity of new acid-functionalized porphyrins, with or without ultra-high irradiance, was investigated. Antibacterial efficacy was evaluated against Staphylococcus aureus (methicillin-resistant or methicillin-sensitive strains) and antifungal efficacy was evaluated against the yeast Candida albicans and the filamentous fungi Aspergillus fumigatus. Overall, the porphyrins tested are more effective against S. aureus. The best results were obtained with zinc diacid porphyrins 4 and 5 after only 3 min of ultra-high irradiation (500 mW/cm, 405 nm), demonstrating that acid-functionalized porphyrins are promising as novel antimicrobial drugs for surface disinfection.
Topics: Microbial Sensitivity Tests; Porphyrins; Aspergillus fumigatus; Candida albicans; Antifungal Agents; Anti-Bacterial Agents; Gram-Positive Bacteria; Staphylococcus aureus; Structure-Activity Relationship; Molecular Structure; Dose-Response Relationship, Drug; Fungi
PubMed: 38906069
DOI: 10.1016/j.bmc.2024.117810 -
World Journal of Microbiology &... Jun 2024This manuscript presents a new report on the in vitro antimicrobial photo-inactivation of foodborne microorganisms (Salmonella spp. and Listeria monocytogenes) using...
In vitro antimicrobial, antibiofilm photodynamic activity, and molecular dynamic simulations of tetra-cationic porphyrinmembrane interactions against foodborne microorganisms.
This manuscript presents a new report on the in vitro antimicrobial photo-inactivation of foodborne microorganisms (Salmonella spp. and Listeria monocytogenes) using tetra-cationic porphyrins. Isomeric tetra-cationic porphyrins (3MeTPyP, 4MeTPyP, 3PtTPyP, and 4PtTPyP) were tested, and antimicrobial activity assays were performed at specific photosensitizer concentrations under dark and white-light LED irradiation conditions. Among the tested bacterial strains, 4MeTPyP exhibited the highest efficiency, inhibiting bacterial growth within just 60 min at low concentrations (17.5 μM). The minimal inhibitory concentration of 4MeTPyP increased when reactive oxygen species scavengers were present, indicating the significant involvement of singlet oxygen species in the photooxidation mechanism. Furthermore, the checkerboard assay testing the association of 4MeTPyP showed an indifferent effect. Atomic force microscopy analyses and dynamic simulations were conducted to enhance our understanding of the interaction between this porphyrin and the strain's membrane.
Topics: Porphyrins; Photosensitizing Agents; Molecular Dynamics Simulation; Biofilms; Microbial Sensitivity Tests; Listeria monocytogenes; Food Microbiology; Anti-Bacterial Agents; Microscopy, Atomic Force; Reactive Oxygen Species; Light; Singlet Oxygen
PubMed: 38904740
DOI: 10.1007/s11274-024-04054-3 -
MSphere Jun 2024Epitopes from the cell surface proteins Fba and Met6 are putative vaccine targets for invasive candidiasis. Here, we describe a vaccine approach in which short...
UNLABELLED
Epitopes from the cell surface proteins Fba and Met6 are putative vaccine targets for invasive candidiasis. Here, we describe a vaccine approach in which short peptides derived from Fba and Met6 are used in spontaneous nanoliposome antigen particle (SNAP) format. SNAP was enabled by the interaction of cobalt porphyrin phospholipid in liposomes with three histidine residues on the N-terminus of synthetic short peptide immunogens from Fba (F-SNAP), Met6 (M-SNAP), or bivalent Fba and Met6 (FM-SNAP). Liposomes were adjuvanted with synthetic monophosphoryl lipid and QS-21. In mice, immunization with F-SNAP, M-SNAP, or FM-SNAP induced antigen-specific IgG responses and mixed Th1/Th2 immunity. The duplex FM-SNAP vaccine elicited stronger antibody responses against each peptide, even at order-of-magnitude lower peptide dosing than a comparable adjuvanted, conjugate vaccine. Enzyme-linked immunosorbent spot analysis revealed the induction of antigen-specific, cytokine-producing T cells. Compared to F-SNAP or M-SNAP, higher production of TNFα, IL-2, and IFNγ was observed with re-stimulation of splenocytes from bivalent FM-SNAP-immunized mice. When vaccinated BALB/c mice were challenged with , analysis of the fungal burden in the kidneys showed that SNAP vaccination protected from disseminated candidiasis. In a lethal fungal exposure model in A/J mice, F-SNAP, M-SNAP, and FM-SNAP vaccination protected mice from candidiasis challenge. Together, these results show that further investigation into the SNAP adjuvant platform is warranted using Fba and Met6 epitopes for a pan- peptide vaccine that provides multifaceted protective immune responses.
IMPORTANCE
This study introduces a promising vaccine strategy against invasive candidiasis, a severe fungal infection, by targeting specific peptides on the surface of . Using a novel approach called spontaneous nanoliposome antigen particle (SNAP), we combined peptides from two key proteins, Fba and Met6, into a vaccine. This vaccine induced robust immune responses in mice, including the production of protective antibodies and the activation of immune cells. Importantly, mice vaccinated with SNAP were shielded from disseminated candidiasis in experiments. These findings highlight a potential avenue for developing a broad-spectrum vaccine against infections, which could significantly improve outcomes for patients at risk of these often deadly fungal diseases.
PubMed: 38904363
DOI: 10.1128/msphere.00189-24 -
Chemical Communications (Cambridge,... Jun 2024Using microflow space, a catalytic effect was achieved for supramolecular polymerization. With increasing reactivity at the polymer end, the selective connection of...
Using microflow space, a catalytic effect was achieved for supramolecular polymerization. With increasing reactivity at the polymer end, the selective connection of active monomers formed new block domains, avoiding fast homo-assembly. Binding of less-reactive monomers at the polymer end overcame steric bulkiness, affording a stable supramolecular diblock copolymer (SdiBCP).
PubMed: 38904123
DOI: 10.1039/d4cc02003k