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Biosensors & Bioelectronics Sep 2024Electrochemical detection of miRNA biomarkers in complex physiological samples holds great promise for accurate evaluation of tumor burden in the perioperative period,...
Electrochemical detection of miRNA biomarkers in complex physiological samples holds great promise for accurate evaluation of tumor burden in the perioperative period, yet limited by reproducibility and bias issues. Here, nanosensors installed with hybrid probes that responsively release catalytic DNAzymes (G-quadruplexes/hemin) were developed to solve the fidelity challenge in an immobilization-free detection. miRNA targets triggered toehold-mediated strand displacement reactions on the sensor surface and resulted in amplified shedding of DNAzymes. Subsequently, the interference background was removed by FeO core-facilitated magnetic separation. Binding aptamers of the electrochemical reporter (dopamine) were tethered closely to the catalytic units for boosting HO-mediated oxidation through proximity catalysis. The one-to-many conversion by dual amplification from biological-chemical catalysis facilitated sufficient homogeneous sensing signals on electrodes. Thereby, the nanosensor exhibited a low detection limit (2.08 fM), and high reproducibility (relative standard deviation of 1.99%). Most importantly, smaller variations (RSD of 0.51-1.04%) of quantified miRNAs were observed for detection from cell lysates, multiplexed detection from unprocessed serum, and successful discrimination of small upregulations in lysates of tumor tissue samples. The nanosensor showed superior diagnostic performance with an area under curve (AUC) of 0.97 and 94% accuracy in classifying breast cancer patients and healthy donors. These findings demonstrated the synergy of signal amplification and interference removal in achieving high-fidelity miRNA detection for practical clinical applications.
Topics: Humans; Biosensing Techniques; MicroRNAs; Electrochemical Techniques; DNA, Catalytic; Limit of Detection; Catalysis; G-Quadruplexes; Breast Neoplasms; Hydrogen Peroxide; Aptamers, Nucleotide; Female; Hemin; Reproducibility of Results; Biomarkers, Tumor
PubMed: 38820724
DOI: 10.1016/j.bios.2024.116435 -
Journal of Bacteriology Jun 2024Iron acquisition systems are crucial for pathogen growth and survival in iron-limiting host environments. To overcome nutritional immunity, bacterial pathogens evolved...
UNLABELLED
Iron acquisition systems are crucial for pathogen growth and survival in iron-limiting host environments. To overcome nutritional immunity, bacterial pathogens evolved to use diverse mechanisms to acquire iron. Here, we examine a heme acquisition system that utilizes hemophores called hemophilins which are also referred to as HphAs in several Gram-negative bacteria. In this study, we report three new HphA structures from , , and . Structural determination of HphAs revealed an N-terminal clamp-like domain that binds heme and a C-terminal eight-stranded β-barrel domain that shares the same architecture as the Slam-dependent Neisserial surface lipoproteins. The genetic organization of HphAs consists of genes encoding a Slam homolog and a TonB-dependent receptor (TBDR). We investigated the Slam-HphA system in the native organism or the reconstituted system in cells and found that the efficient secretion of HphA depends on Slam. The TBDR also played an important role in heme uptake and conferred specificity for its cognate HphA. Furthermore, bioinformatic analysis of HphA homologs revealed that HphAs are conserved in the alpha, beta, and gammaproteobacteria. Together, these results show that the Slam-dependent HphA-type hemophores are prevalent in Gram-negative bacteria and further expand the role of Slams in transporting soluble proteins.
IMPORTANCE
This paper describes the structure and function of a family of Slam (Type IX secretion System) secreted hemophores that bacteria use to uptake heme (iron) while establishing an infection. Using structure-based bioinformatics analysis to define the diversity and prevalence of this heme acquisition pathway, we discovered that a large portion of gammaproteobacterial harbors this system. As organisms, including , utilize this system to facilitate survival during host invasion, the identification of this heme acquisition system in bacteria species is valuable information and may represent a target for antimicrobials.
Topics: Gram-Negative Bacteria; Heme; Bacterial Proteins; Iron
PubMed: 38814789
DOI: 10.1128/jb.00027-24 -
Journal of the American Chemical Society Jun 2024Artificial syntheses of biologically active molecules have been fruitful in many bioinspired catalysis applications. Specifically, verdoheme and biliverdin, bearing...
Artificial syntheses of biologically active molecules have been fruitful in many bioinspired catalysis applications. Specifically, verdoheme and biliverdin, bearing polypyrrole frameworks, have inspired catalyst designs to address energy and environmental challenges. Despite remarkable progress in benchtop synthesis of verdoheme and biliverdin derivatives, all reported syntheses, starting from metalloporphyrins or inaccessible biliverdin precursors, require multiple steps to achieve the final desired products. Additionally, such synthetic procedures use multiple reactants/redox agents and involve multistep purification/extraction processes that often lower the yield. However, in a single step using atmospheric oxygen, heme oxygenases selectively generate verdoheme or biliverdin from heme. Motivated by such enzymatic pathways, we report a single-step electrosynthesis of verdoheme or biliverdin derivatives from their corresponding meso-aryl-substituted metalloporphyrin precursors. Our electrosynthetic methods have produced a copper-coordinating verdoheme analog in >80% yield at an applied potential of 0.65 V vs ferrocene/ferrocenium in air-exposed acetonitrile solution with a suitable electrolyte. These electrosynthetic routes reached a maximum product yield within 8 h of electrolysis at room temperature. The major products of verdoheme and biliverdin derivatives were isolated, purified, and characterized using electrospray mass spectrometry, absorption spectroscopy, cyclic voltammetry, and nuclear magnetic resonance spectroscopy techniques. Furthermore, X-ray crystallographic data were collected for select cobalt (Co)- and Cu-chelating verdoheme and metal-free biliverdin products. Electrosynthesis routes for the selective modification at the macrocycle ring in a single step are not known yet, and therefore, we believe that this report would advance the scopes of electrosynthesis strategies.
Topics: Biliverdine; Heme; Electrochemical Techniques; Heme Oxygenase (Decyclizing); Porphyrins; Molecular Structure
PubMed: 38814055
DOI: 10.1021/jacs.4c02847 -
ACS Omega May 2024Antibiotics are frequently used to treat, prevent, or control bacterial infections, but in recent years, infections resistant to all known classes of conventional...
Antibiotics are frequently used to treat, prevent, or control bacterial infections, but in recent years, infections resistant to all known classes of conventional antibiotics have significantly grown. The development of novel, nontoxic, and nonincursive antimicrobial methods that work more quickly and efficiently than the present antibiotics is required to combat this growing public health issue. Here, Co(II) and Zn(II) derivatives of tetrakis(1-methylpyridinium-4yl)porphyrin [HTMPyP] as a tetra(ρ-toluenesulfonate) were synthesized and purified to investigate their interactions with DNA (pH 7.40, 25 °C) using UV-vis, fluorescence techniques, and antimicrobial activity. UV-vis results showed that [HTMPyP] had a high hypochromicity (∼64%) and a substantial bathochromic shift (Δλ, 14 nm), while [Co(II)TMPyP] and [Zn(II)TMPyP] showed little hypochromicity (∼37%) and a small bathochromic shift (Δλ, 3-6 nm). Results reveal that [HTMPyP] interacts with DNA via intercalation, while Co(II)- and [Zn(II)TMPyP] interact with DNA via outside self-stacking. Fluorescence results also confirmed the interaction of [HTMPyP] and the metalloporphyrins with DNA. Results of the antimicrobial activity assay revealed that the metalloporphyrins showed inhibitory effects on Gram-positive and Gram-negative bacteria and fungi, but that neither the counterions nor [HTMPyP] exhibited any inhibitory effects. Mechanism of antimicrobial activities of metalloporphyrins are discussed.
PubMed: 38799349
DOI: 10.1021/acsomega.4c01708 -
Chemistry (Weinheim An Der Bergstrasse,... May 2024Cationic Mn(III)-meso-tetraarylporphyrin derivatives, substituted in para position with different size alkyl chains, were investigated to function as antioxidants in...
Cationic Mn(III)-meso-tetraarylporphyrin derivatives, substituted in para position with different size alkyl chains, were investigated to function as antioxidants in free-radical degradation of high-molar-mass hyaluronan by the methods of rotational viscometry and oximetry. The results of rotational viscometry showed that MnTM-4-PyP5+, MnTE-4-PyP5+, MnTPr-4-PyP5+, MnTPen-4-PyP5+ and MnTHep-4-PyP5+ showed high efficiency in decomposing H2O2, and reducing of peroxidized hyaluronan. When using oxygen electrode, MnTE-4-PyP5+, MnTPr-4-PyP5+, MnTPen-4-PyP5+, and MnTHep-4-PyP5+ applied to function as protective antioxidants in hyaluronan degradation, the uptake of dissolved oxygen from the reaction milieu was rapid, followed by continual increase in oxygen concentration up to the end of the measurement. However, when especially MnTE-4-PyP5+, MnTPr-4-PyP5+, and MnTPen-4-PyP5+ were examined as hyaluronan chain-breaking antioxidants, after short-term dissolved oxygen uptake, almost no increase in oxygen concentration was shown.
PubMed: 38797703
DOI: 10.1002/chem.202401028 -
Water Research Jul 2024Nano zero-valent metals (nZVMs) have been extensively utilized for decades in the reductive remediation of groundwater contaminated with chlorinated organic compounds,...
Nano zero-valent metals (nZVMs) have been extensively utilized for decades in the reductive remediation of groundwater contaminated with chlorinated organic compounds, owing to their robust reducing capabilities, simple application, and cost-effectiveness. Nevertheless, there remains a dearth of information regarding the efficient reductive defluorination of linear or branched per- and polyfluoroalkyl substances (PFASs) using nZVMs as reductants, largely due to the absence of appropriate catalysts. In this work, various soluble porphyrin ligands [[meso‑tetra(4-carboxyphenyl)porphyrinato]cobalt(III)]Cl·7HO (CoTCPP), [[meso‑tetra(4-sulfonatophenyl) porphyrinato]cobalt(III)]·9HO (CoTPPS), and [[meso‑tetra(4-N-methylpyridyl) porphyrinato]cobalt(II)](I)·4HO (CoTMpyP) have been explored for defluorination of PFASs in the presence of the nZn as reductant. Among these, the cationic CoTMpyP showed best defluorination efficiencies for br-perfluorooctane sulfonate (PFOS) (94%), br-perfluorooctanoic acid (PFOA) (89%), and 3,7-Perfluorodecanoic acid (PFDA) (60%) after 1 day at 70 °C. The defluorination rate constant of this system (CoTMpyP-nZn) is 88-164 times higher than the VB-nZn system for the investigated br-PFASs. The CoTMpyP-nZn also performed effectively at room temperature (55% for br-PFOS, 55% for br-PFOA and 25% for 3,7-PFDA after 1day), demonstrating the great potential of in-situ application. The effect of various solubilizing substituents, electron transfer flow and corresponding PFASs defluorination pathways in the CoTMpyP-nZn system were investigated by both experiments and density functional theory (DFT) calculations. SYNOPSIS: Due to the unavailability of active catalysts, available information on reductive remediation of PFAS by zero-valent metals (ZVMs) is still inadequate. This study explores the effective defluorination of various branched PFASs using soluble porphyrin-ZVM systems and offers a systematic approach for designing the next generation of catalysts for PFAS remediation.
Topics: Zinc; Porphyrins; Fluorocarbons; Metalloporphyrins; Water Pollutants, Chemical; Oxidation-Reduction
PubMed: 38795548
DOI: 10.1016/j.watres.2024.121803 -
International Journal of Molecular... May 2024Heme biosynthesis is a highly conserved pathway from bacteria to higher animals. Heme, which serves as a prosthetic group for various enzymes involved in multiple...
Heme biosynthesis is a highly conserved pathway from bacteria to higher animals. Heme, which serves as a prosthetic group for various enzymes involved in multiple biochemical processes, is essential in almost all species, making heme homeostasis vital for life. However, studies on the biological functions of heme in filamentous fungi are scarce. In this study, we investigated the role of heme in . A mutant lacking the rate-limiting enzymes in heme synthesis, coproporphyrinogen III oxidase (Cpo) or ferrochelatase (Fc), was constructed using a homologous recombination strategy. The results showed that the absence of these enzymes was lethal to , but the growth defect could be rescued by the addition of hemin, so we carried out further studies with the help of hemin. The results demonstrated that heme was required for the activity of FgCyp51, and its absence increased the sensitivity to tebuconazole and led to the upregulation of in . Additionally, heme plays an indispensable role in the life cycle of , which is essential for vegetative growth, conidiation, external stress response (especially oxidative stress), lipid accumulation, fatty acid β-oxidation, autophagy, and virulence.
Topics: Fusarium; Heme; Fungal Proteins; Stress, Physiological; Oxidative Stress; Triazoles; Gene Expression Regulation, Fungal; Fungicides, Industrial; Ferrochelatase
PubMed: 38791308
DOI: 10.3390/ijms25105268 -
Mikrochimica Acta May 2024A new sandwich-type electrochemical biosensing platform was developed by gold @polyphthalenediamine nanohybrids (AuNP@PoPD) as the sensing platform and phosphorus doped...
A new sandwich-type electrochemical biosensing platform was developed by gold @polyphthalenediamine nanohybrids (AuNP@PoPD) as the sensing platform and phosphorus doped reduced graphene oxide-hemin-palladium nanoparticles (PrGO-Hemin-PdNP) as the signal amplifier for phosphatidylinositol proteoglycan 3 (GPC3). AuNP@PoPD, co-electrodeposited into the screen printed electrode with high conductivity and stability, is dedicated to assembling the primary GPC3 aptamer (GPC3). The second GPC3 immobilized on the high conductivity and large surface area of PrGO-Hemin-PdNP was utilized as an electrochemical signal reporter by hemin oxidation (PrGO-Hemin-PdNP-GPC3). In the range 0.001-10.0 ng/mL, the hemin oxidation current signal of the electrochemical aptasensor increased log-linearly with the concentration of GPC3, the lowest detection limit was 0.13 pg/mL, and the sensitivity was 2.073 μA/μM/cm. The aptasensor exhibited good sensing performance in a human serum sample with the relative error of 4.31-8.07%. The sandwich sensor showed good selectivity and stability for detection GPC3 in human serum samples, providing a new efficient and sensitive method for detecting HCC markers.
Topics: Glypicans; Humans; Electrochemical Techniques; Aptamers, Nucleotide; Hemin; Graphite; Palladium; Gold; Biosensing Techniques; Limit of Detection; Metal Nanoparticles; Electrodes
PubMed: 38787447
DOI: 10.1007/s00604-024-06419-9 -
Biomimetics (Basel, Switzerland) Apr 2024To inhibit the deep conversion of partial oxidation products (POX-products) in C-H bonds' functionalization utilizing O,...
Efficient Inhibition of Deep Conversion of Partial Oxidation Products in C-H Bonds' Functionalization Utilizing O via Relay Catalysis of Dual Metalloporphyrins on Surface of Hybrid Silica Possessing Capacity for Product Exclusion.
To inhibit the deep conversion of partial oxidation products (POX-products) in C-H bonds' functionalization utilizing O, 5-(4-(chloromethyl)phenyl)-10,15,20-tris(perfluorophenyl)porphyrin cobalt(II) and 5-(4-(chloromethyl)phenyl)-10,15,20-tris(perfluorophenyl)porphyrin copper(II) were immobilized on the surface of hybrid silica to conduct relay catalysis on the surface. Fluorocarbons with low polarity and heterogeneous catalysis were devised to decrease the convenient accessibility of polar POX-products to catalytic centers on the lower polar surface. Relay catalysis between Co and Cu was designed to utilize the oxidation intermediates alkyl hydroperoxides to transform more C-H bonds. Systematic characterizations were conducted to investigate the structure of catalytic materials and confirm their successful syntheses. Applied to C-H bond oxidation, not only deep conversion of POX-products was inhibited but also substrate conversion and POX-product selectivity were improved simultaneously. For cyclohexane oxidation, conversion was improved from 3.87% to 5.27% with selectivity from 84.8% to 92.3%, which was mainly attributed to the relay catalysis on the surface excluding products. The effects of the catalytic materials, product exclusion, relay catalysis, kinetic study, substrate scope, and reaction mechanism were also investigated. To our knowledge, a practical and novel strategy was presented to inhibit the deep conversion of POX-products and to achieve efficient and accurate oxidative functionalization of hydrocarbons. Also, a valuable protocol was provided to avoid over-reaction in other chemical transformations requiring high selectivity.
PubMed: 38786482
DOI: 10.3390/biomimetics9050272 -
Analytica Chimica Acta Nov 2023Post-operative pathogenic infections in liver transplantation seriously threaten human health. It is essential to develop novel methods for the highly sensitive and...
Post-operative pathogenic infections in liver transplantation seriously threaten human health. It is essential to develop novel methods for the highly sensitive and rapid detection of Staphylococcus aureus (S. aureus). Interestingly, the combination of the property of bacteria to secrete hydrogen peroxidase, bacterial metabolism-triggered-chemiluminescence (CL)-based bioassays can be as a candidate point-of-care testing (POCT) for the detection of S. aureus against the CL substrate Luminol and hydrogen peroxide without excitation light sources. Here, a CL-based strategy with stable and visualized CL intensity was fabricated according to a hybrid biomimetic enzyme of copper-Hemin metal-organic framework, which enhances the biological enzyme activity while improving the stability and sensitivity of the assay. By further integrating S. aureus-specific capture and one-step separation of the antibody-modified FeO NPs (FeO NPs@Ab), the portable device integrated smartphone enables CL-based POCT for specific detection of S. aureus in the range of 10-10 CFU/mL with a limit of detection as low as 1 CFU/mL. Specifically, S. aureus can be eliminated after detection with high antibacterial efficiency due to the excellent photothermal properties of FeO NPs@Ab. The developed multifunctional platform has the advantages of simplicity of operation and low cost, indicating great potential in clinical applications.
Topics: Staphylococcus aureus; Luminescent Measurements; Point-of-Care Testing; Luminol; Hydrogen Peroxide; Humans; Limit of Detection; Copper; Magnetite Nanoparticles; Metal-Organic Frameworks; Hemin; Luminescence
PubMed: 38783739
DOI: 10.1016/j.aca.2023.341899