Peroxidase Reaction Research Articles

Hemoglobin peroxidase reaction of hemoglobin efficiently catalyzes oxidation of benzo[a]pyrene

Its high molecular weight endows benzo[a]pyrene (BaP) with strong adsorption to soil, causing serious soil contamination. Our previous study has reported that hemoglobin (Hb) is able to oxidize organic pollutants in the presence of H2O2. This present study showed that Hb catalytic mechanism for BaP oxidation was similar to that of lignin peroxidase. 2-Methyl-3-vinylmaleimide was confirmed as a major degradation intermediate of BaP by Hb catalysis. In addition, BaP was shown to be degraded by heme (Hm)-catalyzed reaction, suggesting that Hm of Hb is the essential catalytic center. Rate constants (k) for BaP oxidation by Hm-catalyzed reaction were 0.4954 h−1. The major degradation intermediate by Hm-catalyzed reaction is 3,3′,5,5′-tetramethylbiphenyl. While values of Km and Vmax of Hb and Hm are very similar, kcat values was 100 times higher with Hb than with Hm. But kcat value for Hb was much lower than that for lignin peroxidase H2. All the results above suggested that Hb-catalyzed reactions efficiently degrade BaP in aqueous condition. Thus, we suggest that Hb for oxygen carrier in blood could be employed as a biocatalyst (i.e., hemoglobin peroxidase) for BaP degradation in the environment, due to the high availability of Hb.

Testis-specific peroxiredoxin 4 variant is not absolutely required for spermatogenesis and fertility in mice

PRDX4, a member of peroxiredoxin family, is largely concentrated in the endoplasmic reticulum (ER) and plays a pivotal role in the redox relay during oxidative protein folding as well as in peroxidase reactions. A testis-specific PRDX4 variant transcript (PRDX4t) lacks the conventional exon 1, which encodes the signal peptide that is required for entry into the ER lumen, but instead carries alternative exon 1, which is transcribed from the upstream promoter in a testis-specific manner and results in the PRDX4t protein being localized in the cytosol. However, the potential roles of PRDX4t in male genital action remain unknown. Using a CRISPR/Cas9 system, we first disrupted the testis-specific promoter/exon 1 and generated mice that were specifically deficient in PRDX4t. The resulting PRDX4t knockout (KO) mice underwent normal spermatogenesis and showed no overt abnormalities in the testis. Mating PRDX4t KO male mice with wild-type (WT) female mice produced normal numbers of offspring, indicating that a PRDX4t deficiency alone had no effect on fertility in the male mice. We then generated mice lacking both PRDX4 and PRDX4t by disrupting exon 2, which is communal to these variants. The resulting double knockout (DKO) mice were again fertile, and mature sperm isolated from the epididymis of DKO mice exhibited a normal fertilizing ability in vitro. In the meantime, the protein levels of glutathione peroxidase 4 (GPX4), which plays an essential role in the disulfide bond formation during spermatogenesis, were significantly increased in the testis and caput epididymis of the DKO mice compared with the WT mice. Based on these results, we conclude that the disruption of the function of PRDX4t in the spermatogenic process appears to be compensated by other factors including GPX4.

How Does Replacement of the Axial Histidine Ligand in Cytochrome c Peroxidase by Nδ-Methyl Histidine Affect Its Properties and Functions? A Computational Study.

Heme peroxidases have important functions in nature related to the detoxification of H2O2. They generally undergo a catalytic cycle where, in the first stage, the iron(III)–heme–H2O2 complex is converted into an iron(IV)–oxo–heme cation radical species called Compound I. Cytochrome c peroxidase Compound I has a unique electronic configuration among heme enzymes where a metal-based biradical is coupled to a protein radical on a nearby Trp residue. Recent work using the engineered Nδ-methyl histidine-ligated cytochrome c peroxidase highlighted changes in spectroscopic and catalytic properties upon axial ligand substitution. To understand the axial ligand effect on structure and reactivity of peroxidases and their axially Nδ-methyl histidine engineered forms, we did a computational study. We created active site cluster models of various sizes as mimics of horseradish peroxidase and cytochrome c peroxidase Compound I. Subsequently, we performed density functional theory studies on the structure and reactivity of these complexes with a model substrate (styrene). Thus, the work shows that the Nδ-methyl histidine group has little effect on the electronic configuration and structure of Compound I and little changes in bond lengths and the same orbital occupation is obtained. However, the Nδ-methyl histidine modification impacts electron transfer processes due to a change in the reduction potential and thereby influences reactivity patterns for oxygen atom transfer. As such, the substitution of the axial histidine by Nδ-methyl histidine in peroxidases slows down oxygen atom transfer to substrates and makes Compound I a weaker oxidant. These studies are in line with experimental work on Nδ-methyl histidine-ligated cytochrome c peroxidases and highlight how the hydrogen bonding network in the second coordination sphere has a major impact on the function and properties of the enzyme.

New Aspects of Cytochrome c: 3D Domain Swapping, Membrane Interaction, Peroxidase Activity, and Met80 Sulfoxide Modification

Abstract Cytochrome (cyt) c is a multifunctional water-soluble heme protein. It transfers electrons from the cyt bc1 complex (Complex III) to cyt c oxidase (Complex IV) in the respiratory chain of mitochondria, and can trigger apoptosis as well. Although cyt c has been studied for more than a century, its new aspects are still being elucidated. For example, we found that cyt c molecules can form oligomers and polymers by 3D domain swapping (3D-DS), where the C-terminal α-helix is exchanged between molecules. 3D-DS is observed in other c-type cyts—although the swapping regions may differ—indicating that 3D-DS is a common feature for c-type cyts. 3D-DS of c-type cyt can occur during protein folding and expression in cells. The electron transfer ability of cyt c decreases by 3D-DS, due to the dissociation of Met80 from the heme iron, whereas the peroxidase activity increases. The cyt c electron transfer partners, Complex III and Complex IV, are embedded in the inner mitochondria membrane, whereas positively charged cyt c interacts with negatively charged cardiolipin (CL) molecules at the inner mitochondrial membrane. We have recently elucidated the CL-interaction site of cyt c at atomic level by NMR spectroscopy using CL-containing bicelles. The membrane interaction site of cyt c is relatively wide and similar to the interaction site for Complex III and Complex IV, indicating that cyt c interacts with lipid membranes and partner proteins in a similar way. When cyt c interacts strongly with CL, Met80 dissociates from the heme iron and the peroxidase activity of cyt c increases. We have shown that the proton concentration at the CL-containing membrane is higher than that in the bulk solution, which may enhance the peroxidase activity of cyt c. The Met80-dissociated cyt c has been shown to oxidize CL, increasing the permeability of cyt c through the membrane. We found that when Met80 is dissociated from the heme iron in cyt c, Met80 can be oxidized to methionine sulfoxide by the peroxidase reaction of the heme of cyt c or its reaction with molecular oxygen under reduced conditions. Met80-oxidized cyt c depicts a higher peroxidase activity compared to that of unmodified cyt c; thus Met80 oxidation may enhance lipid oxidation and eventually apoptosis. These new findings not only help in understanding the structure-function relationships of multifunctional cyt c but also show that there are still hidden properties in well-studied proteins.

Cytochrome c modification and oligomerization induced by cardiolipin hydroperoxides in a membrane mimetic model

Cytochrome c (cytc) is a heme protein of 12 kDa that transfers electrons in the mitochondrial respiratory chain. Increased cytc peroxidase activity leads to cardiolipin (CL) oxidation, a hallmark of early apoptosis stage. Here, we aimed to investigate the interaction between cytc with cardiolipin hydroperoxide (CLOOH) in a mimetic mitochondrial membrane. Cytc-CL peroxidase reaction occurred at faster rates with CLOOH than with H2O2. Moreover, liposomes containing CLOOH promoted increased protein aggregation with minor or no release of cytc from the membrane. Dimeric and trimeric cytc species were observed in the first 15 min, followed by increased formation of high-molecular-weight aggregates afterwards. nLC-MS/MS analysis identified several Lys and His residues covalently modified by lipid aldehydes that showed mass increments corresponding to 4-hydroxynonenal (HNE), 4-oxononenal (ONE), hexanoyl, heptenal and octenal addition. Noteworthy, most modifications were observed at Lys and His residues located at A-site (K73, K87, K88), L-site (H26, H33, and K27) membrane binding sites. Further, dityrosine cross-linked peptides were also characterized at residues Y48-Y74, Y48-Y97 and Y74-Y97. Collectively, our findings show that CLOOH causes irreversible protein damage and crosslinking of cytc in the membrane.

Microfluidic-Integrated Multicolor Immunosensor for Visual Detection of HIV-1 p24 Antigen with the Naked Eye

Here, a fully integrated multicolor immunosensor was developed for sensitive and reliable semiquantitative analysis of HIV-1 p24, which integrates the multistep reactions of horseradish peroxidase (HRP)-linked immunoassay and gold nanorod (AuNR)-based multicolor assay into a single microfluidic chip. The HRP-linked immunoassay functions by moving magnetic beads bound to a capture antibody through different aqueous phases containing immunoassay reagents. HRP-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) is used to mediate AuNRs etching for producing various color changes. Multiple etching processes can be activated by simple mixing of the reagents from the reagent storage reservoir. The fully integrated strategy with sample-in answer-out capability is initiated by simple chip manipulation and finally concluded by converting recognition of antigen-antibody into a vivid color variation for direct visualization and semiquantitative analysis. By bare eye observation, our integrated multicolor immunosensor allows sensitive and reliable semiquantitative analysis of HIV-1 p24 within 1 h. The microfluidic chip device demonstrated here simplifies the operation significantly and thus allows broader application of a multicolor immunosensor for point of care (POC) testing in low-resource settings.

SLC46A1 contributes to hepatic iron metabolism by importing heme in hepatocytes

BackgroundIron is finely regulated due to its vital roles in organisms and the peroxidase reactivity if excess. Solute Carrier Family 46 Member 1 (SLC46A1), also named PCFT or HCP1, is the main importer of heme‑iron in the intestine, but has a high abundance in the liver. Since the liver has a central role in iron homeostasis, whether SLC46A1 regulates hepatic iron metabolism is of interest to be identified. MethodsThe recombinant adeno-associated virus vectors were used to hepatic-specifically inhibit SLC46A1 expression to observe its effects on hepatic iron metabolism. Then the abilities of SLC46A1 in importing heme and folate, and consequent alterations of iron content in hepatocytes were determined. Furthermore, effects of iron on SLC46A1 expression were investigated both in vitro and in vivo. ResultsThe hepatocyte-specific inhibition of SLC46A1 decreases iron content in the liver and increases iron content in serum. Expressions of iron-related molecules, transferrin receptor 1, hepcidin and ferroportin, are correspondingly altered. Interestingly, free heme concentration in serum is increased, indicating a decreased import of heme by the liver. In hepatocytes, SLC46A1 is capable of importing hemin, increasing intracellular iron content. The import of hemin by SLC46A1 is unaffected by its other substrate, folate. Instead, hemin treatment decreases SLC46A1 expression, reducing the import of folate. In addition, SLC46A1 itself shows to be iron-responsive both in vivo and in vitro, making it available for regulating iron metabolism. ConclusionThe results elucidate that SLC46A1 regulates iron metabolism in the liver through a folate-independent manner of importing heme. The iron-responsive characters of SLC46A1 give us a new clue to link heme or iron overload with folate deficiency diseases.

Isoquinoline Coumarin Derivatives as Chemiluminescence Activators in Reactions of Lipid Peroxidation

This study deals with participation of isoquinoline derivatives of coumarin in the peroxidase reaction catalyzed by the cytochrome c–cardiolipin complex. We have studied coumarin derivatives called coumarin-314 (C-314), coumarin-334 (C-334) and coumarin-525 (C-525). These substances are considered as specific physical activators of chemiluminescence, which accompanies the lipid peroxidation reaction. In the course of the scientific research, a spectrophotometric study of the effect of methanol on the structure of cytochrome c was performed, the optical properties of these substances were studied in the medium of a phosphate buffer, and a spectrophotometric study was performed with parallel registration of the chemiluminescence of a mixture in which cytochrome c catalyzed by a complex with cardiolipin lipoperoxidase reaction in the presence of isoquinolysin derivatives of coumarin. The conclusions of this work contain identification of the reversibility of the action of methanol on the structure of cytochrome c, which proves the possibility of using this alcohol in the study of this protein, the positions of absorption maxima and corresponding values of molar absorption coefficients in the medium of 20 mM phosphate buffer (pH = 7.4) for C-314 (λmax = 447.5 nm; e = 32360.4 L/(mol cm)), C-334 (λmax = 460 nm; e = 44 012 L/(mol cm)), and C-525 (λmax = 460 nm; e = 32 703.56 L/(mol cm)). We also demonstrated that the said substances are substrates of cytochrome c/cardiolipin complex-catalyzed peroxidase reaction. Mass flow of these substances during an average statistical experiment in measurement of chemiluminescence (322 s) for C-314, C-334 and C-525 amounted to 31.89, 37.61 and 25.94%, respectively.

Increased expression of PD-1 and PD-L1 in oral lesions progressing to oral squamous cell carcinoma: a pilot study

Oral cancer is a devastating disease and is commonly preceded by a range of oral premalignant disorders. We investigated the expression of PD-1 and PD-L1 in oral epithelial dysplasia (OED) that progressed to oral squamous cell carcinoma (OSCC) compared to non-progressing dysplasia. 49 oral biopsies were analyzed, including 19 progressing cases, 20 cases did not progress, and 10 OSCC. Samples were stained with monoclonal antibodies for PD-1 and PD-L1, followed by conventional peroxidase reaction immunohistochemistry (IHC) imaged under light microscopy or fluorescent immunohistochemistry (FIHC) imaged using a confocal microscope. Images were analyzed using a novel semi-automated analysis protocol. PD-1/PD-L1 expression was assessed at the epithelium/tumor cells (TC) and at inflammatory cells in lamina propria. Our results show a significant increase in PD-L1 expression in progressing compared to non-progressing dysplasia. Using FIHC, we showed increased PD-L1 expression, increased nuclear density in progressing dysplasia and a better interobserver agreement compared with IHC. We developed a new FIHC-based quantitative method to study PD-1/PD-L1 expression in FFPE samples and showed that PD-L1 is highly expressed in premalignant lesions progressing to cancer. Our results suggest that immunomodulation via PD-L1/PD-1 pathway occurs prior to malignant transformation.

The CryoAPEX Method for Electron Microscopy Analysis of Membrane Protein Localization Within Ultrastructurally-Preserved Cells.

Key cellular events like signal transduction and membrane trafficking rely on proper protein location within cellular compartments. Understanding precise subcellular localization of proteins is thus important for answering many biological questions. The quest for a robust label to identify protein localization combined with adequate cellular preservation and staining has been historically challenging. Recent advances in electron microscopy (EM) imaging have led to the development of many methods and strategies to increase cellular preservation and label target proteins. A relatively new peroxidase-based genetic tag, APEX2, is a promising leader in cloneable EM-active tags. Sample preparation for transmission electron microscopy (TEM) has also advanced in recent years with the advent of cryofixation by high pressure freezing (HPF) and low-temperature dehydration and staining via freeze substitution (FS). HPF and FS provide excellent preservation of cellular ultrastructure for TEM imaging, second only to direct cryo-imaging of vitreous samples. Here we present a protocol for the cryoAPEX method, which combines the use of the APEX2 tag with HPF and FS. In this protocol, a protein of interest is tagged with APEX2, followed by chemical fixation and the peroxidase reaction. In place of traditional staining and alcohol dehydration at room temperature, the sample is cryofixed and undergoes dehydration and staining at low temperature via FS. Using cryoAPEX, not only can a protein of interest be identified within subcellular compartments, but also additional information can be resolved with respect to its topology within a structurally preserved membrane. We show that this method can provide high enough resolution to decipher protein distribution patterns within an organelle lumen, and to distinguish the compartmentalization of a protein within one organelle in close proximity to other unlabeled organelles. Further, cryoAPEX is procedurally straightforward and amenable to cells grown in tissue culture. It is no more technically challenging than typical cryofixation and freeze substitution methods. CryoAPEX is widely applicable for TEM analysis of any membrane protein that can be genetically tagged.

A new thin-layer chromatography–direct bioautography assay for the qualitative and quantitative determination of peroxidase inhibitors in plant extracts

Thin-layer chromatography (TLC) hyphenated to bioassays is a modern tool used for discovery of drugs with diverse biological activities from plant extracts which justifies the continuous need for developing such methods. A new TLC–bioautography assay for detecting peroxidase enzyme inhibitors was developed and validated in this study. Peroxidases are related to pathogenesis of many diseases such as neurodegenerative disorders and rheumatoid arthritis and are considered as inflammatory markers. The developed TLC–bioautography method was based on reaction of peroxidase with hydrogen peroxide and the subsequent formation of blue color by the reaction between the released oxygen and benzidine. Compounds with peroxidase inhibition activity are observed as yellowish spots against a blue background. The developed method was validated according to the ICH guidelines. Quantitative estimation of peroxidase inhibitors was achieved by applying image analyses techniques, showing good linearity (R2 = 0.998), accuracy (% recovery 96.6–99.7%), intra-day precisions (RSD% = 0.95–2.35) and inter-day precision (RSD% = 1.80–3.20) as well as low LOD (0.28 μg/spot) and LOQ (0.85 μg/spot). The developed method was applied to different Juniperus species fractions as a demonstrative illustration. Overall, the method proved to be efficient, simple and rapid for identification of peroxidase inhibitors in complex matrices and can be applied in high-throughput screening of plant extracts.

Enzymatic epoxidation of cyclohexene by peroxidase immobilization on a textile and an adapted reactor design

A textile-based reaction system for new peroxidase reactions in non-native media was implemented. The epoxidation of cyclohexene by the commercial peroxidase MaxiBright® was realized with the textile-immobilized enzyme in an adapted liquid-liquid two-phase reactor. A commercially available polyester felt was used as low-price carrier and functionalized with polyvinyl amine. The covalent immobilization with glutardialdehyde lead to an enzyme loading of 0.10 genzyme/gtextile. The textile-based peroxidase shows a high activity retention in the presence of organic media. This catalyst is shown to enable the epoxidation of cyclohexene in various solvents as well as under neat conditions. A model reactor was produced by 3D printing which places the textile catalyst at the interphase between the liquid reaction phase and the product extracting solvent.

Transdermal colorimetric patch for hyperglycemia sensing in diabetic mice

The integration of sampling and instant metabolite readout can fundamentally elevate patient compliance. To circumvent the need for complex in-lab apparatus, here, an all-in-one sampling and display transdermal colorimetric microneedle patch was developed for sensing hyperglycemia in mice. The coloration of 3,3′,5,5′-tetramethylbenzidine (TMB) is triggered by the cascade enzymatic reactions of glucose oxidase (GOx) and horseradish peroxidase (HRP) at abnormally high glucose levels. The HRP in the upper layer is biomineralized with calcium phosphate (CaP) shell to add a pH responsive feature for increased sensitivity as well as protection from nonspecific reactions. This colorimetric sensor achieved minimally invasive extraction of the interstitial fluid from mice and converted glucose level to a visible color change promptly. Quantitative red green and blue (RGB) information could be obtained through a scanned image of the microneedle. This costless, portable colorimetric sensor could potentially detect daily glucose levels without blood drawing procedures.

Effect of titanium or zirconia implant abutments on epithelial attachments after ultrasonic cleaning.

Zirconia is widely employed as a material during dental implant work because of its superior esthetics. This study sought to evaluate the impact of titanium or zirconia implant abutments on epithelial attachments after ultrasonic cleaning. These implants were inserted into the extraction socket of rat maxillary first molars. Then, the length of the horseradish peroxidase (HRP) reaction was measured. In addition, titanium and zirconia disks were cleaned using an ultrasonic scaler, surface morphology changes were observed, and the number of epithelial cell attachments to the surface was measured. Ultimately, the surfaces of the titanium disks were easier to damage than those of the zirconia ones. There was no difference in the number of epithelial cell attachments between the two materials with the ultrasonic cleaning. The length of the HRP reaction was shorter on the zirconia implant abutment surface than on the titanium one after mechanical cleaning. In conclusion, zirconia is harder than titanium and a better choice for use in the epithelial tissue attachment. Zirconia is more suitable as a material for implant abutments than titanium.

Bimetallic Fe/Mn metal-organic-frameworks and Au nanoparticles anchored carbon nanotubes as a peroxidase-like detection platform with increased active sites and enhanced electron transfer

A hybrid of metal-organic frameworks (Fe, Mn) and Au nanoparticles anchored carbon nanotubes (Au/MOFs(Fe, Mn)/CNTs) was fabricated by a facile one-step hydrothermal process. The Au/MOFs(Fe, Mn)/CNTs exhibit highly enhanced peroxidase-like activity, because of the increased active sites, the enhanced partial charge density and electron transfer among the Fermi level of MOFs, Au and CNTs, as well as the synergistic action of Fe and Mn. The hybrid nanomaterials with high catalytic velocity (Vmax = 17.65 × 10−7 M s−1) and affinity (Km = 0.33 mM) for substrates of H2O2 display a great detection performance in the range of 0.34–53.05 nM with a limit of detection (LOD) of 0.18 nM (S/N = 3). Based on the cascade reaction of the artificial peroxidase and glucose oxidase (GOx), the glucose was further better detected in a linear range of 0.005–0.3 μM with a LOD of 0.002 μM (S/N = 3). Notably, considering the regulated peroxidase-like activity by sulfadimethoxine (SDM) aptamer, the concentration of SDM ranging from 0.54 to 41.58 μg L−1 was also detected with a LOD of 0.35 μg L−1 (S/N = 3). The as-synthesized hybrid nanozymes hold promising applications as the multifunctional sensing platform in environmental and biologic target detection with the combination of corresponding enzyme or specific aptamer.

Self-Illuminating Photodynamic Therapy with Enhanced Therapeutic Effect by Optimization of the Chemiluminescence Resonance Energy Transfer Step to the Photosensitizer.

The major obstacles to the wider application of photodynamic therapy (PDT) are drawbacks of the current photosensitizers and the tissue penetration limit of the common outer light source. In the present study, the chemiluminescence (CL) from the luminol-H2O2-horseradish peroxidase reaction was explored as a potential inner light source for the intracellular activation of carbon dots (CDs)-based PDT system. To fully use the light and enhance the overall PDT yield, the nanocarrier of CDs, the light of CL, and the PDT agent chlorin e6 (Ce6) were carefully selected and designed to form an efficient and united system. Bright-yellow-emissive CDs (y-CDs) were synthesized through purposeful regulation of the absorption and emission spectra to enhance the overlapping areas in the chemiluminescence resonance energy transfer (CRET) and fluorescence resonance energy transfer (FRET) processes. Our results reflected CL-induced y-CDs-Ce6 system (10 μM) successfully generated reactive oxygen species (ROS, 35.93%), killed ∼90% SMMC-7721 cells in vitro, and significantly delayed tumor growth in vivo. On the basis of immunohistochemical observations of proliferating cell nuclear antigen (PCNA) and platelet/endothelial cell adhesion molecule-1 (PECAM-1 or CD31) results, we concluded that the CL-induced y-CDs-Ce6 system had excellent performance in cancer therapy. The enhanced therapeutic effect was ascribed to two pathways: a direct CRET process and another process of CRET with subsequent y-CD-mediated FRET (CRET-to-FRET).

A new sensitive spectrophotometric method for determination of saliva and blood glucose.

There is an increasing need for accurate and inexpensive glucometers as the world moves toward personalized medicine. Among the existing technologies, photometric based devices are more desired due to the cost-effectiveness, ease-of-use and the potential to be adopted in the smart-phone technology for remote sensing and self-monitoring purposes. However, the accuracy, precision, and reproducibility of the results of these devices are heavily dependent on the details of the chosen glucose measuring method. Considering the delicate problems with the current spectrophotometric methods, a new method was developed for more precise, accurate, and fast measurement of blood glucose via the coupled reactions of glucose oxidase and peroxidase using 4-[(4-Hydroxy-3-methoxyphenyl) azo]-benzenesulfonic acid (GASA) as the substrate. Stability of GASA and its oxidized products along with its direct and fast consumption by peroxidase, made it possible to determine blood glucose concentration in <20s with high reproducibility. The low detection limit of GASA method (0.36mg dL-1) with a linear range from 0.36 to 399.6mg.dL-1 also allowed determination of salivary glucose concentration (SGC). As compared with the blood samples, the SGC results were more dispersed, especially for the diabetic participants, assumingly due to the diverse nature of salivary samples. However, a good correlation coefficient of 0.81 for non-diabetic individuals showed that it is accurate enough to recognize non-diabetic from diabetic condition. Results of this study disclose the potential application of GASA method as a reliable alternative for the current spectrophotometric methods with the ability to be adopted in miniaturized glucometers.

(±)-Licarin A and its semi-synthetic derivatives: In vitro and in silico evaluation of trypanocidal and schistosomicidal activities

This paper reports the synthesis of (±)-licarin A 1, a dihydrobenzofuran neolignan, resultant of an oxidative coupling reaction of isoeugenol and horseradish peroxidase (HRP) enzyme. Following, three semi-synthetic derivatives from this compound were obtained: benzylated (±)-licarin A 2, methylated (±)-licarin A 3 and acetylated (±)-licarin A 4. After structural elucidation and assignment by Nuclear Magnetic Resonance of 1H, 13C and DEPT, all compounds were evaluated in vitro against Trypomastigote forms of Trypanosoma cruzi (T. cruzi), the etiologic agent of Chagas disease, and Schistosoma mansoni (S. mansoni) worms, the etiologic agent of schistosomiasis. Compound (4) was the most active against S. mansoni adult worms, displaying worm viability reduction at 25 µM and mortality of all worms at 100 and 200 µM within 24 h. Compound 1 was the second most active, showing worm viability reduction at 50 µM and mortality of 25% and 100% of worms in 24h at concentrations of 100 and 200 µM, respectively. In addition, theoretical calculations aiming at finding molecular properties that showed the correlation for schistosomicidal and trypanocidal activities of (±)-licarin A and three of its semi-synthetic derivatives were also performed.

Reply to “Comment on ‘Free-Radical Formation by the Peroxidase-Like Catalytic Activity of MFe2O4 (M = Fe, Ni, and Mn) Nanoparticles’”

RETURN TO ISSUEPREVCommentNEXTReply to “Comment on ‘Free-Radical Formation by the Peroxidase-Like Catalytic Activity of MFe2O4 (M = Fe, Ni, and Mn) Nanoparticles’”Ana Carolina Moreno MaldonadoAna Carolina Moreno MaldonadoInstituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza, SpainMore by Ana Carolina Moreno Maldonado, Elin L. WinklerElin L. WinklerInstituto Balseiro, Universidad Nacional de Cuyo—CNEA, 8400 S. C. Bariloche, Río Negro, ArgentinaInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Elin L. Winklerhttp://orcid.org/0000-0002-9575-7879, Mariana RaineriMariana RaineriInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Mariana Raineri, Alfonso Toro CórdovaAlfonso Toro CórdovaInstituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza, SpainMore by Alfonso Toro Córdova, Luis M. RodríguezLuis M. RodríguezInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Luis M. Rodríguez, Horacio E. TroianiHoracio E. TroianiInstituto Balseiro, Universidad Nacional de Cuyo—CNEA, 8400 S. C. Bariloche, Río Negro, ArgentinaGrupo de Caracterización de Materiales y Óxidos No-Estequiométricos, Gerencia de Investigación Aplicada, CNEA, CONICET, Centro Atómico Bariloche, 8400, S. C. Bariloche, ArgentinaMore by Horacio E. Troiani, Mary Luz Mojica PisciottiMary Luz Mojica PisciottiInstituto Balseiro, Universidad Nacional de Cuyo—CNEA, 8400 S. C. Bariloche, Río Negro, ArgentinaMore by Mary Luz Mojica Pisciotti, Marcelo Vasquez MansillaMarcelo Vasquez MansillaInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Marcelo Vasquez Mansilla, Dina TobiaDina TobiaInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Dina Tobia, Marcela S. NadalMarcela S. NadalInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Marcela S. Nadal, Teobaldo E. TorresTeobaldo E. TorresInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Teobaldo E. Torres, Emilio De BiasiEmilio De BiasiInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Emilio De Biasi, Carlos A. RamosCarlos A. RamosInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Carlos A. Ramos, Gerardo F. GoyaGerardo F. GoyaInstituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, 50018 Zaragoza, SpainDepartamento de Física de la Materia Condensada, Facultad de Ciencias, Universidad de Zaragoza, 50009 Zaragoza, SpainMore by Gerardo F. Goyahttp://orcid.org/0000-0003-1558-9279, Roberto D. ZyslerRoberto D. ZyslerInstituto Balseiro, Universidad Nacional de Cuyo—CNEA, 8400 S. C. Bariloche, Río Negro, ArgentinaInstituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, ArgentinaMore by Roberto D. Zysler, and Enio Lima Jr.*Enio Lima, Jr.Instituto de Nanociencia y Nanotecnología, CNEA, CONICET, Centro Atómico Bariloche, 8400 S. C. Bariloche, Argentina*E-mail: [email protected]More by Enio Lima, Jr.http://orcid.org/0000-0002-6028-4274Cite this: J. Phys. Chem. C 2019, 123, 46, 28511–28512Publication Date (Web):October 22, 2019Publication History Received19 October 2019Published online22 October 2019Published inissue 21 November 2019https://doi.org/10.1021/acs.jpcc.9b09804Copyright © 2019 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views575Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (297 KB) Get e-AlertsSUBJECTS:Iron,Peptides and proteins,Nanoparticles,Ions,Free radicals Get e-Alerts

Enhancing liquid-chilled storage and cryopreservation capacities of ram spermatozoa by supplementing the diluent with different additives.

ObjectiveIn the present study, we determined efficiency of incorporating caffeine, melatonin or omega-3 polyunsaturated fatty acid in the diluent on mitigating consequences of (a) liquid chilled- and (b) cryo-storage of ram spermatozoa.MethodsIn the first experiment, ejaculates (n = 30) were collected from 5 adult rams and were pooled, diluted (1:10) with Tris-citric acid (base diluent) and were split into 4 aliquots assigned for: control (untreated), caffeine (0.1 mM), melatonin (0.3 mM) or omega-3 fatty acids (0.3 mM) (T0). The diluted specimens were stored at 4°C for 48 h, during which sperm physical and cytological properties were evaluated along with oxidative stress indices (T24, T48). In the second experiment, 15 ejaculates (3 per male) were pooled, diluted with glycerolized base diluent (4% glycerol, v/v) and were split corresponding to the same previous treatment groups before being processed for cryopreservation. Post-thaw physical and kinematic sperm properties were assessed by a computer-assisted sperm analysis system.ResultsThe results clarified superiority of both melatonin and omega-3 supplementation on maintaining (p<0.05) sperm properties, while reducing (p<0.05) lipid peroxidase reaction and enzymatic activities of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase in preservation medium, compared to caffeine either during liquid-chilled storage or cryopreservation of spermatozoa.ConclusionMelatonin and omega-3 are regarded efficient alternatives to caffeine when processing ram spermatozoa for application of artificial insemination or in vitro fertilization.