scholarly journals Antioxidative Peptides from Proteolytic Hydrolysates of False Abalone (Volutharpa ampullacea perryi): Characterization, Identification, and Molecular Docking

Marine Drugs ◽  
2019 ◽  
Vol 17 (2) ◽  
pp. 116 ◽  
Author(s):  
Shudong He ◽  
Yi Zhang ◽  
Hanju Sun ◽  
Ming Du ◽  
Jianlei Qiu ◽  
...  
Keyword(s):  
Scavenging Activity ◽  
Covalent Bonds ◽  
Hydrolysis Degree ◽  
Peptide Fraction ◽  
Hydrolysis Temperature ◽  
Antioxidative Peptide ◽  
Trypsin Hydrolysis ◽  
Reactive Oxidants ◽  
Temperature Time

Antioxidative peptides were produced from false abalone (Volutharpa ampullacea perryi) using enzymatic hydrolysis. Trypsin produced the most bioactive hydrolysates with the highest scavenging ABTS+• free radicals compared to pepsin, alcalase, neutrase, and flavourzyme. The response surface methodology studies on trypsin hydrolysis indicated that the hydrolysis temperature, time, and pH were interacted with each other (p < 0.05), and the optimal conditions were hydrolysis at 51.8 °C for 4.1 h, pH 7.7 and the maximum predicted hydrolysis degree was 13.18% and ABTS+• scavenging activity of 79.42%. The optimized hydrolysate was subjected to ultrafiltration fractionation, and the fraction with MW < 3 kDa showed the highest ABTS+• scavenging activity. There were 193 peptide sequences identified from this peptide fraction and 133 of them were successfully docked onto human myeloperoxidase (MPO), an enzyme involved in forming reactive oxidants in vivo. The highest scored peptide, no. 39, consists of DTETGVPT. Its structure and molecular interactions with MPO active site were compared with previously characterized peptide hLF1-11. The interactions between peptide no. 39 and MPO include electrostatic charge, hydrogen bonds, and covalent bonds. The antioxidative peptide produced in this research may exert antioxidant activity in vivo due to its potential inhibition effect on MPO.

Neurotoxicity of Pesticides: The Roadmap for the Cubic Mode of Action

2020 ◽  
Vol 27 (1) ◽  
pp. 54-77 ◽  
Author(s):  
Bogdan Bumbăcilă ◽  
Mihai V. Putz
Keyword(s):  
Biological Activity ◽  
Wiener Index ◽  
Laboratory Animals ◽  
Covalent Bonds ◽  
Organophosphate Compounds ◽  
Sar Studies ◽  
Structure Activity ◽  
Cubic Structure

Pesticides are used today on a planetary-wide scale. The rising need for substances with this biological activity due to an increasing consumption of agricultural and animal products and to the development of urban areas makes the chemical industry to constantly investigate new molecules or to improve the physicochemical characteristics, increase the biological activities and improve the toxicity profiles of the already known ones. Molecular databases are increasingly accessible for in vitro and in vivo bioavailability studies. In this context, structure-activity studies, by their in silico - in cerebro methods, are used to precede in vitro and in vivo studies in plants and experimental animals because they can indicate trends by statistical methods or biological activity models expressed as mathematical equations or graphical correlations, so a direction of study can be developed or another can be abandoned, saving financial resources, time and laboratory animals. Following this line of research the present paper reviews the Structure-Activity Relationship (SAR) studies and proposes a correlation between a topological connectivity index and the biological activity or toxicity made as a result of a study performed on 11 molecules of organophosphate compounds, randomly chosen, with a basic structure including a Phosphorus atom double bounded to an Oxygen atom or to a Sulfur one and having three other simple covalent bonds with two alkoxy (-methoxy or -ethoxy) groups and to another functional group different from the alkoxy groups. The molecules were packed on a cubic structure consisting of three adjacent cubes, respecting a principle of topological efficiency, that of occupying a minimal space in that cubic structure, a method that was called the Clef Method. The central topological index selected for correlation was the Wiener index, since it was possible this way to discuss different adjacencies between the nodes in the graphs corresponding to the organophosphate compounds molecules packed on the cubic structure; accordingly, &quot;three dimensional&quot; variants of these connectivity indices could be considered and further used for studying the qualitative-quantitative relationships for the specific molecule-enzyme interaction complexes, including correlation between the Wiener weights (nodal specific contributions to the total Wiener index of the molecular graph) and the biochemical reactivity of some of the atoms. Finally, when passing from SAR to Q(uantitative)-SAR studies, especially by the present advanced method of the cubic molecule (Clef Method) and its good assessment of the (neuro)toxicity of the studied molecules and of their inhibitory effect on the target enzyme - acetylcholinesterase, it can be seen that a predictability of the toxicity and activity of different analogue compounds can be ensured, facilitating the in vivo experiments or improving the usage of pesticides.

scholarly journals Facile sonochemical-assisted synthesis of orthorhombic phase black phosphorus/rGO hybrids for effective photothermal therapy

Nanophotonics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 3023-3034
Author(s):  
Weiyuan Liang ◽  
Dou Wang ◽  
Xiaohui Ren ◽  
Chenchen Ge ◽  
Hanyue Wang ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Orthorhombic Phase ◽  
Cost Effective ◽  
Black Phosphorus ◽  
Antitumor Effects ◽  
Covalent Bonds ◽  
Preparation Conditions ◽  
Reduced Graphene

AbstractTwo-dimensional black phosphorus (BP) has been demonstrated to be promising in photoelectronic devices, electrode materials, and biomedicine owing to its outstanding properties. However, the application of BP has been hindered by harsh preparation conditions, high costs, and easy degradation in ambient condition. Herein, we report a facile and cost-effective strategy for synthesis of orthorhombic phase BP and a kind of BP-reduced graphene oxide (BP/rGO) hybrids in which BP remains stable for more than 4 weeks ascribed to the formation of phosphorus-carbon covalent bonds between BP and rGO as well as the protection effect of the unique wrinkle morphology of rGO nanosheets. Surface modification BP/rGO hybrids (PEGylated BP/rGO) exhibit excellent photothermal performance with photothermal conversion efficiency as high as 57.79% at 808 nm. The BP/rGO hybrids exhibit enhanced antitumor effects both in vitro and in vivo, showing promising perspectives in biomedicine.

scholarly journals Size-based characterization of adalimumab and TNF-α interactions using flow induced dispersion analysis: assessment of avidity-stabilized multiple bound species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Morten E. Pedersen ◽  
Ragna M. S. Haegebaert ◽  
Jesper Østergaard ◽  
Henrik Jensen
Keyword(s):  
Protein Interactions ◽  
Free Ligand ◽  
Local Environment ◽  
Dispersion Analysis ◽  
Surface Immobilization ◽  
Covalent Bonds ◽  
Essential Information ◽  
Tnf Α

AbstractThe understanding and characterization of protein interactions is crucial for elucidation of complicated biomolecular processes as well as for the development of new biopharmaceutical therapies. Often, protein interactions involve multiple binding, avidity, oligomerization, and are dependent on the local environment. Current analytical methodologies are unable to provide a detailed mechanistic characterization considering all these parameters, since they often rely on surface immobilization, cannot measure under biorelevant conditions, or do not feature a structurally-related readout for indicating formation of multiple bound species. In this work, we report the use of flow induced dispersion analysis (FIDA) for in-solution characterization of complex protein interactions under in vivo like conditions. FIDA is an immobilization-free ligand binding methodology employing Taylor dispersion analysis for measuring the hydrodynamic radius (size) of biomolecular complexes. Here, the FIDA technology is utilized for a size-based characterization of the interaction between TNF-α and adalimumab. We report concentration-dependent complex sizes, binding affinities (Kd), kinetics, and higher order stoichiometries, thus providing essential information on the TNF-α–adalimumab binding mechanism. Furthermore, it is shown that the avidity stabilized complexes involving formation of multiple non-covalent bonds are formed on a longer timescale than the primary complexes formed in a simple 1 to 1 binding event.

Graphene: Insights on Biological, Radiochemical and Ecotoxicological Aspects

2021 ◽  
Vol 17 (1) ◽  
pp. 131-148
Author(s):  
Xing Haixia ◽  
Aline Oliveira da Silva de Barros ◽  
Francisco do Vale Chaves e Mello ◽  
Fan Sozzi-Guo ◽  
Cristina Müller ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Graphene Quantum Dots ◽  
Covalent Bonds ◽  
Cell Internalization ◽  
Functional Density Theory ◽  
Ecotoxicological Evaluation ◽  
Plasmatic Membrane ◽  
Low Toxicity ◽  
The Impact

Graphene, including graphene quantum dots, its oxide and unoxidized forms (pure graphene) have several properties, like fluorescence, electrical conductivity, theoretical surface area, low toxicity, and high biocompatibility. In this study, we evaluated genotoxicity (in silico analysis using the functional density theory-FDT), cytotoxicity (human glioblastoma cell line), in vivo pharmacokinetics, in vivo impact on microcirculation and cell internalization assay. It was also radiolabeled with lutetium 177 (177Lu), a beta emitter radioisotope to explore its therapeutic use as nanodrug. Finally, the impact of its disposal in the environment was analyzed using ecotoxicological evaluation. FDT analysis demonstrated that graphene can construct covalent and non-covalent bonds with different nucleobases, and graphene oxide is responsible for generation of reactive oxygen species (ROS), corroborating its genotoxicity. On the other hand, non-cytotoxic effect on glioblastoma cells could be demonstrated. The pharmacokinetics analysis showed high plasmatic concentration and clearance. Topical application of 0.1 and 1 mg/kg of graphene nanoparticles on the hamster skinfold preparation did not show inflammatory effect. The cell internalization assay showed that 1-hour post contact with cells, graphene can cross the plasmatic membrane and accumulate in the cytoplasm. Radio labeling with 177Lu is possible and its use as therapeutic nanosystem is viable. Finally, the ecotoxicity analysis showed that A. silina exposed to graphene showed pronounced uptake and absorption in the nauplii gut and formation of ROS. The data obtained showed that although being formed exclusively of carbon and carbon-oxygen, graphene and graphene oxide respectively generate somewhat contradictory results and more studies should be performed to certify the safety use of this nanoplatform.

Membrane Glycoproteins of Human and Rabbit Platelets: Studies In Vitro and after Circulation in Vivo

1975 ◽  
Author(s):  
J. N. George ◽  
P. C. Lewis ◽  
D. A. Sears
Keyword(s):  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Age Distribution ◽  
Human Platelets ◽  
Membrane Glycoproteins ◽  
Rabbit Platelets ◽  
Trypsin Hydrolysis ◽  
Initial Recovery

The initial events of hemostasis and thrombosis involve platelet contact interactions and may be mediated by surface glycoproteins. Human and rabbit platelets were labeled with 125I-diazotized diiodosulfanilic acid (I), which reacts covalently with proteins, and proteins were separated by SDS-polyacrylamide gel electrophoresis. Only exposed membrane proteins were labeled because: 1) protein specific activity of membranes was 4-7 times that of whole platelets, 2) different proteins were labeled when I was reacted with isolated membranes, and 3) trypsin-hydrolysis of labeled intact platelets altered the radioactive peaks. Like Phillips (Biochem. 11, 4582, 72) and Nachman et al. (JBC 248, 2928, 73) we found that lactoperoxidase iodinated the 93,000 dalton glycoprotein (GP) of human platelets. In contrast, I labeled both the 93,000 and 118,000 dalton membrane GP of human platelets, and all 3 membrane GP of rabbit platelets.Rabbit platelets labeled simultaneously with I and 51Cr had identical density and therefore age distribution of the 2 labels. After infusion into rabbits, initial recovery of I was 23% of the Cr recovery. After 3 hrs, I disappearance was exponential and more rapid (T/2 = 17 hrs) than the linear Cr disappearance (T/2 = 30 hrs, p < .01). This was due to in vivo removal of I from circulating platelets since 1 did not elute more rapidly from platelets harvested after 3 hrs circulation and incubated in plasma at 37° (T/2 of I elution = 43 hrs, Cr = 33 hrs). Platelets harvested after 14-20 hrs circulation had the same distribution of I on the membrane GP as before circulation. We postulate that this symmetrical label loss indicates uniform loss of membrane GP, suggesting that platelets lose pieces of their plasma membrane during circulation. This could occur during contact interaction in the process of hemostasis.

scholarly journals The Immunosuppressive Activity of Plasmic Degradation Products of Human Fibrinogen

1977 ◽  
Author(s):  
T.S. Edgington ◽  
L.K. Curtiss ◽  
E.F. Plow
Keyword(s):  
Cell Response ◽  
Degradation Products ◽  
Thymidine Uptake ◽  
Immunosuppressive Activity ◽  
Human Fibrinogen ◽  
Peptide Fraction ◽  
Intact Molecule ◽  
Stimulation Of

Plasmic cleavage of human fibrinogen leads to generation of immunosuppressive activity not expressed by the intact molecule, and which is demonstrable in vitro and in vivo. This activity is not associated with the high molecular weight derivatives X, Y, D and E, but is present in the small dialyzable peptide fraction obtained from plasmic digestion. The peptides inhibit in a non-toxic fashion, the stimulation of 3H-thymidine uptake and blastogenesis of lymphocytes by phytohemagglutinin (PHA) and allogeneic cells (MLC) under conditions of both macrophage dependence and macrophage independence. The peptides also suppress the plaque-forming cell response of mice to sheep red blood cells in vivo. Approximately 30 μg peptides/culture leads to a 50% inhibition of the PHA and MLC systems, and approximately 400 μg/mouse produces a 50% suppression of the plaque-forming cell response. Intact fibrinogen chains exhibit negligible activity, but plasmic digests of Aα chain are suppressive. Consistent with derivation from the Aa chain was the demonstration that the activity was generated from limited plasmic digest of fibrinogen which produced fragment X, and this activity was soluble at 80°C for 10 minutes. The release of the active peptide by limited plasmic degradation, and the activity of these peptides at physiologic concentrations suggests that this system may be of importance in vivo in association with local fibrinogenolysis or fibrinolysis at sites of thrombosis. This has been in part substantiated by the experimental initiation of fibrinogenolysis in vivo with streptokinase.

scholarly journals Covalent crosslinking of von Willebrand factor to fibrin

Blood ◽  
1986 ◽  
Vol 68 (1) ◽  
pp. 95-101 ◽  
Author(s):  
M Hada ◽  
M Kaminski ◽  
P Bockenstedt ◽  
J McDonagh
Keyword(s):  
Von Willebrand Factor ◽  
Initial Rate ◽  
Factor Xiiia ◽  
Covalent Bonds ◽  
Covalent Crosslinking ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Plasmin Inhibitor

Abstract Factor XIIIa crosslinks a limited number of substrates via epsilon(gamma-glutamyl)-lysyl bond formation. It crosslinks fibrin to itself, alpha 2-plasmin inhibitor and fibronectin to fibrin, and fibronectin to collagen. Results presented here show that plasma von Willebrand factor (vWF) is a substrate for factor XIIIa and can be crosslinked to fibrin during gel formation. vWF-fibrin crosslinking was studied in purified systems and in plasma with 125I-vWF and 131I- fibrinogen. vWF incorporation into fibrin increased with time or increasing factor XIIIa. After electrophoresis of dissolved clots, distribution of 125I and 131I was measured and showed that vWF was crosslinked to the alpha chain of fibrin and entered the high-mol-wt alpha polymer. vWF-fibrin crosslinking decreased the initial rate of alpha polymer formation. Crosslinking of vWF polymer to itself could not be demonstrated under physiologic conditions but occurred if vWF was reduced first. Factor XIIIa catalyzed incorporation of putrescine into both monomeric and polymeric vWF. Altogether, these studies indicate that factor XIIIa can readily form covalent bonds between glutamine in vWF and lysine in fibrin alpha chains. This reaction occurs readily in vitro when plasma clotting is slow and may occur in vivo under similar conditions.

scholarly journals Detoxifying effects of ultrafiltration fractions of Dendrobium aphyllum peptides on chemical and AAPH-induced oxidative stress

RSC Advances ◽  
2017 ◽  
Vol 7 (77) ◽  
pp. 48913-48924 ◽  
Author(s):  
Huifan Liu ◽  
Juanjuan Ma ◽  
Hui Wu
Keyword(s):  
Oxidative Stress ◽  
Peptide Fraction ◽  
Antioxidative Peptide ◽  
Dendrobium Aphyllum

The antioxidative peptide fraction extracted from Dendrobium aphyllum displayed good detoxifying effects on chemical and AAPH-induced oxidative stress.

scholarly journals Effect of Temperature, pH, Enzyme to Substrate Ratio, Substrate Concentration and Time on the Antioxidative Activity of Hydrolysates from Goat Milk Casein by Alcalase

2016 ◽  
Vol 20 (2) ◽  
pp. 29-38 ◽  
Author(s):  
Guowei Shu ◽  
Bowen Zhang ◽  
Qian Zhang ◽  
Hongchang Wan ◽  
Hong Li
Keyword(s):  
Substrate Concentration ◽  
Superoxide Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Goat Milk ◽  
Scavenging Activity ◽  
Antioxidant Peptides ◽  
Hydrolysis Time ◽  
Hydrolysis Temperature ◽  
Milk Casein

Abstract The effect of hydrolysis temperature (45, 50, 55, 60 and 65°C), pH (7.0, 7.5, 8.0, 8.5 and 9.0), enzyme to substrate (E/S) ratio (1.0, 1.5, 2.0, 2.5 and 3.0%), substrate concentration (2, 3, 4, 5 and 6%) and hydrolysis time (30-240min) on antioxidant peptides hydrolysated from goat’s milk casein by Alcalase was investigated using single factor experiment. In order to obtain high DPPH radical-scavenging activity, metal-chelating activity and superoxide radical scavenging activity, the optimal conditions were hydrolysis time of 150 min, temperature of 50°C, pH 8.0, E/S ratio of 2.0% and substrate concentration of 4.0%. The hydrolysis time, hydrolysis temperature, pH, E/S ratio and substrate concentration had a significant influence on degree of hydrolysis, metal-chelating activity, DPPH and superoxide radical scavenging activity on casein hydrolysate of goat milk by Alcalase, the results were beneficial for further provide theoretical basis for production of antioxidant peptides.

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