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1.
Food Chem ; 370: 131032, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34500294

RESUMO

Both microbiological and chemical food spoilages remain to be the major challenges in the food industry's efforts to combat food waste and loss because of the lack of high efficacy food preservatives. In this study, dual-functional conjugates that simultaneously suppress both lipid oxidation and microorganism growth are fabricated by covalently conjugating natural antioxidant gentisic acid (GA) on native antibacterial lysozyme (Lys). The mixing ratio of Lys and GA determines the particle size, morphology, antioxidant activity, and antimicrobial performance of the ensuing conjugates. With more of GA being grafted, a drastic decrease in the net surface charge with the concomitant occurrence of aggregations are observed in the conjugates. The maximum antioxidant activity and antibacterial performance of the conjugates is achieved when Lys:GA molar ratio is 1:112. The findings could guide the rational design of future functional food ingredients that combine multiple natural bioactive compounds to effectively intervene food waste and loss.


Assuntos
Anti-Infecciosos , Eliminação de Resíduos , Antibacterianos/farmacologia , Antioxidantes , Alimentos , Gentisatos , Muramidase
2.
Talanta ; 236: 122891, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635270

RESUMO

A molecularly imprinted biosensor for lysozyme based on the polymer nanoparticles self-assembled from water-soluble and electroactive poly (γ-glutamic acid) modified with 3-aminothiophene copolymer were prepared. The water-soluble copolymer made imprinting of lysozyme in aqueous solution possible and thus facilitated improvement of the activity of LYS. Subsequent electro-polymerization not only locked the recognition site between copolymer and lysozyme but also created a conductive polymer network, which can enhance the electron transfer rate and increase the conductivity of the film. The prepared molecularly imprinted biosensor exhibited a wide linear range from 1 × 10-10 to 1 × 10-5 mg mL-1, and satisfactory selectivity, stability, repeatability for lysozyme detection.


Assuntos
Técnicas Biossensoriais , Impressão Molecular , Nanopartículas , Muramidase , Polímeros , Água
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120207, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34419829

RESUMO

Lysozyme (Lyz) is an important antibacterial protein that exists widely in nature. In recent years, the application of graphene oxide (GO) in the field of biotechnology electronics, optics, chemistry and energy storage has been extensively studied. However, due to the unique properties of GO, the mechanism of its interaction with biomacromolecule proteins is very complex. To further explore the interaction between GO and proteins we explore the influence of different pH and heat treatment conditions on the interaction between GO and Lyz, the GO (0-20 µg/mL) was added at a fixed Lyz concentration (0.143 mg/mL) under different pHs. The structure and surface charge changes of Lyz were measured by spectroscopic analysis and zeta potential. The results showed that the interaction between GO and Lyz depends on temperature and pH, significant changes have taken place in its tertiary and secondary structures. By analyzing the UV absorption spectrum, it was found that lysozyme and GO formed a stable complex, and the conformation of the enzyme was changed. In acidic pH conditions (i.e., pH < pI), a high density of Lyz were found to adsorb on the GO surface, whereas an increase in pH resulted in a progressive decrease in the density of the adsorbed Lyz. This pH-dependent adsorption is ascribed to the electrostatic interactions between the negatively charged GO surface and the tunable ionization of the Lyz molecules. The secondary structure of Lyz adsorbed on GO was also found to be highly dependent on the pH. In this paper, we investigated the exact mechanism of pH-influenced GO binding to lysozyme, which has important guidance significance for the potential toxicity of GO biology and its applications in biomedical fields such as structure-based drug design.


Assuntos
Grafite , Muramidase , Adsorção , Muramidase/metabolismo , Estrutura Secundária de Proteína
4.
Molecules ; 26(19)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34641515

RESUMO

Intrinsically disordered proteins (IDPs) are proteins that possess large unstructured regions. Their importance is increasingly recognized in biology but their characterization remains a challenging task. We employed field swept Electron Spin Echoes in pulsed EPR to investigate low-temperature stochastic molecular librations in a spin-labeled IDP, casein (the main protein of milk). For comparison, a spin-labeled globular protein, hen egg white lysozyme, is also investigated. For casein these motions were found to start at 100 K while for lysozyme only above 130 K, which was ascribed to a denser and more ordered molecular packing in lysozyme. However, above 120 K, the motions in casein were found to depend on temperature much slower than those in lysozyme. This abrupt change in casein was assigned to an ordering transition in which peptide residues rearrange making the molecular packing more rigid and/or more cohesive. The found features of molecular motions in these two proteins turned out to be very similar to those known for gel-phase lipid bilayers composed of conformationally ordered and conformationally disordered lipids. This analogy with a simpler molecular system may appear helpful for elucidation properties of molecular packing in IDPs.


Assuntos
Caseínas/química , Proteínas Intrinsicamente Desordenadas/química , Óxidos N-Cíclicos/química , Espectroscopia de Ressonância de Spin Eletrônica , Muramidase/química , Conformação Proteica , Marcadores de Spin , Temperatura
5.
Molecules ; 26(19)2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34641630

RESUMO

Ordered mesoporous materials and their modification with multiple functional groups are of wide scientific interest for many applications involving interaction with biological systems and biomolecules (e.g., catalysis, separation, sensor design, nano-science or drug delivery). In particular, the immobilization of enzymes onto solid supports is highly attractive for industry and synthetic chemistry, as it allows the development of stable and cheap biocatalysts. In this context, we developed novel silylated amino acid derivatives (Si-AA-NH2) that have been immobilized onto SBA-15 materials in biocompatible conditions avoiding the use of toxic catalyst, solvents or reagents. The resulting amino acid-functionalized materials (SBA-15@AA) were characterized by XRD, TGA, EA, Zeta potential, nitrogen sorption and FT-IR. Differences of the physical properties (e.g., charges) were observed while the structural ones remained unchanged. The adsorption of the enzyme lysozyme (Lyz) onto the resulting functionalized SBA-15@AA materials was evaluated at different pHs. The presence of different functional groups compared with bare SBA-15 showed better adsorption results, for example, 79.6 nmol of Lyz adsorbed per m2 of SBA-15@Tyr compared with the 44.9 nmol/m2 of the bare SBA-15.


Assuntos
Aminoácidos/química , Muramidase/química , Dióxido de Silício/química , Adsorção , Enzimas Imobilizadas/química , Concentração de Íons de Hidrogênio , Estrutura Molecular , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
6.
Phys Chem Chem Phys ; 23(39): 22384-22394, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34608908

RESUMO

Ethanol is a common protein crystallization agent, precipitant, and denaturant, but also alters the dielectric properties of solutions. While ethanol-induced unfolding is largely ascribed to its hydrophobic parts, its effect on protein phase separation and inter-protein interactions remains poorly understood. Here, the effects of ethanol and NaCl on the phase behavior and interactions of protein solutions are studied in terms of the metastable liquid-liquid phase separation (LLPS) and the second virial coefficient B2 using lysozyme solutions. Determination of the phase diagrams shows that the cloud-point temperatures are reduced and raised by the addition of ethanol and salt, respectively. The observed trends can be explained using the extended law of corresponding states as changes of B2. The results for B2 agree quantitatively with those of static light scattering and small-angle X-ray scattering experiments. Furthermore, B2 values calculated based on inter-protein interactions described by the Derjaguin-Landau-Verwey-Overbeek (DLVO) potential and considering the dielectric solution properties and electrostatic screening due to the ethanol and salt content quantitatively agree with the experimentally observed B2 values.


Assuntos
Etanol/química , Muramidase/química , Proteínas/química , Muramidase/metabolismo , Soluções , Temperatura , Água/química
7.
Int J Mol Sci ; 22(19)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34638887

RESUMO

Three novel platinum(II) complexes bearing N-heterocyclic ligands, i.e., Pt2c, Pt-IV and Pt-VIII, were previously prepared and characterized. They manifested promising in vitro anticancer properties associated with non-conventional modes of action. To gain further mechanistic insight, we have explored here the reactions of these Pt compounds with a few model proteins, i.e., hen egg white lysozyme (HEWL), bovine pancreatic ribonuclease (RNase A), horse heart cytochrome c (Cyt-c) and human serum albumin (HSA), primarily through ESI MS analysis. Characteristic and variegate patterns of reactivity were highlighted in the various cases that appear to depend both on the nature of the Pt complex and of the interacting protein. The protein-bound Pt fragments were identified. In the case of the complex Pt2c, the adducts formed upon reaction with HEWL and RNase A were further characterized by solving the respective crystal structures: this allowed us to determine the exact location of the various Pt binding sites. The implications of the obtained results are discussed in relation to the possible mechanisms of action of these innovative anticancer Pt complexes.


Assuntos
Complexos de Coordenação/química , Citocromos c/química , Muramidase/química , Platina/química , Ribonuclease Pancreático/química , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Sítios de Ligação , Bovinos , Complexos de Coordenação/metabolismo , Cristalografia por Raios X , Citocromos c/metabolismo , Cavalos , Humanos , Ligantes , Modelos Moleculares , Muramidase/metabolismo , Platina/metabolismo , Ligação Proteica , Domínios Proteicos , Ribonuclease Pancreático/metabolismo , Espectrometria de Massas por Ionização por Electrospray/métodos
8.
Nat Commun ; 12(1): 5795, 2021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34608150

RESUMO

Nanopores are single-molecule sensors used in nucleic acid analysis, whereas their applicability towards full protein identification has yet to be demonstrated. Here, we show that an engineered Fragaceatoxin C nanopore is capable of identifying individual proteins by measuring peptide spectra that are produced from hydrolyzed proteins. Using model proteins, we show that the spectra resulting from nanopore experiments and mass spectrometry share similar profiles, hence allowing protein fingerprinting. The intensity of individual peaks provides information on the concentration of individual peptides, indicating that this approach is quantitative. Our work shows the potential of a low-cost, portable nanopore-based analyzer for protein identification.


Assuntos
Nanoporos , Mapeamento de Peptídeos/métodos , Proteínas/química , Calibragem , Venenos de Cnidários/química , Hidrólise , Muramidase/química , Muramidase/metabolismo , Mapeamento de Peptídeos/normas , Peptídeos/análise , Proteínas/metabolismo
9.
Phys Chem Chem Phys ; 23(40): 23158-23172, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34617942

RESUMO

Herein, we compared the ability of linear and cyclic peptides generated in silico to target different protein sites: internal pockets and solvent-exposed sites. We selected human lysozyme (HuL) as a model target protein combined with the computational evolution of linear and cyclic peptides. The sequence evolution of these peptides was based on the PARCE algorithm. The generated peptides were screened based on their aqueous solubility and HuL binding affinity. The latter was evaluated by means of scoring functions and atomistic molecular dynamics (MD) trajectories in water, which allowed prediction of the structural features of the protein-peptide complexes. The computational results demonstrated that cyclic peptides constitute the optimal choice for solvent exposed sites, while both linear and cyclic peptides are capable of targeting the HuL pocket effectively. The most promising binders found in silico were investigated experimentally by surface plasmon resonance (SPR), nuclear magnetic resonance (NMR), and electrospray ionization mass spectrometry (ESI-MS) techniques. All tested peptides displayed dissociation constants in the micromolar range, as assessed by SPR; however, both NMR and ESI-MS suggested multiple binding modes, at least for the pocket binding peptides. A detailed NMR analysis confirmed that both linear and cyclic pocket peptides correctly target the binding site they were designed for.


Assuntos
Ligantes , Simulação de Dinâmica Molecular , Muramidase/química , Peptídeos/química , Algoritmos , Sequência de Aminoácidos , Sítios de Ligação , Muramidase/metabolismo , Ressonância Magnética Nuclear Biomolecular , Peptídeos/metabolismo , Peptídeos Cíclicos/química , Peptídeos Cíclicos/metabolismo , Ligação Proteica , Espectrometria de Massas por Ionização por Electrospray , Ressonância de Plasmônio de Superfície
10.
PLoS One ; 16(10): e0258429, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34648536

RESUMO

Static light scattering is a popular physical chemistry technique that enables calculation of physical attributes such as the radius of gyration and the second virial coefficient for a macromolecule (e.g., a polymer or a protein) in solution. The second virial coefficient is a physical quantity that characterizes the magnitude and sign of pairwise interactions between particles, and hence is related to aggregation propensity, a property of considerable scientific and practical interest. Estimating the second virial coefficient from experimental data is challenging due both to the degree of precision required and the complexity of the error structure involved. In contrast to conventional approaches based on heuristic ordinary least squares estimates, Bayesian inference for the second virial coefficient allows explicit modeling of error processes, incorporation of prior information, and the ability to directly test competing physical models. Here, we introduce a fully Bayesian model for static light scattering experiments on small-particle systems, with joint inference for concentration, index of refraction, oligomer size, and the second virial coefficient. We apply our proposed model to study the aggregation behavior of hen egg-white lysozyme and human γS-crystallin using in-house experimental data. Based on these observations, we also perform a simulation study on the primary drivers of uncertainty in this family of experiments, showing in particular the potential for improved monitoring and control of concentration to aid inference.


Assuntos
Difusão Dinâmica da Luz , Muramidase/química , gama-Cristalinas/química , Animais , Teorema de Bayes , Galinhas , Humanos , Concentração de Íons de Hidrogênio , Modelos Moleculares , Muramidase/metabolismo , Agregados Proteicos , Cloreto de Sódio/química , gama-Cristalinas/metabolismo
11.
Molecules ; 26(19)2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34641399

RESUMO

In this work we present a computational analysis together with experimental studies, focusing on the interaction between a benzothiazole (BTS) and lysozyme. Results obtained from isothermal titration calorimetry, UV-vis, and fluorescence were contrasted and complemented with molecular docking and machine learning techniques. The free energy values obtained both experimentally and theoretically showed excellent similarity. Calorimetry, UV-vis, and 3D/2D-lig-plot analysis revealed that the most relevant interactions between BTS and lysozyme are based on a predominance of aromatic, hydrophobic Van der Waals interactions, mainly aromatic edge-to-face (T-shaped) π-π stacking interactions between the benzene ring belonging to the 2-(methylthio)-benzothiazole moiety of BTS and the aromatic amino acid residue TRP108 of the lysozyme receptor. Next, conventional hydrogen bonding interactions contribute to the stability of the BTS-lysozyme coupling complex. In addition, mechanistic approaches performed using elastic network models revealed that the BTS ligand theoretically induces propagation of allosteric signals, suggesting non-physiological conformational flexing in large blocks of lysozyme affecting α-helices. Likewise, the BTS ligand interacts directly with allosteric residues, inducing perturbations in the conformational dynamics expressed as a moderate conformational softening in the α-helices H1, H2, and their corresponding ß-loop in the lysozyme receptor, in contrast to the unbound state of lysozyme.


Assuntos
Benzotiazóis/química , Benzotiazóis/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Muramidase/química , Muramidase/metabolismo , Animais , Sítios de Ligação , Galinhas , Ligação de Hidrogênio , Ligantes , Simulação de Acoplamento Molecular , Ligação Proteica , Conformação Proteica , Termodinâmica
12.
Nanoscale ; 13(34): 14469-14479, 2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34473176

RESUMO

The development of various degenerative diseases is suggested to be triggered by the uncontrolled organisation and aggregation of proteins into amyloid fibrils. For this reason, there are ongoing efforts to develop novel agents and approaches, including metal nanoparticle-based colloids, that dissolve amyloid structures and prevent pathogenic protein aggregation. In this contribution, the role of gold nanoparticles (AuNPs) in degrading amyloid fibrils of the model protein lysozyme is investigated. The amino acid composition of fibril surfaces before and after the incubation with AuNPs is determined at the single fibril level by exploiting the high spatial resolution and sensitivity provided by tip-enhanced and surface-enhanced Raman spectroscopies. This combined spectroscopic approach allows to reveal the molecular mechanisms driving the interaction between fibrils and AuNPs. Our results provide an important input for the understanding of amyloid fibrils and could have a potential translational impact on the development of strategies for the prevention and treatment of amyloid-related diseases.


Assuntos
Ouro , Nanopartículas Metálicas , Amiloide , Muramidase , Análise Espectral Raman
13.
J Synchrotron Radiat ; 28(Pt 5): 1284-1295, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34475278

RESUMO

Intense micro-focus X-ray beamlines available at synchrotron facilities have achieved high-quality data collection even from the microcrystals of membrane proteins. The automatic data collection system developed at SPring-8, named ZOO, has contributed to many structure determinations of membrane proteins using small-wedge synchrotron crystallography (SWSX) datasets. The `small-wedge' (5-20°) datasets are collected from multiple crystals and then merged to obtain the final structure factors. To our knowledge, no systematic investigation on the dose dependence of data accuracy has so far been reported for SWSX, which is between `serial crystallography' and `rotation crystallography'. Thus, herein, we investigated the optimal dose conditions for experimental phasing with SWSX. Phase determination using anomalous scattering signals was found to be more difficult at higher doses. Furthermore, merging more homogeneous datasets grouped by hierarchical clustering with controlled doses mildly reduced the negative factors in data collection, such as `lack of signal' and `radiation damage'. In turn, as more datasets were merged, more probable phases could be obtained across a wider range of doses. Therefore, our findings show that it is essential to choose a lower dose than 10 MGy for de novo structure determination by SWSX. In particular, data collection using a dose of 5 MGy proved to be optimal in balancing the amount of signal available while reducing the amount of damage as much as possible.


Assuntos
Cristalografia por Raios X/métodos , Proteínas de Membrana/química , Proteínas de Membrana/efeitos da radiação , Muramidase/química , Muramidase/efeitos da radiação , Modelos Moleculares , Doses de Radiação , Lesões por Radiação , Espalhamento de Radiação , Síncrotrons
14.
Biomater Sci ; 9(20): 6927-6939, 2021 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-34528638

RESUMO

Candida urinary tract biofilms are increasingly witnessed in nosocomial infections due to reduced immunity of patients and the hospital ecosystem. The indwelling devices utilized to support patients with urethral diseases that connect the unsterilized external environment with the internal environment of the patient are another significant source of urinary tract biofilm infections. Recently, nanoparticle (NP)-associated therapeutics have gained traction in a number of areas, including fighting antibiotic-resistant bacterial biofilm infection. However, most studies on nanotherapeutic delivery have only been carried out in laboratory settings rather than in clinical trials due to the lack of precise in vitro and in vivo models for testing their efficiency. Here we develop a novel biofilm-infected 3D human urothelial cell culture model to test the efficiency of nanoparticle (NP)-based antifungal therapeutics. The NPs were designed based on shellac cores, loaded with fluconazole and coated with the cationic enzyme lysozyme. Our formulation of 0.2 wt% lysozyme-coated 0.02 wt% fluconazole-loaded 0.2 wt% shellac NPs, sterically stabilised by 0.25 wt% poloxamer 407, showed an enhanced efficiency in removing Candida albicans biofilms formed on 3D layer of urothelial cell clusteroids. The NP formulation exhibited low toxicity to urothelial cells. This study provides a reliable in vitro model for Candida urinary tract biofilm infections, which could potentially replace animal models in the testing of such antifungal nanotechnologies. The reproducibility and availability of a well-defined biofilm-infected 3D urothelial cell culture model give valuable insights into the formation and clearing of fungal biofilms and could accelerate the clinical use of antifungal nanotherapeutics.


Assuntos
Fluconazol , Nanopartículas , Animais , Biofilmes , Candida , Ecossistema , Fluconazol/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Muramidase , Reprodutibilidade dos Testes , Resinas Vegetais
15.
Bioresour Technol ; 341: 125868, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34523578

RESUMO

This study investigated the influence of temperature on the hydrolysis and decomposition of waste activated sludge (WAS) during the enhanced pretreatment system with lysozyme and rhamnolipid (Ly + RL). Results showed that temperature increasing from 15℃ to 55℃ could obviously enhance the release of soluble organic matters and WAS decomposition degree within the Ly + RL pretreatment system. Compared to the sum of sole Ly and sole RL pretreatment, Ly + RL combined pretreatment system at 45℃ presented best synergistic hydrolysis performance. The decomposition degree of bacteria and archaea reached 47.6% and 88.1%, respectively. Meanwhile, increasing temperature could recede the diversity of microbial community in the system. Gammaproteobacteria, with the relative abundance of 90.7%, occupied the absolute dominant position at 45℃. Furthermore, with the rise of temperature, more volatile fatty acids were harvested after anaerobic fermentation.


Assuntos
Muramidase , Esgotos , Ácidos Graxos Voláteis , Fermentação , Glicolipídeos , Hidrólise , Temperatura
16.
Biomacromolecules ; 22(10): 4327-4336, 2021 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-34533934

RESUMO

Antimicrobial resistance in microorganisms will cause millions of deaths and pose a vast burden on health systems; therefore, alternatives to existing small-molecule antibiotics have to be developed. Lysozyme is an antimicrobial enzyme and has broad-spectrum antimicrobial activity in different aggregated forms. Here, we propose a reductive pathway to obtain colloidally stable amyloid-like worm-shaped lysozyme nanoparticles (worms) from hen egg white lysozyme (HEWL) and compare them to amyloid fibrils made in an acid hydrolysis pathway. The aggregation of HEWL into worms follows strongly pH-dependent kinetics and induces a structural transition from α-helices to ß-sheets. Both HEWL worms and amyloid fibrils show broad-spectrum antimicrobial activity against the bacteria Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative), and the fungus Candida albicans. The colloidal stability of the worms allows the determination of minimum inhibitory concentrations, which are lower than that for native HEWL in the case of S. aureus. Overall, amyloid fibrils have the strongest antimicrobial effect, likely due to the increased positive charge compared to native HEWL. The structural and functional characterizations of HEWL worms and amyloids investigated herein are critical for understanding the detailed mechanisms of antimicrobial activity and opens up new avenues for the design of broad-spectrum antimicrobial materials for use in various applications.


Assuntos
Muramidase , Staphylococcus aureus , Amiloide , Antibacterianos/farmacologia , Escherichia coli
17.
J Phys Chem B ; 125(38): 10701-10709, 2021 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-34546051

RESUMO

Using stopped-flow fluorometry, we determined rate constants for the formation of diffusional encounter complexes of tri-N-acetylglucosamine (NAG3) with hen egg-white lysozyme (kaWT) and its double mutant Asp48Asn/Lys116Gln (kaMT). We defined binding anisotropy, κ ≡ (kaWT - kaMT)/(kaWT + kaMT), and determined its ionic strength dependence. Our goal was to check if this ionic strength dependence provides information about the orienting hydrodynamic effects in the ligand-binding process. We also computed ionic strength dependence of the binding anisotropy from Brownian dynamics simulations using simple models of the lysozyme-NAG3 system. The results of our experiments indicate that in the case of lysozyme and NAG3 such hydrodynamic orienting effects are rather negligible. On the other hand, the results of our Brownian dynamics simulations prove that there exist molecular systems for which such orienting effects are substantial. However, the ionic strength dependence of the rate constants for the wild-type and modified systems do not exhibit any qualitative features that would allow us to conclude the presence of hydrodynamic orienting effects from stopped-flow experiments alone. Nevertheless, the results of our simulations suggest the presence of hydrodynamic orienting effects in the receptor-ligand association when the anisotropy of binding depends on the solvent viscosity.


Assuntos
Acetilglucosamina , Muramidase , Animais , Galinhas/metabolismo , Hidrodinâmica , Muramidase/metabolismo , Concentração Osmolar , Ligação Proteica
18.
Ecotoxicology ; 30(10): 1983-1996, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34529204

RESUMO

The safety of aquatic ecosystems has been compromised by numerous anthropogenic activities, especially leachates from non-point source toxicants, leaching into aquatic systems. This study evaluated the toxicity of the water-soluble fractions (WSFs) of burnt tire ash (BTA) on Clarias gariepinus via a battery of integrated biomarkers. Juvenile C. gariepinus were exposed to sublethal (0.56, 1.12, and 2.24 g/L) concentrations of BTA, derived from 11.2 g/L median lethal concentration (96 LC50), at duration intervals of 1, 14, and 28 days, followed by a recovery trial that lasted for 14 days. Serum biochemical parameters, antioxidant enzyme activities of the gill and liver, lysozymes activity and erythron profile were assessed. The findings of the present study revealed that BTA-WSF induced prominent alterations on biochemical parameters, lysozymes activity and antioxidant enzymes activities in the exposed fish. Furthermore, toxicant exposure promoted oxidative stress, cellular damage and genotoxicity (erythrocytic nuclear and cellular abnormalities) in the exposed fish. In general, a post-exposure trial showed partial recovery from the exposure effects of the toxicant, following the evident modifications of serum enzymes and erythron pathopathology in the experimental model. Biomonitoring of BTA, using sentinel aquatic species such as C. gariepinus, provides insights into the ecotoxicological potency of this toxicant.


Assuntos
Peixes-Gato , Poluentes Químicos da Água , Animais , Ecossistema , Muramidase , Estresse Oxidativo , Água , Poluentes Químicos da Água/toxicidade
19.
Phys Chem Chem Phys ; 23(32): 17536-17544, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34369530

RESUMO

Water, being an active participant in most of the biophysical processes, is important to trace how protein solvation changes as its conformation evolves in the presence of solutes or co-solvents. In this study, we investigate how the secondary structures of two diverse proteins - lysozyme and ß-lactoglobulin - change in the aqueous mixtures of two alcohols - ethanol and 2,2,2-trifluoroethanol (TFE) using circular dichroism measurements. We observe that these alcohols change the secondary structures of these proteins and the changes are protein-specific. Subsequently, we measure the collective solvation dynamics of these two proteins both in the absence and in the presence of alcohols by measuring the frequency-dependent absorption coefficient (α(ν)) in the THz (0.1-1.2 THz) frequency domain. The alcohol-water mixtures exhibit a non-ideal behaviour with the highest absorption difference (Δα) obtained at Xalcohol = 0.2. The protein solvation in the presence of the alcohols shows an oscillating behaviour in which Δαprotein changes with Xalcohol. Such an oscillatory behaviour of protein solvation results from a delicate interplay between the protein-water, protein-alcohol and water-alcohol associations. We attempt to correlate the various structural conformations of the proteins with the associated solvation.


Assuntos
Etanol/química , Lactoglobulinas/química , Muramidase/química , Trifluoretanol/química , Água/química , Animais , Bovinos , Galinhas , Conformação Proteica , Estrutura Secundária de Proteína , Solubilidade , Espectroscopia Terahertz
20.
Environ Toxicol Pharmacol ; 87: 103725, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34416396

RESUMO

The objective of this study was to evaluate the toxic effects of Cr6+ on bioaccumulation, digestion, immunity, oxidative stress, apoptosis and inflammation-related genes in Channa asiatica. The fish was exposed to waterborne Cr6+ concentrations (0, 0.5, 1.0 and 2.0 mg/L) for 28 and 56 days. Our results demonstrated that the accumulation of Cr6+ in tissues increased in a concentration-dependent manner, and the content in tissue was liver > gill > gut > muscle. Meanwhile, Cr6+ exposure led to a remarkable suppression of digestion, immunity and antioxidant capacity in C. asiatica. Inversely, MDA and PC content were positively correlated with Cr6+ exposure concentration. Furthermore, the expression of genes went up with the increase of waterborne Cr6+ concentration. Among them, HSP90, NF-κB and TNF-α have a sharp increase. These results elucidate that waterborne Cr6+ exposure may induce bioaccumulation, inhibit digestion and immunity, promote oxidative stress and up-regulate the expression of apoptosis and inflammation-related genes in C. asiatica.


Assuntos
Cromo/toxicidade , Poluentes Químicos da Água/toxicidade , Alanina Transaminase/sangue , Fosfatase Alcalina/sangue , Animais , Apoptose/efeitos dos fármacos , Aspartato Aminotransferases/sangue , Bioacumulação , Citocinas/sangue , Citocinas/genética , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Peixes/genética , Peixes/imunologia , Peixes/metabolismo , Expressão Gênica/efeitos dos fármacos , Brânquias/metabolismo , Imunoglobulina M/sangue , Mucosa Intestinal/metabolismo , L-Lactato Desidrogenase/sangue , Fígado/metabolismo , Muramidase/sangue , Músculos/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estômago/efeitos dos fármacos , Estômago/enzimologia
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