Reactive molecular dynamics simulation on degradation of aflatoxin B1 by cold atmospheric plasmas

Investigation of Dielectric Barrier Discharge Plasma for the Degradation of Erythromycin Solution

Antibiotic contamination constitutes a serious environmental and public health risk. In order to fill the gap in the study of plasma degradation of erythromycin (ERY), this paper systematically investigated the mechanism of ERY degradation by dielectric barrier discharge (DBD) plasma. The underlying reaction mechanisms were investigated by experiments and molecular dynamics simulations. Plasma emission spectra revealed active hydroxyl radicals (·OH) and argon (Ar) spectral lines. The degradation efficiency of plasma treatment for ERY was found to be strongly influenced by treatment parameters, including applied voltage, treatment duration, and gas flow rate. In particular, a maximum degradation of 90% was achieved for a 250 mg/L ERY solution under conditions of 18 kV voltage, 850 sccm gas flow rate, and 60 min of treatment. The presence of ·OH and hydrogen peroxide (H2O2) in the reaction and their important role in the degradation were proved experimentally. Fracture of the ERY lactone ring induced by hydrogen abstraction reactions with reactive oxygen species (ROS) was observed by molecular dynamics simulations. In the in vitro antimicrobial assays targeting Staphylococcus aureus, the treated solutions demonstrated low toxicity, underscoring the practical applicability of dielectric barrier discharge (DBD) plasma technology in addressing antibiotic contamination in aquatic environments.

Reactive molecular dynamics simulations investigating ROS-mediated HIV damage from outer gp120 protein to internal capsid protein

Molecular dynamics (MD) with the ReaxFF force field is used to study the structural damage to HIV capsid protein and gp120 protein mediated by reactive oxygen species (ROS). Our results show that with an increase in ROS concentration, the structures of the HIV capsid protein and gp120 protein are more severely damaged, including dehydrogenation, increase in oxygen-containing groups, helix shortening or destruction, and peptide bond breaking. In particular, we noticed that extraction of H atoms from N atoms by ROS was significantly higher than that from C atoms. There was no significant difference in the effect of ROS on dehydrogenation and shortening or breaking of the helices. In contrast, the impact of O on the increase in oxygen-containing groups and the fracture of peptide bonds in the gp120 protein is more significant than that of O3, and the effect of O3 is greater than that of ˙OH. In addition, the degree of structural damage of the gp120 protein was greater than that of the capsid protein. These detailed findings deepen our understanding of the role of ROS in regulating the structure and function of the HIV capsid protein and gp120 protein and provide valuable insights for plasma therapy for acquired immune deficiency syndrome (AIDS).

Interaction Mechanisms of Cold Atmospheric Plasmas with HIV Capsid Protein by Reactive Molecular Dynamics Simulation

In recent years, plasma medicine has developed rapidly as a new interdisciplinary discipline. However, the key mechanisms of interactions between cold atmospheric plasma (CAP) and biological tissue are still in the exploration stage. In this study, by introducing the reactive molecular dynamics (MD) simulation, the capsid protein (CA) molecule of HIV was selected as the model to investigate the reaction process upon impact by reactive oxygen species (ROS) from CAP and protein molecules at the atomic level. The simulation results show that ground-state oxygen atoms can abstract hydrogen atoms from protein chains and break hydrogen bonds, leading to the destruction of the disulfide bonds, C-C bonds, and C-N bonds. Furthermore, the generation of alcohol-based groups resulting from the impact of ROS can alter the hydrophobicity of molecules and induce damage to the primary, secondary, and tertiary structures of proteins. The dosage effects on the reaction processes and products induced by CAP are also explored with varying numbers of ROS in the simulation box, and the influences on the broken C-H, N-H, and C-N bonds are discussed. In this study, the computational data suggest that severe damage can be caused to CA upon the impact of ROS by revealing the reaction processes and products.

Recalling the reported toxicity assessment of deoxynivalenol, mitigating strategies and its toxicity mechanisms: Comprehensive review

Mycotoxins frequently contaminate a variety of food items, posing significant concerns for both food safety and public health. The adverse consequences linked to poisoning from these substances encompass symptoms such as vomiting, loss of appetite, diarrhea, the potential for cancer development, impairments to the immune system, disruptions in neuroendocrine function, genetic damage, and, in severe cases, fatality. The deoxynivalenol (DON) raises significant concerns for both food safety and human health, particularly due to its potential harm to vital organs in the body. It is one of the most prevalent fungal contaminants found in edible items used by humans and animals globally. The presence of harmful mycotoxins, including DON, in food has caused widespread worry. Altered versions of DON have arisen as possible risks to the environment and well-being, as they exhibit a greater propensity to revert back to the original mycotoxins. This can result in the buildup of mycotoxins in both animals and humans, underscoring the pressing requirement for additional investigation into the adverse consequences of these modified mycotoxins. Furthermore, due to the lack of sufficient safety data, accurately evaluating the risk posed by modified mycotoxins remains challenging. Our review study delves into conjugated forms of DON, exploring its structure, toxicity, control strategies, and a novel animal model for assessing its toxicity. Various toxicities, such as acute, sub-acute, chronic, and cellular, are proposed as potential mechanisms contributing to the toxicity of conjugated forms of DON. Additionally, the study offers an overview of DON's toxicity mechanisms and discusses its widespread presence worldwide. A thorough exploration of the health risk evaluation associated with conjugated form of DON is also provided in this discussion.

Computational Studies of Aflatoxin B1 (AFB1): A Review

Aflatoxin B₁ (AFB₁) exhibits the most potent mutagenic and carcinogenic activity among aflatoxins. For this reason, AFB₁ is recognized as a human group 1 carcinogen by the International Agency of Research on Cancer. Consequently, it is essential to determine its properties and behavior in different chemical systems. The chemical properties of AFB₁ can be explored using computational chemistry, which has been employed complementarily to experimental investigations. The present review includes in silico studies (semiempirical, Hartree-Fock, DFT, molecular docking, and molecular dynamics) conducted from the first computational study in 1974 to the present (2022). This work was performed, considering the following groups: (a) molecular properties of AFB₁ (structural, energy, solvent effects, ground and the excited state, atomic charges, among others); (b) theoretical investigations of AFB₁ (degradation, quantification, reactivity, among others); (c) molecular interactions with inorganic compounds (Ag⁺, Zn²⁺, and Mg²⁺); (d) molecular interactions with environmentally compounds (clays); and (e) molecular interactions with biological compounds (DNA, enzymes, cyclodextrins, glucans, among others). Accordingly, in this work, we provide to the stakeholder the knowledge of toxicity of types of AFB₁-derivatives, the structure-activity relationships manifested by the bonds between AFB₁ and DNA or proteins, and the types of strategies that have been employed to quantify, detect, and eliminate the AFB₁ molecule.

Advanced mycotoxin control and decontamination techniques in view of an increased aflatoxin risk in Europe due to climate change

Aflatoxins are toxic secondary metabolites produced by Aspergillus spp. found in staple food and feed commodities worldwide. Aflatoxins are carcinogenic, teratogenic, and mutagenic, and pose a serious threat to the health of both humans and animals. The global economy and trade are significantly affected as well. Various models and datasets related to aflatoxins in maize have been developed and used but have not yet been linked. The prevention of crop loss due to aflatoxin contamination is complex and challenging. Hence, the set-up of advanced decontamination is crucial to cope with the challenge of climate change, growing population, unstable political scenarios, and food security problems also in European countries. After harvest, decontamination methods can be applied during transport, storage, or processing, but their application for aflatoxin reduction is still limited. Therefore, this review aims to investigate the effects of environmental factors on aflatoxin production because of climate change and to critically discuss the present-day and novel decontamination techniques to unravel gaps and limitations to propose them as a tool to tackle an increased aflatoxin risk in Europe.