Exposure to 50Hz-sinusoidal electromagnetic field induces DNA damage-independent autophagy.

As electromagnetic field (EMF) is commonly encountered within our daily lives, the biological effects of EMF are of great concern. Autophagy is a key process for maintaining cellular homeostasis, and it can also reveal cellular responses to environmental stimuli. In this study, we aim to investigate the biological effects of a 50Hz-sinusoidal electromagnetic field on autophagy and we identified its mechanism of action in Chinese Hamster Lung (CHL) cells. CHL cells were exposed to a 50Hz sinusoidal EMF at 0.4mT for 30min or 24h. In this study, we found that a 0.4mT EMF resulted in: (i) an increase in LC3-II expression and increased autophagosome formation; (ii) no significant difference in the incidence of γH2AX foci between the sham and exposure groups; (iii) reorganized actin filaments and increased pseudopodial extensions without promoting cell migration; and (iv) enhanced cell apoptosis when autophagy was blocked by Bafilomycin A1. These results implied that DNA damage was not directly involved in the autophagy induced by a 0.4mT 50Hz EMF. In addition, an EMF induced autophagy balanced the cellular homeostasis to protect the cells from severe adverse biological consequences.

Silver/chitosan-based Janus particles: Synthesis, characterization, and assessment of antimicrobial activity in vivo and vitro.

Janus particles containing chitosan and silver were synthesized in an eco-friendly manner and were confirmed using transmission electron microscopy. Based on the data of the antimicrobial activity assessment, this material exhibited a higher antimicrobial activity than virgin chitosan with long-lasting antibacterial effectiveness against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Salmonella choleraesuis bacteria, as well as Botrytis cinerea fungi. The results showed that the Janus polymer could completely suppress the growth and germination of B. cinerea at a concentration of 0.02mg/mL in vitro and in vivo. This Janus polymer is an advanced functional material that combines the suitable properties of both components and could be an alternative new antimicrobial agent due to its unique chemical properties and pronounced antimicrobial activity. This material is a potential candidate for use in the food industry to prevent microbial contamination and to inhibit the growth of microorganisms, enhancing product quality and, extend shelf-life of fresh and processed agri-food products.

Effect of chitosan coatings on postharvest green asparagus quality.

Fresh postharvest green asparagus rapidly deteriorate due to its high respiration rate. The main benefits of edible active coatings are their edible characteristics, biodegradability and increase in food safety. In this study, the quality of the edible coatings based on 0.50%, 0.25% high-molecular weight chitosan (H-chitosan), and 0.50%, 0.25% low-molecular weight chitosan (L-chitosan) on postharvest green asparagus was investigated. On the basis of the results obtained, 0.25% H-chitosan and 0.50% L-chitosan treatments ensured lower color variation, less weight loss and less ascorbic acid, decrease presenting better quality of asparagus than other concentrations of chitosan treatments and the control during the cold storage, and prolonging a shelf life of postharvest green asparagus.

Antibacterial activity evaluation of quaternary chitin against Escherichia coli and Staphylococcus aureus.

Water-soluble quaternary chitin/chitosan derivatives, O-[(2-hydroxy-3-trimethylammonium)propyl chitin (OHT-chitin), N-[(2-hydroxy-3-trimethylammonium)propyl chitosan (NHT-chitosan), and N,N,N-trimethylchitosan (TMC), having identical molecular weight and same anion, were prepared, and their antibacterial activities against Escherichia coli and Staphylococcus aureus were evaluated. Their minimum inhibitory concentration (MIC) values varied from 0.04 mg/mL to 20.48 mg/mL, and the minimum bactericidal concentration (MBC) values varied from 0.16 mg/mL to 40.96 mg/mL against E. coli and S. aureus, respectively. Transmission electron microscopy (TEM) clearly showed that there was serious damage on the bacterial walls, whereas there was some dissimilarity between TMC-treated E. coli and S. aureus.

Synthesis and characteristics of chitin and chitosan with the (2-hydroxy-3-trimethylammonium)propyl functionality, and evaluation of their antioxidant activity in vitro.

Quaternary amino groups were introduced into chitin and chitosan to obtain O-(2-hydroxy-3-trimethylammonium)propyl chitin (OHT-chitin) and N-(2-hydroxy-3-trimethylammonium)propyl chitosan (NHT-chitosan). They were characterized by FTIR spectra, and GPC. The molecular weight Mw of OHT-chitin and NHT-chitosan were 8986 and 9723 with polydispersity of 1.01 and 1.0 2, respectively. Their antioxidant activities in vitro were further studied. It was found that ß-carotene-linoleic acid values of OHT-chitin and NHT-chitosan at 0.8 mg/mL were up to 91% and 96%, while that of chitosan was 40%. Based on photobleaching of α,α-diphenyl-ß-picrylhydrazyl (DPPH) at 326 nm, the DPPH inhibitory activity of OHT-chitin and NHT-chitosan was 30.9% and 31.9% at 5 mg/mL, whereas chitosan only gave 4.8%. It was also exhibited that OHT-chitin and NHT-chitosan had better antioxidant activity than chitosan according to the reducing power as well as H2O2 scavenging activity.