Influence of functional groups on toxicity of carbon nanomaterials

It has been recognized that carbon nanomaterials and soot particles are toxic for human health, but the influence of functionalization on their toxicity as well as the evolution of the toxicity of carbon nanomaterials due to chemical aging in the atmosphere is still controversial. In the current study, the oxidation potential measured by dithiothreitol (DTT) decay rate and the cytotoxicity to murine macrophage cells of different functionalized carbon nanomaterials were investigated to understand the role of functionalization in their toxicities. The DTT decay rates of special black 4A (SB4A), graphene, graphene oxide, single-walled carbon nanotubes (SWCNTs), SWCNT-OH and SWCNT-COOH were 45.9±3.0, 58.5±6.6, 160.7±21.7, 38.9±8.9, 57.0±7.2 and 36.7±0.2 pmol min−1 µg−1, respectively. Epoxide was found to be mainly responsible for the highest DTT decay rate of graphene oxide compared to other carbon nanomaterials based on comprehensive characterizations. Both carboxylation and hydroxylation showed little influence on the oxidation potential of carbon nanomaterials, while epoxidation contributes to the enhancement of oxidation potential. All these carbon nanomaterials were toxic to the murine J774 cell line. However, oxidized carbon nanomaterials (graphene oxide, SWCNT-OH and SWCNT-COOH) showed weaker cytotoxicity to the J774 cell line compared to the corresponding control sample as far as the metabolic activity was considered and stronger cytotoxicity to the J774 cell line regarding the membrane integrity and DNA incorporation. These results imply that epoxidation might enhance the oxidation potential of carbon nanomaterials.

Influence of functional groups on toxicity of carbon nanomaterials: implication for toxicological evolution during atmospheric relevant aging of soot

It has been well recognized that black carbon is toxic for human health, while it is still controversial about the influence of functionalization on its toxicity as well as the evolution of its toxicity due to chemical aging in the atmosphere. In the current study, the oxidation potential measured by dithiothreitol (DTT) decay rate and the cytotoxicity to murine macrophage cells of different functionalized carbon nanomaterials, which were used as model sample of black carbon, were investigated for understanding the role of functionalization in the toxicity of black carbon. The DTT decay rates of special black 4A (SB4A), graphene, graphene oxide, single wall carbon nanotubes (SWCNT), SWCNT-OH and SWCNT-COOH were 45.9±3.0, 58.5±6.6, 160.7±21.7, 38.9±8.9, 57.0±7.2 and 36.7±0.2 pmol min−1 μg−1, respectively. Epoxide was found to be mainly responsible for the largest DTT decay rate of graphene oxide compared with other materials based on comprehensive characterizations. Both carboxylation and hydroxylation showed little influence on the oxidation potential of these materials, while epoxidation contributes to the enhancement of oxidation potential. All these carbon nanomaterials were toxic to murine J774 cell line. However, oxidized carbon nanomaterials (graphene oxide, SWCNT-OH and SWCNT-COOH) showed weaker cytotoxicity to J774 cell line compared with the corresponding control sample as far as the metabolic activity was considered and stronger cytotoxicity to J774 cell line regarding to the membrane integrity and DNA incorporation. These results imply that epoxidation might enhance the oxidation potential of black carbon during transport in the atmosphere.

ПОХІДНІ 4-ГІДРАЗИНОХІНОЛІНУ ТА ЇХ БІОЛОГІЧНА АКТИВНІСТЬ (ОГЛЯД ЛІТЕРАТУРИ)

The analysis of the literature about the biological activity of 4-hydrazinoquinolines derivatives was carried out. The variety of actions of this class of organic compounds was depicted. The most promising compounds are the ones that are associated with antimycobacterial and antimalarial activity. It is found out that the presence of substituents in the 6-th and / or 8-th position of the quinoline system increases, and in position 5 and 7 – reduces antimalarial and antibacterial activity. Studies have shown that 4-hydrazinequinolines have a fairly high toxicity, and the maintenance of electron-donating substituents leads to an increase in toxicity by 3-7 times. Their toxicity also increases in the series H <K <Na, which is associated with an increase in solubility in the above-mentioned compounds. 4-hydrazinoquinolines have a pronounced antioxidant effect, by blocking the hydrazino group on the α-ketoglutaric acid residue, the antioxidant effect is reduced, which is also due to their poor solubility in the media. Quinolinohydrazones have been investigated as transcriptase inhibitors, a retrovirus conversion enzyme. The inhibitory activity of the obtained compounds decreases in the series M-MulV> RAV-2> HIV-1. The cytotoxicity of these compounds was evaluated by means of Mosman’s analysis on a J774 cell line infected with BGC (bacille Calmette-Guerin). During this analysis, at R1 = 4-OMe, it was found to be non-cytotoxic to host cells at effective concentrations (MIK 2.5 mg / ml) to inhibit M. Tuberculosis growth. The effect of disodium salt of 2-methylquinolin-4-yl-hydrazone α-ketoglutaric acid on the synthesis of pigment in pigment-producing bacteria of the genera Pseudomonos and Serratia was studied. The maximum effect was observed at a concentration of 100 mg / L. Pigment-stimulating ability is enhanced in proportion to the concentration of 2-methyl-4-yl-hydrazone α-ketoglutaric acid in the culture medium (this trend is shown for cultures of Ps. Fluorescens iodinum, Pseudomonos fluorescens, S. Marcescens). The studied substances can be considered as the basis for the creation of new biologically active compounds.

The viability of the genetically diverse C. jejuni and C. coli strains in the macrophage J774 cell line

The viability of the genetically diverse C. jejuni and C. coli strains in the macrophage J774 cell line The intracellular survival of Campylobacter has been described within epithelial cells as well as in macrophages in vitro. The goal of this study was to estimate the viability of the genetically diverse C. jejuni and C. coli strains in the macrophage J774 cell line. Strains selected for analysis differed with regard to the occurrence of genes encoding specific virulence factors. The present work indicates that was no correlation between the source of isolates and relative intracellular survival.

Cytotoxicity of Carbon Nanotubes on J774 Macrophages Is a Purification-Dependent Effect

The cytotoxicity of the carbon nanotubes (CNTs) is an important factor for the manufacture of nanovaccines. The aim of this work was to evaluate the relationship of the purification method of CNTs in cellular toxicity using macrophages (MOs) from the J774 cell line. Viability test was performed with MTT assays at 24 h of exposure at concentrations of 0.06, 0.6, and 6 mg/L of unpurified (UP-CNTs) or purified (P-CNTs) CNTs by two different methods: (1) reflux with 3M HNO3and (2) sonication in H2SO4/HNO3. Characterization and COOH content of CNTs was performed using scanning electron microscopy, raman spectroscopy, and titration with NaHCO3. P-CNTs1had lengths >100 μm and 2.76% COOH content, while P-CNTs2had lengths >1 μm and 7% COOH content. This last particle showed a lower toxic effect. The results suggest that the lenght and COOH content are important factors in the toxicity of the CNTs.

The Effect of Interferon-γ and Lipopolysaccharide on the Growth of Francisella tularensis LVS in Murine Macrophage-like Cell Line J774

Background: Francisella tularensis, a causative agent of human tularemia, displaying the ability to proliferate inside the human cells. Aims: To evaluate the growth potential of F. tularensis LVS strain in macrophage-like cell line J774 modulated by recombinant interferon γ and E. coli derived lipopolysaccharide. Results: Stimulation of J774 cells either by interferon-γ or lipopolysaccharide alone, or especially in combination before infection F. tularensis, revealed protective effects. Higher concentrations of stimulating agents were needed to inhibit ongoing F. tularensis infection. Conclusions: Stimulation of J774 cell line by combination of interferon-γ with lipopolysaccharide inhibits the intracellular growth of F. tularensis.