Immunological relevance of malonic dialdehyde. I. Preparation of Schiff's bases from lysozyme or polylysine reacted with malonic dialdehyde

Persistent immune injury induced by short-term decabromodiphenyl ether (BDE-209) exposure to female middle-aged Balb/c mice

Decabromodiphenyl ether (BDE-209), widely used in various industries for its excellent flame-retardant performance, could be enriched in humans and is closely associated with immune impairment. In addition, immune system is gradually declined and becoming more sensitive to environmental pollutants in the ageing process. Therefore, the immunotoxicity of BDE-209 (4, 40, and 400 mg/kg/day) to middle-aged mice and its recovery and susceptibility was first to be comprehensively investigated in this study. The results showed that BDE-209 exposure could lead to oxidative injury to immune organs (spleen, thymus, and liver), impair humoral (immunoglobulins), cellular (lymphopoiesis), and non-specific immunity, and disturb the expressions of the genes related to Th1/Th2 balance (T helper cells) in the middle-aged mice. In addition, Integrated Biomarker Response (IBR) indicated that BDE-209-induced immune impairment was challenging to self-regulated, and even exacerbated after 21 days of recovery and oxidative injury in immune organs could be the main reason. Furthermore, factorial analysis showed that middle-aged mice exposed to BDE-209 suffered from greater immune impairment than adult mice, and the immune impairment in aged mice is more difficult to be self-repaired than that in adult mice. It can be seen that the aged tend to suffer from BDE-209-induced persistent immune impairment and health threats.

Purification and characterization of Se-enriched Grifola frondosa glycoprotein, and evaluating its amelioration effect on As3+ -induced immune toxicity

BACKGROUND

Selenium (Se)-enriched glycoproteins have been a research highlight for the role of both Se and glycoproteins in immunoregulation. Arsenic (As) is a toxicant that is potentially toxic to the immune function and consequently to human health. Several reports suggested that Se could reduce the toxicity of heavy metals. Moreover, more and more nutrients in food had been applied to relieve As-induced toxicity. Hence glycoproteins were isolated and purified from Se-enriched Grifola frondosa, and their preliminary characteristics as well as amelioration effect and mechanism on As³⁺ -induced immune toxicity were evaluated.

RESULTS

Four factions, namely Se-GPr11 (electrophoresis analysis exhibited one band: 14.32 kDa), Se-GPr22 (two bands: 20.57 and 31.12 kDa), Se-GPr33 (three bands: 15.08, 20.57 and 32.78 kDa) and Se-GPr44 (three bands: 16.73, 32.78 and 42.46 kDa), were obtained from Se-enriched G. frondosa via DEAE-52 and Sephacryl S-400 column. In addition, Se-GPr11 and Se-GPr44 are ideal proteins that contain high amounts of almost all essential amino acids. Thereafter, the RAW264.7 macrophage model was adopted to estimate the effect of Se-GPr11 and Se-GPr44 on As³⁺ -induced immune toxicity. The results showed that the pre-intervention method was the best consequent and the potential mechanisms were, first, by improving the oxidative stress state (enhancing the activity of superoxide dismutase and glutathione peroxidase, decreasing the levels of reactive oxygen species and malondialdehyde); secondly, through nuclear factor-κB and mitogen-activated protein kinase-mediated upregulation cytokines (interleukin-2 and interferon-γ) secretion induced by As³⁺ .

CONCLUSION

The results suggested Se-enriched G. frondosa may be a feasible supplement to improve health level of the As³⁺ pollution population. © 2021 Society of Chemical Industry.

alpha-Hydroxyaldehydes, products of lipid peroxidation

Besides the well known products of lipid peroxidation, 4-hydroxy-2-nonenal, saturated and unsaturated aldehydes, 2-hydroxy-heptanal was found to be a major aldehydic product of lipid peroxidation (LPO) of n-6 fatty acids (linoleic acid 18:2, arachidonic acid 20:4). 2-Hydroxyhexanal is produced also, but only in much lower yield. 2-Hydroxyalkanales with 8,9,10 and 11 C-atoms are derived from hydroperoxides of oleic acid. An oxidation product of all unsaturated fatty acids is glyoxal. Analyses were performed after aldehyde specific derivatization reactions by GC-MS.

Malondialdehyde adducts to, and fragmentation of, apolipoprotein B from human plasma

Many recent in vitro experiments support the hypothesis that oxidatively modified low density lipoproteins (LDLs) could participate in atherogenesis. Oxidation of LDLs, especially derivatization by aldehydes originating from peroxidation of fatty acids and fragmentation of apolipoprotein (apo) B-100 which is their major apolipoprotein, probably occurs extravascularly and the presence of oxidized LDLs in the circulation is not well documented. Using electrophoresis and immunodetection techniques, we studied the structure of apo B and the presence of adducts of malondialdehyde (MDA) to this protein in LDLs from plasma of a limited population of five healthy subjects and nine patients with severe atherosclerosis. In the patient-derived LDLs, apo B appeared extensively fragmented, much more so than in those from the healthy subjects, although LDLs were isolated in all cases in the presence of antioxidants, protease inhibitors and antibiotics. Additionally, in all healthy subjects, we found a minor fragment of apo B-100, apo B-74, whereas the complementary peptide, apo B-26, was not detected; thus the presence of this minor form cannot be related to cleavage of apo B-100, either by proteolysis or by oxidation. We also present evidence that MDA adducts are present in circulating apo B and most of its fragments not only in atheromatous patients, but also in healthy subjects. Our results are consistent with the existence of oxidized LDLs in the human circulation. However, the role of non-oxidative phenomena in the structural modifications affecting apo B which are reported here cannot be excluded.

Chemistry and biochemistry of 4-hydroxynonenal, malonaldehyde and related aldehydes

Lipid peroxidation often occurs in response to oxidative stress, and a great diversity of aldehydes are formed when lipid hydroperoxides break down in biological systems. Some of these aldehydes are highly reactive and may be considered as second toxic messengers which disseminate and augment initial free radical events. The aldehydes most intensively studied so far are 4-hydroxynonenal, 4-hydroxyhexenal, and malonaldehyde. The purpose of this review is to provide a comprehensive summary on the chemical properties of these aldehydes, the mechanisms of their formation and their occurrence in biological systems and methods for their determination. We will also review the reactions of 4-hydroxyalkenals and malonaldehyde with biomolecules (amino acids, proteins, nucleic acid bases), their metabolism in isolated cells and excretion in whole animals, as well as the many types of biological activities described so far, including cytotoxicity, genotoxicity, chemotactic activity, and effects on cell proliferation and gene expression. Structurally related compounds, such as acrolein, crotonaldehyde, and other 2-alkenals are also briefly discussed, since they have some properties in common with 4-hydroxyalkenals.