(1) Background: The study characterized barley mutants with brassinosteroid (BR) biosynthesis and signaling disturbances in terms of the physicochemical/structural properties of membranes to enrich the knowledge about the role of brassinosteroids for lipid metabolism and membrane functioning. (2) Methods: The Langmuir method was used to investigate the properties of the physicochemical membranes. Langmuir monolayers were formed from the lipid fractions isolated from the plants growing at 20 °C and then acclimated at 5 °C or 27 °C. The fatty acid composition of the lipids was estimated using gas chromatography. (3) Results: The BR-biosynthesis and BR-signaling mutants of barley were characterized by a temperature-dependent altered molar percentage of fatty acids (from 14:0 to 20:1) in their galactolipid and phospholipid fractions in comparison to wild-type (WT). For example, the mutants had a lower molar percentage of 18:3 in the phospholipid (PL) fraction. The same regularity was observed at 5 °C. It resulted in altered physicochemical parameters of the membranes (Alim, πcoll, Cs−1). (4) Conclusions: BR may be involved in regulating fatty acid biosynthesis or their transport/incorporation into the cell membranes. Mutants had altered physicochemical parameters of their membranes, compared to the WT, which suggests that BR may have a multidirectional impact on the membrane-dependent physiological processes.

The development of nanotechnology has led to the increased production of zinc oxide nanoparticles (ZnO‐NPs) and their application in a wide variety of everyday products. It creates the need for a full assessment of their safety for humans. The aim of the study was to assess the toxic effects of ZnO‐NPs on model human cells of the immune system: U‐937, HL‐60, HUT‐78, and COLO‐720L. Particular attention was paid to the direct interaction of the nanoparticles with membrane lipids and the role of zinc ions in the mechanism of their toxicity. Cell viability, lipid peroxidation, cell membrane integrity, and the amount of zinc ions released from nanoparticles were tested. Disruption in cell metabolism was noted for ZnO‐NPs concentrations from 6.25 mg/L. Contact with ZnO‐NPs caused lipid peroxidation of all cells and correlated with membrane disruption of HL‐60, HUT‐78, and COLO‐720L cells. Model monolayers (Langmuir technique) were used to assess the interaction of the nanoparticles with the studied lipids. Physicochemical parameters, such as the area per molecule at maximal layer compression, the pressure at which the monolayer collapses, and the static compression modulus, were calculated. The models of the HL‐60 and U‐937 cell membranes under ZnO‐NPs treatment reacted in a different way. It has also been shown that Zn2+ are not the main causative factor of ZnO‐NPs toxicity. Investigating the early stages of mechanism of nanoparticles toxicity will allow for a more complete risk assessment and development of methods for a safer synthesis of engineering nanomaterials.

In the present work, Langmuir monolayers were used to study the interaction of putrescine (a cationic antioxidant) with anionic charged membranes (1,2-dioleoyl-sn-glycerol-3-phosphate) under oxidative stress caused by the presence of ozone in the water phase. Calcium ions and acidic environment were used to compare the electrostatic and antioxidant effects of putrescine with those of an inorganic cation. It has been shown that the main role of putrescine in protecting systems against oxidation is its rapid reaction with ROS. The initial rate of ROS neutralization rose as the concentration of putrescine increased. No such reaction was observed for calcium ions. The consequence of putrescine’s ozone removal was lesser lipid destruction that depended on the pH conditions.

Purpose Due to its physiological importance as a micronutrient, manganese supplementation requires taking into account the possibility of overdosing, which is associated with the initiation of stressogenic effects in plant cells. The use of nanoparticles may reduce the amount of Mn ion administered, especially during foliar treatment. Hence, the aim of the research was to demonstrate the mechanism of action of MnNPs on plant cells and to determine the extent of the stress-inducing reaction of these NPs. Methods A response to manganese nanoparticles was studied in seedlings of two wheat cultivars, model system of plant cell membranes and compared with cell lines (U-937, HL-60, HUT-78, COLO-720L). The nanoparticles (MnNPs as Mn3O4) were at the same concentrations (125 and 250 mg/mL) by foliar application to plants and to the cell culture media. Results The administration of NPs enhanced the content of Mn in plant cells, indicating its penetration through the leaf surface and initiated the oxidative stress measures as an increase in enzyme activity, starch accumulation, and a decrease in chlorophyll synthesis. Moreover, a rise in the electrokinetic potential of the chloroplast membrane surface and the reconstruction of their hydrophobic parts toward an increase in fatty acid saturation was found. Conclusion The study demonstrated that the stress response in plant cells was initiated up to 250 mg/mL of MnNPs. The same concentration resulted in reduction of cell viability, especially in U-937 line.

Three-finger toxins are naturally occurring proteins in Elapidae snake venoms. Nowadays, they are gaining popularity because of their therapeutic potential. On the other hand, these proteins may cause undesirable reactions inside the body′s cells. A full assessment of the safety of Naja ashei venom components for human cell application is still unknown. The aim of the study was to determine the effect of the exogenous application of three-finger toxins on the cells of monocytes (U-937) and promyelocytes (HL-60), with particular emphasis on the modification of their membranes under the influence of various doses of 3FTx protein fraction (0–120 ng/mL). The fraction exhibiting the highest proportion of 3FTx proteins after size exclusion chromatography (SEC) separation was used in the experiments. The structural response of cell membranes was described on the basis of single-component and multi-component Langmuir monolayers that mimicked the native membranes. The results show that the mechanism of protein–lipid interactions depends on both the presence of lipid polar parts (especially zwitterionic type of lipids) and the degree of membrane saturation (the greatest-for unsaturated lipids). The biochemical indicators reflecting the tested cells (MDA, LDH, cell survival, induction of inflammation, LD50) proved the results that were obtained for the model.