Fatty acid composition of individual polar lipid classes from marine macrophytes

Major glycolipids [monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfoquinovosyldiacylglycerol (SQDG)) and phospholipids (phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG)] as well as betaine lipid 1,2-diacylglycero-O-4'-(N,N,N-tri-methyl)-homoserine (DGTS) were isolated from Anfeltia tobuchiensis (Rhodophyta), Laminaria japonica, Sargassum pallidum (Phaeophyta), Ulva fenestrata (Chlorophyta) and Zostera marina (Embriophyta), harvested in the Sea of Japan. GC analysis of their fatty acid (FA) composition revealed that the n-6 polyunsaturated FAs (PUFAs) shared the most part of the sum of n-6 and n-3 PUFAs in PC and PE compared with glycolipids and PG. In algae, it was related to the prevalence of 20:4n-6 over 20:5n-3 in non-photosynthetic lipids. Percentage of n-6 PUFAs as well as the sum of n-3 and n-6 PUFAs decreased in the following sequence: PC-->PE-->PG. The saturation increased in the lines of MGDG-->DGDG-->SQDG and PC-->PE-->PG. PG was close to SQDG by the level of saturation. Distribution of C(18) and C(20) PUFAs in polar lipids depended on taxonomic position of macrophytes. Balance between C(18) and C(20) PUFAs was preferably shifted to the side of C(20) PUFAs in PC and PE that was observed in contrast to glycolipids and PG from L. japonica containing both series of FAs. The set of major FAs of polar lipid classes can essentially differ from each other and from total lipids of macrophytes. For example, MGDG was found to accumulate characteristic fatty acids 16:4n-3, 16:3n-3, 18:3n-6 and 18:4n-3, 20:3n-6 in U. fenestrata, Z. marina, L. japonica and S. pallidum, respectively.     

Action of Iron Nitrosyl Complexes,NO Donors,on the Activity of Sarcoplasmic Reticulum Ca<Superscript>2+</Superscript>-ATPase and Cyclic Guanosine Monophosphate Phosphodiesterase

The effect of iron nitrosyl complexes, NO donors, of a general formula [Fe₂(L)₂(NO)₄] with functional sulfur-containing ligands (L-3-nitro-phenol-2-yl, 4-nitro-phenol-2-yl, or 1-methyl-tetrazol-5-yl) on the activity of sarcoplasmic reticulum Ca²⁺-ATPase and cyclic guanosine monophosphate phosphodiesterase (cGMP PDE) was studied. The test complexes uncoupled the hydrolytic and transport functions of Ca²⁺- ATPase, thus disturbing the balance of Ca²⁺ ions in cells, which may affect the formation of thrombi and adhesion of metastatic cells to the endothelium of capillaries. They also inhibited the activity of cGMP PDE, thereby contributing to the accumulation of the second messenger cGMP. The studied iron nitrosyl complexes can be considered as potential drugs.     

Phospholipid and Fatty Acid Composition of Phosphatidylcholine and Phosphatidylethanolamine in the Black Plaice <Emphasis Type="Italic">Pleuronectes obscura</Emphasis> during Thermoadaptation

The phospholipid (PL) and fatty acid (FA) composition of major membrane lipid constituents, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), as well as the cholesterol/phospholipid (CL/PL) ratio were assayed in the muscles, gills and liver of the black plaice Pleuronectes (Liopsetta) obscura at different ambient temperatures (18, 9 and 0°C). PL and CL were shown to be actively involved in adaptation of the fish to changes in the seawater temperature. As temperature declines, the monounsaturated FA (MUFA) level increases while the polyunsaturated FA (PUFA) fraction in gills and liver PC and PE, on the contrary, decreases, resulting in diminished functional activity of the fish. However, in muscles this correlation is lacking. The PC and PE composition was shown to be organ- and ambient temperature-dependent. Major PC forms are saturated FA (SFA)/PUFA and MUFA/PUFA composed of a relatively small number of major molecular species. A temperature drop results in an increased SFA/PUFA level and decreased MUFA/PUFA and PUFA/PUFA levels in muscles and gills, and this may promote a drop in the viscosity of the outer lipid monolayer of membranes and in their functional activity. In contrast to PC, the PE composition in all organs tested is characterized by a decrease in the SFA/ PUFA level and an increase in MUFA/PUFA and PUFA/PUFA levels. Such changes promote the retention of functional activity of the inner lipid monolayer of membranes and are not synchronized with rearrangements in their outer monolayer. Due to intermolecular transfer of acyl radicals at a constancy of their composition, functional rearrangement of the lipid matrix appears to be achieved through changes in the membrane viscosity. Our data support the idea that different adaptation strategies in fish are driven by certain sets of PL molecular species.     

The inhibitory effect of dinitrosyl iron complexes (NO donors) on myeloperoxidase activity

The effect of synthetic analogues of dinitrosyl mononuclear iron complexes (DNICs) with functional sulfur-containing ligands (NO donors) on the activity of myeloperoxidase (MPO) was studied, and their efficiency was evaluated. It was shown that the enzyme MPO is the molecular target of DNICs. It was found that six DNICs inhibited the activity of MPO and one compound potentiated it. The evaluation of their efficiency showed that two DNICs effectively inhibited the activity of MPO by 50% at IC₅₀ = 2 × 10^–4 M and IC₅₀ = 5 × 10^–7 M.     

Effects of copper and cadmium ions on the physicochemical properties of lipids of the marine bacterium <Emphasis Type="Italic">Pseudomonas putida</Emphasis> IB28 at different growth temperatures

The phospholipid and fatty acid composition and thermotropic behavior of total lipids were studied in the metal-accumulating marine strain Pseudomonas putida IB28 grown in the presence of Cu²⁺ and Cd²⁺ at 4 and 24°C. Despite the changes in acidic lipid content, unsaturated/saturated fatty acid ratio, and cyclopropane fatty acid level, the temperature range of calorimetric phase transitions of bacterial total lipids was slightly altered under these factors. The suppressive action of heavy metals on bacterial growth is attributable to the phase separation of lipids and, as a consequence, to a sharp increase in the ion permeability of the lipid bilayer. The increase in acidic phospholipid level under the influence of Cu²⁺ and Cd²⁺, especially at 24°C, is likely to be indicative of their complexation with heavy metal ions.     

Seasonal changes of fatty acid composition and thermotropic behavior of polar lipids from marine macrophytes

Major glyco- and phospholipids as well as betaine lipid 1,2-diacylglycero-O-4'-(N,N,N-tri-methyl)-homoserine (DGTS) were isolated from five species of marine macrophytes harvested in the Sea of Japan in summer and winter at seawater temperatures of 20-23 and 3 degrees C, respectively. GC and DSC analysis of lipids revealed a common increase of ratio between n-3 and n-6 polyunsaturated fatty acids (PUFAs) of polar lipids from summer to winter despite their chemotaxonomically different fatty acid (FA) composition. Especially, high level of different n-3 PUFAs was observed in galactolipids in winter. However, the rise in FA unsaturation did not result in the lowering of peak maximum temperature of phase transition of photosynthetic lipids (glycolipids and phosphatidylglycerol (PG)) in contrast to non-photosynthetic ones [phosphatidylcholine (PC) and phosphatidylethanolamine (PE)]. Different thermotropic behavior of these lipid groups was accompanied by higher content of n-6 PUFAs from the sum of n-6 and n-3 PUFAs in PC and PE compared with glycolipids and PG in both seasons. Seasonal changes of DSC transitions and FA composition of DGTS studied for the first time were similar to PC and PE. Thermograms of all polar lipids were characterized by complex profiles and located in a wide temperature range between -130 and 80 degrees C, while the most evident phase separation occurred in PGs in both seasons. Polarizing microscopy combined with DSC has shown that the liquid crystal - isotropic melt transitions of polar lipids from marine macrophytes began from 10 to 30 degrees C mostly, which can cause the thermal sensitivity of plants to superoptimal temperatures in their environment.     

Dynamics of the mechanical properties of drops of biological liquids during drying as a reflection of the features of selfassembly of their components from the nano- to microlevel

It has been shown that the dynamics of the molecular self-assembly of the components of liquids drying in the form of drops on a solid moistened surface contains information about their composition and structure. The physical mechanisms of this phenomenon have been considered. A method of recording this dynamics and retrieving useful information has been suggested. Examples of using this method in medicinal diagnosis and the assessment of the quality of food products, drugs, and liquids of domestic appliance are given.     

Thermotropic behavior of sphingophospholipids of marine invertebrates

Thermotropic behavior of total fraction of sphingomyelin (SM) and its forms, sphingomyelin that contains acyl residues of normal fatty acids (SMN) and sphingomyelin that is Nacylated predominantly with hydroxy acids (SMH) as well as of ceramideaminoethylphosphonate (CAEP) has been studied by the method of differential scanning microcalorimetry. It was shown that chromatographically pure anhydrous sphingophospholipids isolated from different species of marine invertebrates have no phasic transitions in the entire temperature interval of scanning, from-100 to 100°C, whereas partially hydrated samples or mixtures of sphingophospholipids with glycerophospholipids (phosphatidylcholine or phosphatidylethanolamine isolated from corresponding marine invertebrates had phasic transitions in a large temperature range with thermoabsorption maxima in the areas of -40–20°C and 20–80°C. It is suggested that sphingophospholipids, as compared to marine invertebrate glycerophospholipids, have a much lower capability for self-organization, and to form regular supramolecular sphingophospholipid structures both in artificial systems and in biomembranes, such orientants as glycerophospholipids and water are necessary. Possible causes of an unusual behavior of sphingophospholipids of marine invertebrates as compared to glycerophospholipids are discussed.