The values of the relative polarity and hydrophobicity of the main classes of acyl-containing glycerolipids are calculated. These values, obtained using standard values of the elution strength of ...solvents (from
n
-hexane to water), can belong to scales of relative polarity and hydrophobicity, including a variety of organic compounds of natural origin. It is proposed to use
n
-hexadecane and water as conditional boundaries of both of these scales, covering a range from 0 to 100. Variations in the averaged levels of the relative polarity of individual classes of natural mixtures of glycerophospholipids, which can be found after their adsorption liquid chromatography separation, depend not only on the composition of the phases used but also on the molecular species composition of lipids. A close relationship of these levels with the carbon numbers of individual molecules is shown.
This review summarizes fragmentary data on the chemical characteristics of silver atoms in nanoclusters and nanoparticles and shows successful examples of their practical application for analytical ...purposes as complexes with a variety of organic natural compounds. Recent foreign publications on silver nanoparticles and their mono- or bimetallic clusters with gold atoms that exist as stable colloidal species or chemically bonded complexes with a variety of organic and inorganic sorbents and are widely applied in genetic and biochemical research in addition to clinical practice are reviewed.
The role of fatty acid ω3 acyl-lipid desaturases in low-temperature hardening (7 days at 3°C) of potato plants (
Solanum tuberosum
L
.
, cv. Yubilei Zhukova) was studied. It was found that ...transcriptions of the three genes of ω3 acyl-lipid desaturases present in the potato genome significantly differed in their response to low temperature. The content of the
FAD3
gene transcripts dramatically fell in the first day of cooling and was not restored until the end of the hardening period. The
FAD7
gene was constitutively expressed through almost the entire adaptation period. The level of the
FAD8
gene transcripts sharply increased in the first day of the hardening. The total fraction of trienoic fatty acids, which are synthesized by ω3 acyl-lipid desaturases, rose by 3% during the hardening, which is a relatively large value for potato. The hardened plants, in comparison with the unhardened ones, manifested a higher net photosynthesis/dark respiration ratio, higher (2.5-fold) concentration of soluble sugars, and stronger resistance to negative (–2 or –3°C) temperatures. It is suggested that the augmentation of the trienoic FA fraction, which are mainly localized in the thylakoid membranes of the potato chloroplasts, sustains the photosynthesis under low temperatures. Therefore, the maintenance of photosynthetic activity during the low-temperature acclimation supplies the plant with photoassimilates that are the principal sources of energy and metabolites necessary for the establishment of potato plant resistance to hypothermia.
The fatty acid composition (FAC) of fractions of organic compounds isolated from total lipids (TL) by successive solvents—chloroform, acetone, and methanol, taken as neutral lipids (NL), glycolipids ...(GL), and phospholipids (PL)—was studied by the phases of the opening of buds in plants of the
Betula
L. genus 1. It was found that the FAC of the TL fractions of opening buds of trees with morphological features of
Betula pubescens
Ehrh.,
Betula pendula
Roth, and
Betula pendula
Roth var. carelica (Mercklin) Hämet-Ahti is represented mainly by unsaturated fatty acids (USFAs) (up to 88% of the total fatty acids). Linolenic and linoleic acids (up to 55 and 47% of the total fatty acids, respectively) constituted the main share of USFAs. Palmitic acid predominated quantitatively among saturated fatty acids (SFAs) (up to 42%). The content of linoleic acid in all SL fractions decreased with the development of buds in all three birches, while the content of linolenic acid in the composition of the GL and PL fractions increased. In birches differing in morphological characteristics, the specific features of the FAC from the SL fractions of the buds were studied by the opening phases.
The qualitative composition and changes in the total fatty acid (FA) content in leaves of wild-type potato (
Solanum tuberosum
L., cv. Desnitsa) plants and plants transformed with the
desA
gene of ...Δ12-acyl-lipid desaturase from
Synechocystis
sp. PCC 6803 have been studied under cold hardening conditions (6 days at 5°С). During cold adaptation, plants of both types increase their cold resistance, but transformed plants significantly exceed control ones in relation to this parameter. Following cold hardening, the content of total etherified FA in leaves of control plants increases by almost 25% due to the decrease in the content of saturated FA and almost 30% increase in the content of polyunsaturated FA (PUFA); the growth of the PUFA content is provided mainly by linoleic (C
18:2
) and linolenic (C
18:3
) acids. Nonhardened leaves of transformed plants are characterized by the same FA content (especially C
18:3
) as the leaves of hardened control plants. Due to this fact, increase in the total FA content in hardened transformants is not so significant as in the control; at the same time, the content of linoleic (C
18:2
) acid increases by 30% (the calculated activity index for ∆12-desaturases also slightly increased). The growth of a hexadecatrienic (С
16:3
) acid content in transformed plants probably results from a low-temperature activation of potato ω3-desaturases. The obtained data allow one to suppose that the higher resistance of transformed plants compared to control ones is connected with a constitutively increased PUFA content and determines more efficient cold hardening of such plants.
Changes in fatty acid composition of chloroplast membrane lipids were investigated using tobacco (
Nicotiana tabacum
L., cv. Samsun) plants subjected to cold hardening for 6 days at 8°C. Under ...optimal growing temperature (22°C), the lipids of thylakoid membranes were characterized by elevated content of 16:3n-3 and 18:3n-3 fatty acids (FA). Compared to the lipids of chloroplast envelope membranes, the thylakoid lipids were less rich in the content of saturated, mono- and diunsaturated FA. The relative content of unsaturated FA in chloroplast membranes increased substantially during cold hardening, which was mainly due to the accumulation of 18:3n-3 FA. It is concluded that the observed changes in FA composition of chloroplast lipids during cold hardening adjust the fluidity of these membranes to the level sufficient for functioning of tobacco photosynthetic apparatus, which is a prerequisite for accumulation of assimilates and allows the hardened tobacco plants to survive under conditions of hypothermia.
The fatty acid (FA) composition of total extractable and non extractable with chloroform lipids of C. revoluta pollen was determined. Among other minor FAs, unusual Δ5 polymethylene-interrupted FA, ...Δ5, 11-octadecadienoic acid was found. This FA was found in the seed lipids of C. revoluta earlier, but it was discovered for the first time in pollen lipids.
Absolute content and composition of fatty acids (FAs) in total lipids from the buds of white birch (
Betula pubescens
Ehrh
.
), silver birch (
B. pendula
Roth), and its subspecies
B. pendula
var
. ...carelica
Merckl
.
were investigated. The examined birches differed in these characteristics calculated per gram of dry weight. The buds of Karelian birch contained reliably greater content of FAs in total lipids as compared with the buds of two other birches. Detected differences in the content of total lipid FAs in two species and one variety of birch reflect peculiarities of biosynthesis of lipid compounds and may serve as an indicator for identification of plants from the genus
Betula
L
.
New parameters are proposed that allow reliable calculation of fixed hydrophilicity values for different classes of lipids over the widest possible range, based on the elution power of solvents and ...using two compounds at the boundaries of the range as standards. The values of relative hydrophilicity are calculated from the values of relative chromatographic mobility of these types of compounds. It is established that the levels of hydrophilicity of different classes of lipids relative to the selected hexadecane–glycerol pair do not depend on the composition of the different mobile phases used in either planar or column types of liquid chromatography for the separation of complex lipid mixtures.
Fatty acid (FA) composition of lipids from leaves and differentiated fleshy strobila tissues and sporangia with spores of Cycas (
Cycas revoluta
Thumb.) after their step quantitative extraction from ...plant material was investigated. Quantitative content and qualitative composition of FAs of extractable and nonextractable leaf lipids were determined. It was established that flesh lipids of sporophylls are characterized by a high saturation level and contain a considerable proportion of saturated FAs with the usual chain length (C
12
–C
18
, 53–57%). At the same time, total amount of etherified FAs with a very long chain in lipids not extractable by the method of Zhukov and Vereshchagin exceeds several times that found in extractable lipids (~15 and ~4%, respectively). Neutral lipids of Cycas spores were represented by triacylglycerols, the lower-alkyl esters of FAs, free FAs, and sterol esters.
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