The paper presents the design of a fiber-optic microwave signal transmission line. The use of the developed design of a fiber-optic microwave transmission line allows the radar operating frequency ...range to be at least doubled. In addition, the number of functional blocks is reduced to ensure the operation of the radar in this frequency range. The results of experimental studies are presented.
The goal of this work was to study the changes in the composition and content of X TAGs during the mesocarp ripening. The main results of this study is the discovery of an almost absolute selectivity ...of incor poration of oleic acid into the middle (sn 2) and vac cenic acid into the side (sn 1 and sn 3) positions in the glycerol residues in TAGs containing oleic and vacce nic acids (O TAGs and V TAGs, respectively).
Potato (Solanum tuberosum L.) plants were transformed with the desA gene encoding Delta 12 acyl-lipid desaturase in the cyanobacterium Synechocystis sp. PCC 6803. To evaluate the efficiency of this ...gene expression in the plant, its sequence was translationally fused with the sequence of the reporter gene encoding thermostable lichenase. A comparison of native and hybrid gene expression showed that lichenase retained its activity and thermostability within the hybrid protein, whereas desaturase retained its capability of inserting the double bond in fatty acid (FA) chains and, thus, to modify their composition in membrane lipids. In most transformed plants, shoots contained higher amounts of polyunsaturated FAs, linoleic and linolenic (by 39-73 and 12-41%, respectively). The total absolute content of unsaturated FAs was also higher in transformants by 20-42% as compared to wild-type plants. When transformed plants were severely cooled (to -7 degree C), the rate of their membrane lipid peroxidation was not enhanced, whereas in wild-type plants, it increased substantially (by 25%) under such conditions. These results could indicate a higher tolerance of transformed plants to low temperatures and the oxidative stress induced by hypothermia.
Dark germination of sea buckthorn (Hippophal rhamnoides L.) seeds was characterized by an initial 3-day-long lag-period, when the contents of triacylglycerols (TAGs) and polar lipids (PLs) remained ...nearly the same due to a retardation in lipid metabolization. Subsequently, TAG content declined rapidly, and by the 10th day of germination, it did not exceed 5% of total lipids. In this case, total saturated (S) and total unsaturated (U) fatty acids (FAs), as well as various TAG types such as S₂U, SU₂, and U₃, were consumed at nearly similar relative rates. At the same time, separate TAG groups, which included one of the individual FAs, such as palmitic (P), stearic (St), oleic (O), linoleic (L), or linolenic (Le), differed from each other in the intensity of degradation. For L- and Le-TAGs, initial and final concentrations were similar, while initial concentrations of St- and O-TAGs by the 10th day of germination increased 2.3- and 1.5-fold, respectively, and as regards P-TAGs, this value decreased 3.5-fold. Thus, P-TAGs considerably exceeded other TAG groups in their consumption rate in seedlings, while St- and O-TAGs ranked below them in this respect. By the 10th day, the absolute level of PLs increased 16-fold due to a de novo formation of lipid membranes of the cells in the course of growth and differentiation of seedling tissues; this increase was accompanied by an increase in the S-FA concentration in PLs and a decrease in the amount of U-FAs.
The structure of unusual fatty acid (FA) components of triacylglycerols (TAGs) of mature sea buckthorn (Hippophae rhamnoides L.) mesocarp oil was determined by GLC and MS, and the positional-species ...composition (PSC) of these TAGs was estimated using the methods of TAG chemical deacylation, TLC, GLC, and computer calculation. It was shown that the unusual FAs comprised n-cis-Δ9-hexadecenoic, n-cis-Δ9,12-hexadecadienoic (palmitolinoleic), and n-cis-Δ11-octadecenoic (cis-vaccenic) acids. The hexadecenoic acid predominated in the oil, and in its distribution in TAGs, it was similar to the total FAs differing from them only in some prevalence in the triunsaturated TAGs and in the TAGs with a shorter acyl chain, as well as in the sn-2 position of TAGs. Palmitolinoleic (16:2) acid comprised only 5% of total FAs, and it was exclusively concentrated in the sn-2 position of TAGs. As regards its distribution between various positional types and forms of TAGs, the 16:2 acid was similar to oleate and total FAs. As compared to the total TAGs, the TAGs with 16:2 acid were characterized by a lower FA chain length as well as by a highest unsaturation. The TAGs with vaccenic acid (V-TAGs) considerably exceeded O-TAGs, i.e., the TAGs containing oleic acid, another 18:1 positional isomer, both in their content in the total TAGs and in their unsaturation. In the composition of positional types and fractions of various unsaturation, O-TAGs were similar to the total TAGs, while V-TAGs were characterized by a very unusual structure, viz., a very high triunsaturated TAG level and an extremely low concentration of 1,3-disaturated-2-monounsaturated TAGs. In addition, oleic acid, like most other unsaturated FAs, was incorporated predominantly in the sn-2 position of TAGs, while vaccenic acid, being also unsaturated, was nevertheless by 90% concentrated in the sn-1,3 positions of V-TAGs. Unusual FAs were related to each other in the mechanism of their biosynthesis. In fact, hexadecenoic acid biosynthesis produced by palmitic acid desaturation, was, on the one hand, further desaturated forming palmitolinoleic acid, and, on the other hand, converted to vaccenic acid via C2 elongation.
Coordination complexes of unsaturated
rac-1,2-diacylglycerols (DAGs) with silver ions were separated by adsorption and reversed-phase TLC (silver ion TLC and silver ion RP-TLC, respectively). During ...silver ion TLC, silver ion complexes are formed by an indeterminate number of coordination centers of various nature and only at the adsorbent surface; separation of the complexes proceeds according to an adsorption mechanism, and there is an inverse exponential relationship between DAG unsaturation and their mobility. With silver ion RP-TLC, the complexes are formed only with double bonds, only in solution, and at a 1:1 ratio; the complexes are fractionated by lipophilic partitioning between two liquid phases, and the relationship between the unsaturation of DAGs and their mobility is a direct linear one. Nevertheless, in spite of all these differences, the use of both methods demonstrated that DAG species characterized by a coiled acyl configuration always greatly exceeded in polarity those with the same unsaturation, but with the configuration close to an extended one; in the former group, this excess amounted to two- to three-fold and 30–40% for silver ion TLC and silver ion RP-TLC, respectively. In addition, for both versions of silver ion LC, these two groups of species differ from each other quantitatively, but not qualitatively, in the pattern of the relationship between the unsaturation and mobility of DAG complexes. Thus, under all conditions of silver ion LC studied here, the polarity of DAG complexes and, therefore, their mobility are conditional not only on the number of double bonds, but also on their configuration.
The content and fatty acid (FA) composition of FA neutral acylglycerols (NAG), a mixture of 1,2,3-triacyl-sn-glycerols (TAG) and 3-acetyl-1,2-diacyl-sn-glycerols (acDAG), were determined in the seeds ...and arils of fruits of 14 Euonymus L. species. On the average, the seeds exceeded the arils in the absolute and relative dry matter content 2.9- and 1.9-fold, respectively, and separate plant species greatly differed in NAG composition. The proportions of TAG in the NAG of seeds and arils were 4–5 and ~98 %, respectively. The degree of FA unsaturation in aril NAG was higher than in the seed NAG, and in acDAG—higher, than in TAG. In the NAG, 14 major FA molecular species (excluding minor FA) were found, and linoleic, oleic, palmitic, and linolenic acids were predominant. NAG of separate taxonomic units of the genus Euonymus L. differed from each other in the concentration of major FA as well as other FA. So, by using statistical analysis, it was definitely established that the species from the subgenus Euonymus were characterized by an increased content of linoleic acid, while those from the subgenus Kalonymus, by the predominance of oleic acid. Meanwhile, the species of the section Euonymus were marked by an enhanced concentration of a number of hexa- and octadecenoic FA positional isomers.
The positional‐species composition (PSC) of 3‐acetyl‐1,2‐diacyl‐sn‐glycerols (AcDAGs) from the seeds of mature fruits of 14 species of the genus Euonymus L. was established. The residues of six major ...fatty acids (FAs), palmitic (P), stearic (St), hexadecenoic (H), octadecenoic (O), linoleic (L), and linolenic (Ln), were present in the AcDAGs. Here, we demonstrated that the profile of PSC of AcDAGs could serve as chemotaxonomic factor to divide euonymus species studied here into groups which completely correlate with the present day systematic of the genus. In particular, the Euonymus section greatly exceeded other sections of the Euonymus subgenus as well as the Kalonymus one in the total levels of AcDAGs positional species having one and two O residues and was characterized by significantly lesser concentrations of species with one and two L residues. Moreover, in seed, AcDAGs of almost all Euonymus species EFL values were slightly higher than EFO ones, but all EFL and EFO values were higher than 1.0, and therefore, it can be concluded that both FAs mainly esterified sn‐2‐position of the glycerol moiety and saturated FAs residues were always virtually absent in the sn‐2 position of Euonymus seed AcDAGs, as it is also the case in nearly all TAGs molecules of plant origin.
Positional-species composition (PSC) of 1,2,3-triacyl-sn-glycerols (TAG) from the arils of mature fruits of 13 species of Euonymus L. genus was established. The residues of six major fatty acids ...(FA), palmitic, stearic, hexadecenoic (H), octadecenoic (O), linoleic (L), and linolenic, were present in the TAG. PSC of TAG was determined by their partial lipase hydrolysis. By using hierarchical cluster and principal component analyses, it was definitely demonstrated that separate taxonomic units forming this genus were significantly distinguished as regards PSC of TAG. In particular, the Euonymus subgenus greatly exceeded the Kalonymus subgenus in both total content of L in TAG and in the rate of its incorporation into their mid-position, while TAG of Kalonymus were marked by a prevalence of O-TAG and sn-2-O isomers. Thus, these subgenera were significantly distinct in the rate of incorporation of O and L residues in the sn-2 position of TAG molecules. Meanwhile, the TAG from the Euonymus section species were marked by an enhanced concentration of H and the incorporation of H in UUU TAG was much more active than in other TAG types. As for positional-type composition of TAG, saturated FA were always virtually absent in the sn-2 position of Euonymus aril TAG.
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