Methods of chromatography and quantitative analysis of galacto- and phospholipids of plant leaves

Data in the literature on chromatography of glycerolipids of plant leaves on columns of DEAE-cellulose, Sephadex LH-20, silica gel, florisil, in a thin layer of silica gel, paper are generalized. Methods of obtaining chromatographically pure glycerolipids, their subfractionation, and the quantitative analysis of glycerolipids are described. Experimental data are presented on fractionation of lipids of potato leaves on columns of DEAE-cellulose, silica gel, on paper, and the quantitative determination of phospholipids. A method of rapid division of lipids into classes by means of their elution with silica gel KSC by different solvents is described.     

Determination and correction of aberrations in full field optical coherence tomography using phase gradient autofocus by maximizing the likelihood function

A method for numerical estimation and correction of aberrations of the eye in fundus imaging with optical coherence tomography (OCT) is presented. Aberrations are determined statistically by using the estimate based on likelihood function maximization. The method can be considered as an extension of the phase gradient autofocusing algorithm in synthetic aperture radar imaging to 2D optical aberration correction. The efficacy of the proposed method has been demonstrated in OCT fundus imaging with 6λ aberrations. After correction, single photoreceptors were resolved. It is also shown that wave front distortions with high spatial frequencies can be determined and corrected.     

Regulation of nitrogen metabolism in gram-positive bacteria

A search for new members of the TnrA and GlnR regulons, responsible for assimilation of nitrogen in Gram-positive bacteria, was performed. Common regulatory signals with consensus sequences ATGTNAWWWWWWWTNACAT and TGTNAWWWWWWWTNACA were identified for GlnR and TnrA, respectively. The structure was described and new potential members were found in Bacillus subtilis, B. licheniformis, Geobacillus kaustophilus, and Oceanobacillus iheyensis for the TnrA/GlnR regulons; in B. halodurans for the TnrA regulon; and in Lactococcus lactis, Lactobacillus plantarum, Streptococcus pyogenes, S. pneumoniae, S. mutans, S. agalactiae, Enterococcus faecalis, Listeria monocytogenes, Staphylococcus aureus, and St. epidermidis for the GlnR regulon.     

Evolution of differential chromosome banding]

Specific chromosome banding patterns in different eukaryotic taxons are reviewed. In all eukaryotes, chromosomes are composed of alternating bands, each differing from the adjacent material by the molecular composition and structural characteristics. In minute chromosomes of fungi and Protozoa, these bands are represented by kinetochores (Kt- (Cd-)bands), nucleolus organizers (N-bands), and telomeres as well as the euchromatin. In genomes of most fungi and protists, long clusters of tandem repeats and, consequently, C-bands were not revealed but they are likely to be found out in species with chromosomes visible under a light microscope, which are several tens of million bp in size. Chromosomes of Metazoa are usually larger. Even in Cnidaria, they contain C-bands, which are replicated late in the S phase. In Deuterostomia, chromosome euchromatin regions differ by replication time: bands replicating at the first half of the S phase alternate with bands replicating at the second half of the S phase. Longitudinal differentiation in the replication pattern of euchromatic regions is observed in all classes of Vertebrata beginning with the bony fish although the time when it developed in Deuterostomia is unknown. Apparently, the evolution of early and late replicating subdomains in Vertebrata euchromatin promoted fast accumulation of differences in the molecular composition of nucleoproteid complexes characteristic of early and late replicating bands. As a result, the more contrasting G/R and Q-banding patterns of chromosomes developed especially in Eutheria. The evolution of Protostomia and Plantae followed another path. An increase in chromosome size was not accompanied by the appearance of wide RBE and RBL euchromatin bands. The G/R-like banding within the interstitial chromosome regions observed in some representatives of Invertebrates and higher plants arose independently in different phylogenetic lineages. This banding pattern seems to be closer to that of C-banding than to the typical G/R-banding of the mammalian chromosomes.     

Fatty acid composition of glycerolipids from potato leaves

A method for rapid isolation of glyco- and phospholipids from potato leaves by a two-fold separation in a thin layer of silica gel is described. Using gas-liquid chromatography, the fatty acid compositions of monogalactosyldiglyceride, digalactosyldiglyceride, sulfolipid, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl inositol, diphosphatidyl glycerol, phosphatidic acid and non-identified lipid from potato leaves were determined. The monogalactosyl diglyceride was found to contain up to 25% of 7,10,13-hexadecatrienic acid. Trans-3-hexadecenic acid as well as phosphatidyl glycerol is a constituent component of phosphatidic acid, diphosphatidyl glycerol and the non-identified lipid.     

Prognosis of the degree of exposure of amino acid residues in globular proteins in relation to various problems of protein engineering

The algorithm was developed to predict the degree of exposure of amino acid residues in globular proteins. This algorithm combined with standard discriminant analysis methods was used for evaluation of the accessibility of Lys and Arg residues for trypsin-like proteases attack. The procedure can be useful for a computer-aided design of prolonged-action protein drug preparations.     

Analysis of macrophage heterogeneity by their phagocytic activity

Heterogeneity of resident peritoneal macrophages was studied as revealed by their phagocytosis and binding of sheep erythrocytes opsonized by specific rabbit IgG. It has been shown that the macrophage heterogeneity is due to the presence of active and inactive cellular subpopulations. A mathematical model, based on the Poisson fitting of experimental histograms, was elaborated for the analysis of subpopulation composition of macrophage pool in the test of rosette formation and phagocytosis. The validity of the model was supported by physicochemical isolation of the macrophage subpopulation which was inactive in erythrocyte binding. The macrophage pool was separated into fractions by absorption--elution at different temperatures. Active and inactive macrophage subpopulations were found in all the fractions but in different ratios.