Transmembrane lipid transport between lecithin liposomes and neuroblastoma C1300 N18 cells

The method of double isotopic labels was used to study dynamics of lipid metabolism between neuroblastoma C 1300 N 18 A 1 cells and lecithin liposomes which contained 4.5-5 mumol of lecithin in 1 ml of the suspension. The cell lipids were labelled by radioactive carbon and cultivated on the medium with [1-14C] sodium acetate, phosphatidylcholine of liposomes was labelled by tritium. It is shown that 15-30 min long incubation with liposomes causes a sharp decrease of the cholesterol esters amount with a simultaneous fall of the free cholesterol level. The total content of phospholipids in this case remains unchanged though there occurs the noticeable exchange of labelled phospholipids between cells and liposomes. The cholesterol content in the plasma membranes of cells lowers sharply. The neuroblastoma cells are able to compensate arising changes in the cholesterol level for 45-60 min after which they progressively die. 90 min later only an insignificant part of the population (about 10% of cells) is retained.     

The usage of marker traits in plants for evaluation of resistance of the winter wheat to pest insects

A new method of selection of the winter wheat varieties has been tested for resistance to the pest insects' complex by the traits of plants that are the markers of plant resistance. It makes it possible to use this method from year to year independently of the pests' density.     

Intravital imaging of fluorescent markers and FRET probes by DNA tattooing

Background  

Advances in fluorescence microscopy and mouse transgenesis have made it possible to image molecular events in living animals. However, the generation of transgenic mice is a lengthy process and intravital imaging requires specialized knowledge and equipment. Here, we report a rapid and undemanding intravital imaging method using generally available equipment.     

Changes of nitric oxide level at different stages of primary open-angle glaucoma

The contents of NO stable metabolites in tears, and blood serum of the patients with different stages of open-angle glaucoma have been studied. The increasing of NO stable metabolite contents was found in tears, aqueous humor and blood serum during glaucoma progression. The depletion of glaucoma pathogenesis oxidative link was found at the terminal stage of the disease. The results of our investigation are proposed to be used for glaucoma diagnostic.     

Relationship between polyreactive properties of immunoglobulins and level of lipids in them

Presented paper deals with the relationship between immunoglobulin polyreactive properties and its lipid composition. Serum blood immunoglobulin fraction of an intact rabbit as an experimental model was used. Immunoglobulins (Ig) obtained by this way were transformed into polyreactive immunoglobulins (PRIg) by treatment with chaotropic agent KSCN or reactive oxygen species (ROS) with usage of Fe2+, EDTA and ascorbic acid. It was demonstrated that native Ig were able to bind with immobilized antigen (ovalbumin) and this ability dramatically increased after transformation of Ig into PRIg. The high immunoreactivity of PRIg was associated with marked fall (by 2-3 fold) of total phospholipids as well as individual ones--sphingomyelin and phosphatidylcholine. The main fatty acids of the Ig and PRIg phospholipid fractions in the sequence to decreasing decrease were stearic, palmitic, oleic and linoleic acids. The treatment of Ig by chaotropic agent and ROS led to decrease of stearic acid and enhancement of oleic, linoleic and arachidonic acids. The level of free cholesterol of Ig did not differ from that of PRIg. At the same time the content of cholesterol esters of PRIg was substantially diminished if compare with Ig. The main fatty acids of the Ig and PRIg cholesterol ester fraction in the sequence to decreasing were arachidonic, stearic, oleic, linoleic and palmitoleic acids. Transformation of Ig into PRIg was accompanied by enhancement of stearic acid level and loss of docosapentaenoic, arachidonic and palmitoleic acids. The results presented here support the idea about non peroxidative manner of the phospholipid and cholesterol ester extrusion from Ig molecule under its transformation into PRIg. Rather the last process could be explained by the term of concurrent physico-chemical interaction of Ig molecule with chaotropic agent or ROS leading to fall of lipid content. The presented data for the first time provide us an opportunity to conclude that transformation of Ig into PRIG is associated with the marked loss of essential phospholipids and cholesterol esters by the Ig molecule. The probable implication of this process in development of immune imbalance under certain diseases associated with oxidative stress have been discussed.     

Inhibition of mouse spleen inorganic pyrophosphatase by methylene diphosphonic acid]

Some properties of mouse spleen cytosol inorgainc pyrophosphatase (PPi-ase) (E. C. 3.6.1.1) as well as the effect of methylene diphosphonic acid (PCP) on the PPi-ase activity were studied. Specific staining for the enzyme PAAG disc-electrophoresis was developed; it was shown that the PPi-ase formed only one band in 7.5% PAAG. The enzyme pH optimum being 8.0, the optimal [Mg++]/[PPi] ratio was about 2; Km =7.7x10(-4) M, Vmax=0.77 mkM. min-1. mg protein-1. PCP was shown to competitively inhibit the pyrophosphatase reaction, Ki=2.5x10(-4) M +/- 0.2x10(-4) M.     

Cubic exact solutions for the estimation of pairwise haplotype frequencies: implications for linkage disequilibrium analyses and a web tool 'CubeX'

Background  

The frequency of a haplotype comprising one allele at each of two loci can be expressed as a cubic equation (the 'Hill equation'), the solution of which gives that frequency. Most haplotype and linkage disequilibrium analysis programs use iteration-based algorithms which substitute an estimate of haplotype frequency into the equation, producing a new estimate which is repeatedly fed back into the equation until the values converge to a maximum likelihood estimate (expectation-maximisation).     

Distribution of transfer RNA genes in thePisum sativum chloroplast DNA

Purified chloroplast tRNAs were isolated fromPisum sativum leaves and radioactively labeled at their 3′ end using tRNA nucleotidyl transferase and α³²P-labeled CTP. Pea ctDNA was fragmented using a number of restriction endonucleases and hybridized with thein vitro labeled chloroplast tRNAs by DNA transfer method. Genes for tRNAs have been found to be dispersed throughout the chloroplast genome. A closer analysis of the several hybrid regions using recombinant DNA plasmids have shown that tRNA genes are localized in the chloroplast genome in both single and multiple arrangements. Two dimensional gel electrophoresis of total ct tRNA have identified 36 spots. All of them have been found to hybridize withPisum sativum ctDNA. Using recombinant clones, 30 of the tRNA spots have been mapped inPisum sativum ctDNA.     

Revealing pancrustacean relationships: Phylogenetic analysis of ribosomal protein genes places Collembola (springtails) in a monophyletic Hexapoda and reinforces the discrepancy between mitochondrial and nuclear DNA markers

Background  

In recent years, several new hypotheses on phylogenetic relations among arthropods have been proposed on the basis of DNA sequences. One of the challenged hypotheses is the monophyly of hexapods. This discussion originated from analyses based on mitochondrial DNA datasets that, due to an unusual positioning of Collembola, suggested that the hexapod body plan evolved at least twice. Here, we re-evaluate the position of Collembola using ribosomal protein gene sequences.