O-specific L-hapten in the composition of Shigella sonnei

Along with classical lipopolysaccharide (LPS), O-specific material not precipitated by ultracentrifugation has been isolated from the water-phenol extract of S. sonnei avirulent strain 9090 possessing complete antigenic properties. The purification of O-antigen contained in the supernatant fluid has been carried out by the gel filtration of the fluid, previously treated with ribonuclease, in a column packed with Sephadex G-100. The polysaccharide nature of O-antigen thus obtained, the absence of lipid A and KDO and the low content of hexoses, or core-specific saccharides of S. sonnei LPS, in this antigen make it possible to classify this material with O-components of microbial cells, described by different authors as "native protoplasmic polysaccharide" or "L-hapten" and formed by polymers of LPS O-side chains. The content of this component in S. sonnei strains under study is, on the average, 2.5% of the weight of dry microbial substance. L-hapten preparations obtained in the course of our investigations have been found to contain two O-specific antigens detected by immunoelectrophoresis and immunodiffusion, as well as by sedimentation in saccharose gradient, where they form peaks corresponding to 4.3 S and 10.8 S. This polysaccharide O-antigen is supposed to be capable of interaction with ribosomal particles and suitable for use as a component of ribosomal dysentery vaccines.     

Detection of somatic mosaicism in humans using polymerase chain reaction with random primers

Using the method PCR amplification with random primers, DNA samples from human embryonic organs and tissues were examined. Among 27 oligonucleotide primers tested, 10 primers, producing stable, well-reproducible profiles of amplification products, were chosen for further analysis. With the help of two primers (447 and R45), the differences in RAPD PCR profiles obtained from the tissues of one embryo, were revealed. These differences were associated with the change of mobility, or with the fragment gain/loss in the RAPD profile, and could be caused either by genomic rearrangements, or mutations involving the regions of the DNA-primer pairing. Different epigenetic factors, like methylation, can also play the role in this process.     

Oxidative activity and Delta(Psi) of liver mitochondria of active and hibernating ground squirrels during various incubation conditions]

A comparative analysis of delta psi of liver mitochondria of active and hibernating gophers was carried out, and the effect of the decrease of the medium tonicity on the oxidase activity and delta psi of liver mitochondria of both animal groups was studied. The delta psi of hibernating gopher liver mitochondria was shown to be lower than that of active animals mitochondria and displayed a higher sensitivity to the uncoupler and some different restoration dynamics after the decline following the ADP addition. Swelling of liver mitochondria of hibernating gophers in hypotonic media or in media containing potassium acetate and a 3-fold freeze-thawing procedure resulted in the enhancement of the oxidase activities accompanied (in case of hypotonicity) by an delta psi increase and a decrease of its sensitivity to the uncoupler, 2.4-dinitrophenol. Inhibition of phospholipase A2 prevented the enhancement of the oxidase activity in all cases and the delta psi increase in hypotonic media.     

Activation of oxidative phosphorylation and energy-dependent absorption of Ca2+ and K+ ions by liver mitochondria of hibernating ground squirrels in hypotonic media]

Activation of initially suppressed oxidative phosphorylation and energy-dependent uptake of Ca2+ and K+ ions by liver mitochondria of hibernating gophers which is prevented by phospholipase A2 inhibitors, has been shown to occur in hypotonic media. Partial inhibition of the respiratory chain of liver mitochondria of active gophers by antimycin A which causes a decrease in the uncoupled respiration rate and delta psi down to values typical of mitochondria of hibernating gophers, practically exactly reproduced the suppression of oxidative phosphorylation and energy-dependent uptake of cations observed during hibernation. It was concluded that partial deenergization arising as a result of inhibition of the respiratory chain is the main and unique cause of suppression of energy-dependent functions of liver mitochondria of hibernating gophers.     

Degradation of chlorinated biphenyls and products of their bioconversion by <Emphasis Type="Italic">Rhodococcus</Emphasis> sp. B7a strain

Strain Rhodococcus sp. B7a isolated from artificially polluted soil destructs mono- and di-substituted ortho- and/or para-chlorinated biphenyls with utilization of chlorinated benzoic acids and shows high degradation activity as regards trichlorinated biphenyls. It is shown that p-hydroxybenzoic and protocatehoic acids are the products of p-chlorobenzoic acid catabolism.