In vivo experimental modelling of the infectious process caused by stable L forms of the causative agent of typhoid

To simulate the infectious process and to study the persistence of L-forms, rabbits and guinea pigs were infected with S. typhi stable L-forms. The materials presented in this work indicate that both subconjunctival and intraperitoneal infection led to the development of the clinically indistinct, but morphologically pronounced pathological process with characteristic localization and typical changes in the gastrointestinal tract. The typical features of the process were the generalized immunomorphological reaction of the lymphoid apparatus with the appearance of light-colored reticulomacrophagal elements, the signs of the activation of humoral and cell-mediated immunity and the formation of small epitheloidocellular granulomas. The results of the investigation indicate that the stable cultures of S. typhi L-forms are highly pathogenic and capable of inducing the infectious process in experimental animals.     

Antigenic structure of Salmonella L forms studied by an immunoferritin method

The antigenic structure of the L-forms of salmonellae (S. typhimurium and S. typhi) in comparison with that of the initial bacterial cultures and revertant cultures was studied with the use of the immunoferritin method. The L-forms of salmonellae were found to retain an insignificant amount of O-antigen, as well as to have K-antigen on the surface of the cytoplasmic membrane, but in a lesser amount than the initial strains. In the cultures reverting from the L-forms of S. typhimurium and S. typhi the quantitative and qualitative characteristics of O- and K-antigens were completely restored.     

Isolation and characteristics of a recombinant pOV13 plasmid as a vector for DNA cloning in a broad range of bacterial hosts

The hybrid plasmid pOV13 proposed as a potential vector for DNA cloning in a broad bacterial host range has been constructed on the basis of the broad host range plasmid RSF1010 and a shortened derivative of RP4, the plasmid pVZ115 serving a marker DNA fragment. The plasmid pOV13 contains the genes for streptomycin, kanamycin and tetracycline resistance and single cleavage sites for restriction endonucleases BamHI, BgIII, SalI, SmaI, PvuII, XhoI, as well as double cleavage sites for restriction endonucleases PstI and HindIII permitting one to clone DNA with insertional inactivation of genes. The physicogenetical map of the birepliconed plasmid pOV13 is presented.     

Cloning and characteristics of recA gene in Pseudomonas aeruginosa

A recA-like gene from Pseudomonas aeruginosa was cloned and identified by means of interspecific complementation of gene recA repair defect in Escherichia coli. The gene was mapped in the PvuII-HindIII Ps. aeruginosa chromosome fragment of 1.5 kbp in length. Having been recloned in pUC18 or 19 plasmids in either of possible orientations, this fragment was shown to complement three different defects of E. coli recA mutants: in repair, recombination and SOS functions.     

Elemental distribution in striated muscle and the effects of hypertonicity: Electron probe analysis of cryo sections

A method of rapid freezing in supercooled Freon 22 (monochlorodifluoromethane) followed by cryoultramicrotomy is described and shown to yield ultrathin sections in which both the cellular ultrastructure and the distribution of diffusible ions across the cell membrane are preserved and intracellular compartmentalization of diffusabler ions can be quantitated. Quantitative electron probe analysis (Shuman, H., A.V. Somlyo, and A.P. Somlyo. 1976. Ultramicros. 1:317-339.) of freeze-dried ultrathin cryto sections was found to provide a valid measure of the composition of cells and cellular organelles and was used to determine the ionic composition of the in situ terminal cisternae of the sarcoplasmic reticulum (SR), the distribution of CI in skeletal muscle, and the effects of hypertonic solutions on the subcellular composition if striated muscle. There was no evidence of sequestered CI in the terminal cisternae of resting muscles, although calcium (66mmol/kg dry wt +/- 4.6 SE) was detected. The values of [C1](i) determined with small (50-100 nm) diameter probes over cytoplasm excluding organelles over nuclei or terminal cisternae were not significantly different. Mitochondria partially excluded C1, with a cytoplasmic/ mitochondrial Ci ratio of 2.4 +/- 0.88 SD. The elemental concentrations (mmol/kg dry wt +/- SD) of muscle fibers measured with 0.5-9-μm diameter electron probes in normal frog striated muscle were: P, 302 +/- 4.3; S, 189 +/- 2.9;C1, 24 +/- 1.1;K, 404 +/- 4.3, and Mg, 39 +/- 2.1. It is concluded that: (a) in normal muscle the "excess CI" measured with previous bulk chemical analyses and flux studies is not compartmentalized in the SR or in other cellular organelles, and (b) the cytoplasmic C1 in low [K](0) solutions exceeds that predicted by a passive electrochemical distribution. Hypertonic 2.2 X NaCl, 2.5 X sucrose, or 2.2 X Na isethionate produced: (a) swollen vacuoles, frequently paired, adjacent to the Z lines and containing significantly higher than cytoplasmic concentrations of Na and Cl or S (isethionate), but no detectable Ca, and (b) granules of Ca, Mg, and P = approximately (6 Ca + 1 Mg)/6P in the longitudinal SR. It is concluded that hypertonicity produces compartmentalized domains of extracellular solutes within the muscle fibers and translocates Ca into the longitudinal tubules.     

A simple and effective separation and purification procedure for DNA fragments using Dodecyltrimethylammonium bromide

In this work we describe a simple two step separation procedure for the separation and purification of short DNA fragments. The first step involves precipitating the DNA using the cationic surfactant dodecyltrimethylammonium bromide. Dodecyltrimethylammonium bromide, unlike cetyltrimethylammonium bromide will not precipitate DNA before complexation is complete thus providing a high purity DNA. The second step involves dissolution of the DNA-dodecyltrimethylammonium complex in 75% ethanol, followed by precipitation of the Sodium-DNA salt, by titrating in a salt solution. This method is particularly suited to purification of short fragments as it does not require high salt concentrations in the ethanol precipitation step, which can be damaging for short DNA. The ability of dodecyltrimethylammonium bromide to remove ethidium bromide from intercalation sites on the DNA is also discussed     

Dynamics and genetic determination of transformation of alpha macroglobulins allogroups in different populations of domestic pigs

The results of genetic studies of transformation of alpha-macroglobullin (AM) allogroups (i.e., fixed allotype combinations) in pigs are presented. Population and hybridization studies showed that the phenomenon discovered was based on activation/inactivation of the AMI allotype expression, which depended on the genetic environment and interlocus relationships. Genetic and selection bases, as well as the significance of the transformation phenomenon described, are discussed.     

A new micromethod for mechano-chemical research.

A new micromethod to study activity of enzymes in crystalline and amorphous solid samples subjected to tension is described. Both static (up to 200%) and dynamic (with an amplitude up to 50% and frequency of 10(-3)-50 Hz) deformation may be applied to the sample during the activity measurement. Strain-induced changes in activity of thin (3-10 microns) needle-like strips (0.2-0.5 microns long), cut out of the microtome sections of cross-linked crystals of pancreatic carboxypeptidase A is measured in a droplet of substrate solution (with volume of 10(-6)-10(-9) l) with a pH-microelectrode technique.     

Age Variation of the Phenotypic Expression and the Inheritance of the IgG System of Immunoglobulin Allotypes in the Pig

The specificity of phenotypic expression and inheritance of immunoglobulin allotypes IgG1a and IgG2b in piglets are discussed. It was shown that a negative state by both these allotypes is repeatedly found among newborn piglets but is extremely rare in pigs older than one month. A model, which simultaneously describes the genetic determination of allogroups formed by allotypes IgG1a and IgG2b and the dynamics of ontogenetic expression of individual genotype by systemIgG with a result of a visually registered phenotype, was developed. Allele frequencies by system IgG were assessed in populations of domestic pigs of commercial breeds, laboratory miniature pigs, and Eurasian wild boar.     

L1 (LINE-1) retrotransposable elements provide a "fossil" record of the phylogenetic history of murid rodents

The single most difficult problem in phylogenetic analysis is deciding whether a shared taxonomic character is due to common ancestry or one that appeared independently due to convergence, parallelism, or reversion to an ancestral state. Mammalian L1 retrotransposons undergo periodic amplifications in which multiple copies of the elements are interspersed in the genome. Because these elements apparently are transmitted only by inheritance and are retained in the genome, a shared L1 amplification event can only be an inherited ancestral character. We propose that L1 amplification events can be an excellent tool for analyzing mammalian evolution and demonstrate here how we addressed several refractory problems in rodent systematics using L1 DNA as a taxonomic character.