Humoral factors of "spontaneous" mutagenesis in mammals and man

The frequency of chromosome aberrations in bone-marrow cells of mice in tissue incompatibility conflicts, and in the lymphocytes of the peripheral blood of 20 patients suffering from different allergies was studied. It was established that in mice, during allograft rejection, i.e. on the 10th–15th days after grafting of allogeneic skin, the frequency of cells with chromosome aberrations increases significantly up to 12–15% against 4–5% in the control. On the 20th day after grafting, the level of chromosome aberrations falls back to the control level. In allergic patients the frequency of cells with chromosome aberrations was 10.7% (4–22%). In numerous control subjects this value did not exceed 2%. The highest level of aberrations was found during the acute stage of the disease especially in patients in the state of anaphylactic shock. No correlation was found between the frequency of aberrant cells and the action of definite allergens. The problem of the possibility of extending the above described phenomenon to non-immunocompetent cells of mammals, and of the role of immunological stress in spontaneous mutagenesis are discussed.     

A molecular characterization of the charismatic Faroe house mouse

Faroe house mice are a ‘classic’ system of rapid and dramatic morphological divergence highlighted by J. S. Huxley during the development of the Modern Synthesis. In the present study, we characterize these charismatic mice using modern molecular techniques, examining specimens from all Faroe islands occupied by mice. The aims were to classify the mice within the modern house mouse taxonomy (i.e. as either Mus musculus domesticus or Mus musculus musculus) using four molecular markers and a morphological feature, and to examine the genetic diversity and possible routes of colonization using mitochondrial (mt) control region DNA sequences and microsatellite data (15 loci). Mice on the most remote islands were characterized as M. m. domesticus and exhibited exceptionally low genetic diversity, whereas those on better connected islands were more genetically diverse and had both M. m. musculus and M. m. domesticus genetic elements, including one population which was morphologically M. m. musculus‐like. The mtDNA data indicate that the majority of the mice had their origins in south‐western Norway (or possibly southern Denmark/northern Germany), and probably arrived with the Vikings, earlier than suggested by Huxley. The M. m. musculus genetic component appears to derive from recent mouse immigration from Denmark. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 471–482.     

Identification of structural DNA variations in human cell cultures after long-term passage

Random amplified polymorphic DNA (RAPD) analysis was adapted for genomic identification of cell cultures and evaluation of DNA stability in cells of different origin at different culture passages. DNA stability was observed in cultures after no more than 5 passages. Adipose-derived stromal cells demonstrated increased DNA instability. RAPD fragments from different cell lines after different number of passages were cloned and sequenced. The chromosomal localization of these fragments was identified and single-nucleotide variations in RAPD fragments isolated from cell lines after 8–12 passages were revealed. Some of them had permanent localization, while most variations demonstrated random distribution and can be considered as de novo mutations.     

Stimulation of bursting in pre-Bötzinger neurons by Epac through calcium release and modulation of TRPM4 and K-ATP channels

The exchange factor directly activated by cAMP (Epac) can couple cAMP production to the activation of particular membrane and cytoplasmic targets. Using patch-clamp recordings and calcium imaging in organotypic brainstem slices, we examined the role of Epac in pre-B?tzinger complex, an essential part of the respiratory network. The selective agonist 8-(4-chlorophenylthio)-2'-O-methyl-cAMP (8-pCPT) sensitized calcium mobilisation from inositol-1,4,5-trisphosphate-sensitive internal stores that stimulated TRPM4 (transient receptor potential cation channel, subfamily M, Melastatin) channels and potentiated the bursts of action potentials. 8-pCPT actions were abolished after inhibition of phospholipase C with U73122 and depletion of calcium stores with thapsigargin. Caffeine-sensitive release channels were not modulated by 8-pCPT. Epac inhibited ATP-sensitive K(+) channels that also led to the enhancement of bursting by 8-pCPT. Bursting activity, spontaneous calcium transients and activity of TRPM4 and ATP-sensitive K(+) channels were potentiated after brief exposures to bradykinin and incubation with wortmannin produced opposite effects that can be explained by changes in phosphatidylinositol 4,5-bisphosphate levels. 8-pCPT stimulated the respiratory motor output in functionally intact preparations and the effects of bradykinin and wortmannin were identical to those observed in organotypic slices. The data thus indicate a novel pathway of controlling bursting activity in pre-B?tzinger complex neurons through Epac that can involved in reinforcement of the respiratory activity by cAMP.     

Genetic Analysis of Giardia from Hoofed Farm Animals Reveals Artiodactyl-Specific and Potentially Zoonotic Genotypes

ABSTRACT. Thirty one Giardia isolates, established from six species of hoofed livestock by axenic culture or growth in suckling mice, were compared genetically by analysis of DNA amplified from loci encoding variant surface proteins or the enzyme glutamate dehydrogenase and by allozyme analysis. The isolates were heterogeneous, but all showed affinity with genetic Assemblage A-one of two major assemblages defined previously by analysis of Giardia from humans. Three distinct genotypes were evident. Ten isolates (eight axenic and two established in suckling mice) from an alpaca, pig, horse, cattle and sheep were indistinguishable from human-derived G. intestinalis belonging to a previously designated genetic group (Group I). This genotype seems to have broad host specificity, including a zoonotic potential for humans. Five isolates (two axenic and three established in suckling mice) from an alpaca, a horse and sheep had close affinity with human-derived Group I and Group I1 G. inresrinalis genotypes. The other 16 isolates (comprising both axenic and suckling mouse-propagated cultures derived from cattle, sheep, alpaca, a goat and pigs in Australia and Europe) differed from all other Giardia with "duodenalis" morphology that have been examined by these methods and they segregated as a highly distinct sublineage (referred to herein as 'Novel livestock') within genetic Assemblage A. The predominance of 'Novel livestock' genotypes in the test panel and their apparent exclusive association with artiodactyl hosts indicates that they may be confined to this group of mammals. Assemblage B genotypes, which are prevalent in humans and some other animal species, were not detected.     

The Distribution of Some Hydrolytic Enzymes in the Wheat Seed

A histochemical study of dry and germinated wheat embryos andseeds has been made to identify the sites of activity of 3'-and 5'-nucleotidases, phosphatases, lipase, and esterase. Theenzymes all showed the same distribution, with the coleorhizaas the most prominent site of activity in the dry embryo, especiallywhen compared with the adjacent roots with very low activity.Investigations of the whole seed after 24 h germination showeda very high activity in the aleurone cells and high activitiesin the scutellum and coleorhiza. The epithelium and provasculartissues of the scutellum showed moderate to low activity whilethe endosperm had little or none. Hydrolase activity also wasfound in the testa. The function of the coleorhiza. as firstfood reserve for the roots and its location at the most importantsite of water entry, is discussed.     

A high molecular weight polypeptide cross-reacting with the antibodies to the dynein heavy chain localizes to the subset of Golgi complex in higher plant cells

Antibodies were produced against fragments of the microtubule-binding domain and the motor domain of the dynein heavy chain from Dictyostelium discoideum to probe whole cell extracts of root meristem cells of wheat Triticum aestivum. In plant extracts, these antibodies cross-reacted with a polypeptide of high molecular weight (>500 kDa). The antibodies bound to protein A-Sepharose precipitated high molecular weight polypeptide from cell extracts. Immunofluorescence showed that the antibodies identified various aggregates inside cells, localized at the perinuclear area during interphase to early prophase, at the spindle periphery and polar area during mitosis, and in the interzonal region during phragmoplast development. Some aggregates were also co-labeled by markers for the Golgi apparatus. Thus, we found in higher plant cells a high molecular weight antigen cross-reacting with the antibodies to motor and microtubule-binding domains of dynein heavy chains. This antigen is associated with aggregates distributed in the cytoplasm in cell cycle-dependent manner. A subset of these aggregates belongs to the Golgi complex.