IMPRINTING EFFECTS OF THREE AMINO ACIDS (ALANINE,LYSINE AND GLYCINE) AND THEIR OLIGOPEPTIDES INTETRAHYMENA PYRIFORMIS. DATA FROM THE HORMONE AND HORMONE RECEPTOR EVOLUTION

Hormonal imprinting takes place at the first encounter of the hormone and receptor, and results in a changed binding capacity and reaction of the cell and its progeny generations. The imprinting effect of three amino acids and their oligopeptides is studied using fluorescent-labelled peptides. Glycine and lysine could provoke positive imprinting (increased binding in the progeny generations) for their own peptides, but alanine could not. Mostly positive imprinting was provoked by glycine and lysine peptides for their own peptides of different chain length. The optimal chain length provoking self-imprinting was four for glycine, two for lysine and three for alanine. Except in this case, alanine was neutral or provoked mostly negative imprinting. After reaching the optimal chain length, there is a decline in binding. Evolutionary conclusions are discussed.     

Modeling of adaptations to physical training by using a recursive least squares algorithm

Busso, Thierry, Christian Denis, Régis Bonnefoy,André Geyssant, and Jean-René Lacour. Modeling ofadaptations to physical training by using a recursive least squaresalgorithm. J. Appl. Physiol. 82(5):1685-1693, 1997.The present study assesses the usefulnessof a systems model with time-varying parameters for describing theresponses of physical performance to training. Data for two subjectswho undertook a 14-wk training on a cycle ergometer were used to testthe proposed model, and the results were compared with a model withtime-invariant parameters. Two 4-wk periods of intensive training wereseparated by a 2-wk period of reduced training and followed by a 4-wkperiod of reduced training. The systems input ascribed to the trainingdoses was made up of interval exercises and computed in arbitraryunits. The systems output was evaluated one to five times per week byusing the endurance time at a constant workload. The time-invariantparameters were fitted from actual performances by using the leastsquares method. The time-varying parameters were fitted by using arecursive least squares algorithm. The coefficients of determinationr² were 0.875 and0.879 for the two subjects using the time-varying model, higher thanthe values of 0.682 and 0.666, respectively, obtained with thetime-invariant model. The variations over time in the model parametersresulting from the expected reduction in the residuals appearedgenerally to account for changes in responses to training. Such a modelwould be useful for investigating the underlying mechanisms ofadaptation and fatigue.

     

Similarity of maize and sorghum genomes as revealed by maize RFLP probes

Summary Densely saturated genetic maps of neutral genetic markers are a prerequisite either for plant breeding programs to improve quantitative traits in crops or for evolutionary studies. cDNA and genomic clones from maize were utilized to initiate the construction of a RFLP linkage map in Sorghum bicolor. To this purpose, an F₂ population was produced from starting parental lines IS 18729 (USA) and IS 24756 (Nigeria) that were differentiated with regard to many morphological and agronomical traits. A total of 159 maize clones were hybridized to the genomic DNA of the two parents in order to detect polymorphism: 154 probes hybridized to sorghum and 58 out of these were polymorphic. In almost all of the cases hybridization patterns were similar between maize and sorghum. The analysis of the segregation of 35 polymorphic clones in an F₂ population of 149 individuals yielded five linkage groups. The three principal ones recall regions of maize chromosomes 1, 3 and 5: in general, colinearity was maintained. A possible inversion, involving a long region of maize chromosome 3, was detected. Simulations were also performed to empirically obtain a value for the lowest number of individuals of the F₂ population needed to obtain the same linkage data.Prof. E. Ottaviano, to whom this paper is dedicated, suddenly died on June 7^th, 1991     

Intense photon emission induced by fracture of γ–irradiated Dy‐, Tm‐, Sm‐ and Mn‐doped CaSO4 single crystals

When an γ‐irradiated Dy‐, Tm‐, Sm‐ or Mn‐doped CaSO₄ crystal is impulsively deformed, two peaks appear in the ML intensity versus time curve, whereby the first ML peak is found in the deformation region and the second in the post‐deformation region of the crystals. In this study, intensities I_m1 and I_m2 corresponding to first and second ML peaks, respectively, increased linearly with an impact velocity v₀ of the piston used to deform the crystals, and times t_m1 and t_m2 corresponding to the first and second ML peaks, respectively, decreased with impact velocity. Total ML intensity initially increased with impact velocity and then reached a saturation value for higher values of impact velocity. ML intensity increased with increasing γ‐doses and size of crystals. Results showed that the electric field produced as a result of charging of newly‐created surfaces caused tunneling of electrons to the valence band of the hole‐trapping centres. The free holes generated moved in the valence band and their subsequent recombination with electron trapping centres released energy, thereby resulting in excitation of luminescent centres. Copyright © 2012 John Wiley & Sons, Ltd.     

Cell Budding from Normal Appearing Epithelia: A Predictor of Colorectal Cancer Metastasis?

Background: Colorectal carcinogenesis is believed to be a multi-stage process that originates with a localized adenoma, which linearly progresses to an intra-mucosal carcinoma, to an invasive lesion, and finally to metastatic cancer. This progression model is supported by tissue culture and animal model studies, but it is difficult to reconcile with several well-established observations, principally among these are that up to 25% of early stage (Stage I/II), node-negative colorectal cancer (CRC) develop distant metastasis, and that circulating CRC cells are undetectable in peripheral blood samples of up to 50% of patients with confirmed metastasis, but more than 30% of patients with no detectable metastasis exhibit such cells. The mechanism responsible for this diverse behavior is unknown, and there are no effective means to identify patients with pending, or who are at high risk for, developing metastatic CRC.Novel findings: Our previous studies of human breast and prostate cancer have shown that cancer invasion arises from the convergence of a tissue injury, the innate immune response to that injury, and the presence of tumor stem cells within tumor capsules at the site of the injury. Focal degeneration of a capsule due to age or disease attracts lymphocyte infiltration that degrades the degenerating capsules resulting in the formation of a focal disruption in the capsule, which selectively favors proliferating or “budding” of the underlying tumor stem cells. Our recent studies suggest that lymphocyte infiltration also triggers metastasis by disrupting the intercellular junctions and surface adhesion molecules within the proliferating cell buds causing their dissociation. Then, lymphocytes and tumor cells are conjoined through membrane fusion to form tumor-lymphocyte chimeras (TLCs) that allows the tumor stem cell to avail itself of the lymphocyte''s natural ability to migrate and breach cell barriers in order to intravasate and to travel to distant organs. Our most recent studies of human CRC have detected nearly identical focal capsule disruptions, lymphocyte infiltration, budding cells, and the formation of TLCs. Our studies have further shown that age- and type-matched node-positive and -negative CRC have a significantly different morphological and immunohistochemical profile and that the majority of lymphatic ducts with disseminated cells are located within the mucosa adjacent to morphologically normal appearing epithelial structures that express a stem cell-related marker.New hypothesis: Based on these findings and the growth patterns of budding cells revealed by double immunohistochemistry, we further hypothesize that metastatic spread is an early event of carcinogenesis and that budding cells overlying focal capsule disruptions represent invasion- and metastasis-initiating cells that follow one of four pathways to progress: (1) to undergo extensive in situ proliferation leading to the formation of tumor nests that subsequently invade the submucosa, (2) to migrate with associated lymphocytes functioning as “seeds” to grow in new sites, (3) to migrate and intravasate into pre-existing vascular structures by forming TLCs, or (4) to intravasate into vascular structures that are generated by the budding cells themselves. We also propose that only node-positive cases harbor stem cells with the potential for multi-lineage differentiation and unique surface markers that permit intravasation.     

Comparative sequence analysis of colinear barley and rice bacterial artificial chromosomes

Colinearity of a large region from barley (Hordeum vulgare) chromosome 5H and rice (Oryza sativa) chromosome 3 has been demonstrated by mapping of several common restriction fragment-length polymorphism clones on both regions. One of these clones, WG644, was hybridized to rice and barley bacterial artificial chromosome (BAC) libraries to select homologous clones. One BAC from each species with the largest overlapping segment was selected by fingerprinting and blot hybridization with three additional restriction fragment-length polymorphism clones. The complete barley BAC 635P2 and a 50-kb segment of the rice BAC 36I5 were completely sequenced. A comparison of the rice and barley DNA sequences revealed the presence of four conserved regions, containing four predicted genes. The four genes are in the same orientation in rice, but the second gene is in inverted orientation in barley. The fourth gene is duplicated in tandem in barley but not in rice. Comparison of the homeologous barley and rice sequences assisted the gene identification process and helped determine individual gene structures. General gene structure (exon number, size, and location) was largely conserved between rice and barley and to a lesser extent with homologous genes in Arabidopsis. Colinearity of these four genes is not conserved in Arabidopsis compared with the two grass species. Extensive similarity was not found between the rice and barley sequences other than within the exons of the structural genes, and short stretches of homology in the promoters and 3' untranslated regions. The larger distances between the first three genes in barley compared with rice are explained by the insertion of different transposable retroelements.     

In vivo gene electrotransfer into skeletal muscle: effects of plasmid DNA on the occurrence and extent of muscle damage

BACKGROUND: Understanding the mechanisms underlying gene electrotransfer muscle damage can help to design more effective gene electrotransfer strategies for physiological and therapeutical applications. The present study investigates the factors involved in gene electrotransfer associated muscle damage. METHODS: Histochemical analyses were used to determine the extent of transfection efficiency and muscle damage in the Tibialis anterior muscles of Sprague-Dawley male rats after gene electrotransfer. RESULTS: Five days after gene electrotransfer, features of muscle degeneration and regeneration were consistently observed, thus limiting the extent of transfection efficiency. Signs of muscle degeneration/regeneration were no longer evident 21 days after gene electrotransfer except for the presence of central myonuclei. Neither the application of electrical pulses per se nor the extracellular presence of plasmid DNA per se contributed significantly to muscle damage (2.9 +/- 1.0 and 2.1 +/- 0.7% of the whole muscle cross-sectional area, respectively). Gene electrotransfer of a plasmid DNA, which does not support gene expression, increased significantly muscle damage (8.7 +/- 1.2%). When plasmid DNA expression was permitted (gene electrotransfer of pCMV-beta-galactosidase), muscle damage was further increased to 19.7 +/- 4.5%. Optimization of cumulated pulse duration and current intensity dramatically reduced gene electrotransfer associated muscle damage. Finally, mathematical modeling of gene electrotransfer associated muscle damage as a function of the number of electrons delivered to the tissue indicated that pulse length critically determined the extent of muscle damage. CONCLUSION: Our data suggest that neither the extracellular presence of plasmid DNA per se nor the application of electric pulses per se contributes significantly to muscle damage. Gene electrotransfer associated muscle damage mainly arises from the intracellular presence and expression of plasmid DNA.