305,247 research outputs found
Assignment of the Equus caballus interleukin 8 gene (IL8) to chromosome 3q14.2-> q14.3 by in situ hybridization
No full text© 2006 S. Karger AG, BaselNergadze, S.G. ; Magnani, E. ; Attolini, C. ; Bertoni, L. ; Adelson, D.L. ; Cappelli, K. ; Verini Supplizi, A. ; Giulotto, E
Micro-Raman mapping of the strain field in GaAsN/GaAsN:H planar heterostructures: A brief review and recent evolution
No full textRaman scattering is an effective tool for the investigation of the strain state of crystalline solids. In this brief review, we show how the analysis of the GaAs-like longitudinal optical phonon frequency allowed to map the strain behavior across interfaces in planar heterostructures consisting of GaAsN wires embedded in GaAsN:H matrices. Moreover, we recently showed how the evolution of the longitudinal optical frequency with increasing H dose strongly depends on polarization geometry. In a specific geometry, we observed a relaxation of the GaAs selection rules. We also present new results which demonstrate how laser irradiation intensity-even at low levels-may affect the line shape of the GaAs-like spectral features in GaAsN hydrogenated materials
Le prime ricerche di Luigi Giulotto sull’effetto Ramanall’Istituto di Fisica dell’Università di Pavia
No full textQuesto articolo focalizza l’attenzione soprattutto sulla prima fase (1936-1938) delle ricerche in spettroscopia Raman che Luigi Giulotto condusse all’Istituto di Fisica dell’Università di Pavia. Si forniscono anche alcuni elementi nuovi su due fasi successive (1940-1943 e 1947-1951) di ricerche Raman che egli condusse nello stesso Istituto e che, a differenza della prima, erano già state considerate nella letteratura secondaria
Variations of DNA polymerase-alpha and -beta during prolonged stimulation of human lymphocytes
No full textStimulation of human lymphocytes with phytohemagglutinin is known to induce an increase in overall DNA polymerase activity (DNA nucleotidyltransferase; deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7). Previous work [Pedrali Noy, G., Dalpra, L. Pedrini, A. M., Ciarrocchi, G., Giulotto, E., Nuzzo, F. & Falaschi, A. (1974) Nucleic Acids Res. 1, 1183] has shown that two subsequent waves of induction of DNA polymerase can be observed in this system; a first wave occurs in parallel with the increase in DNA replication rate; a second one occurs when the DNA synthesis rate is returned to minimal levels; the second peak is parallel to a maximum in DNA ligase and DNase levels. In the present work we have measured the levels of the DNA polymerases-alpha and -beta in phytohemagglutinin-stimulated lymphocytes during a 12-day period; both enzymes are present at detectable levels at time zero; in correspondence to the peak of DNA synthesis rate (between the fourth and fifth day) a peak of DNA polymerase-alpha is observed, increasing by a factor of approximately 20-fold over the zero time value; subsequently, the level of DNA polymerase-alpha decreases in parallel with DNA synthesis rate. The DNA polymerase-beta is also increased in correspondence to the peak in DNA synthesis rate, but reaches its maximum at later times, between the eighth and tenth day of incubation. The capacity of stimulated lymphocytes to perform repair synthesis following UV damage was measured in the same cells used for the enzyme activity determinations; this capacity also shows two maxima: a first one correlated with the peak in DNA replication rate, and a second one correlated with the peak of DNA polymerase-beta. These data suggest a certain tendency to the specialization of functions in human cell DNA polymerases; the alpha-enzyme seems mainly correlated with DNA replication, whereas the beta-enzyme seems more correlated with the ability of the cell to perform repair type synthesis
The Unique DNA Sequences Underlying Equine Centromeres
No full textCentromeres are highly distinctive genetic loci whose function is specified largely by epigenetic mechanisms. Understanding the role of DNA sequences in centromere function has been a daunting task due to the highly repetitive nature of centromeres in animal chromosomes. The discovery of a centromere devoid of satellite DNA in the domestic horse consolidated observations on the epigenetic nature of centromere identity, showing that entirely natural chromosomes could function without satellite DNA cues. Horses belong to the genus Equus which exhibits a very high degree of evolutionary plasticity in centromere position and DNA sequence composition. Examination of horses has revealed that the position of the satellite-free centromere is variable among individuals. Analysis of centromere location and composition in other Equus species, including domestic donkey and zebras, confirms that the satellite-less configuration of centromeres is common in this group which has undergone particularly rapid karyotype evolution. These features have established the equids as a new mammalian system in which to investigate the molecular organization, dynamics and evolutionary behaviour of centromeres
Novel cathelicidins in horse leukocytes
No full textCathelicidins are precursors of defense peptides of the innate immunity and are widespread in mammals. Their structure comprises a conserved prepropiece and an antimicrobial domain that is structurally varied both intra- and inter-species. We investigated the complexity of the cathelicidin family in horse by a reverse transcription-PCR-based cloning strategy of myeloid mRNA and by Southern and Western analyses. Three novel cathelicidin sequences were deduced from bone marrow mRNA and designated equine cathelicidins eCATH-1, eCATH-2 and eCATH-3. Putative antimicrobial domains of 26, 27 and 40 residues with no significant sequence homology to other peptides were inferred at the C-terminus of the sequences. Southern analysis of genomic DNA using a probe based on the cathelicidin-conserved propiece revealed a polymorphic DNA region with several hybridization-positive fragments and suggested the presence of additional genes. A null eCATH-1 allele was also demonstrated with a frequency of 0.71 in the horse population analyzed and low amounts of eCATH-1-specific mRNA were found in myeloid cells of gene-positive animals. A Western analysis using antibodies to synthetic eCATH peptides revealed the presence of eCATH-2 and eCATH-3 propeptides, but not of eCATH-1-related polypeptides, in horse neutrophil granules and in the secretions of phorbol myristate acetate-stimulated neutrophils. These results thus suggest that eCATH-2 and eCATH-3 are functional genes, whereas eCATH-1 is unable to encode a polypeptide
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Relationship between photorefractive activity and Raman scattering in lithium niobate crystals
No full textThe paper reports on Raman scattering experiments in pure, Mg-doped and Fe-doped single crystals of lithium niobate. The measurements were carried out in 90degrees geometry at several laser beam intensities, and in several polarization arrangements. The possible occurrence of light-induced polarization-anisotropic scattering, and its effects on Raman spectra, were checked by simultaneously measuring the time dependence of the laser beam intensity transmitted by the sample with unchanged polarization, and the time dependence of the intensity of Raman lines from vibrational modes of known symmetry. The results give no indication of any effect of photorefractive activity on Raman observations in our pure and Mg-doped samples. On the contrary, in Fe-doped lithium niobate the build-up of light-induced o-e scattering strongly affected the relative intensities of Raman lines in specific experimental arrangements. We discuss the possible application of these effects to the characterization of lithium-niobate-based materials with strong photovoltaic and photorefractive activity
Variations of DNA polymerase-alfa and -beta during prolonged stimulation of human lymphocytes.
No full textStimulation of human lymphocytes with phytohemagglutinin is known to induce an increase in overall DNA polymerase activity (DNA nucleotidyltransferase; deoxynucleosidetriphosphate:DNA deoxynucleotidyltransferase, EC 2.7.7.7). Previous work [Pedrali Noy, G., Dalprà, L. Pedrini, A. M., Ciarrocchi, G., Giulotto, E., Nuzzo, F. & Falaschi, A. (1974) Nucleic Acids Res. 1, 1183] has shown that two subsequent waves of induction of DNA polymerase can be observed in this system; a first wave occurs in parallel with the increase in DNA replication rate; a second one occurs when the DNA synthesis rate is returned to minimal levels; the second peak is parallel to a maximum in DNA ligase and DNase levels. In the present work we have measured the levels of the DNA polymerases-alpha and -beta in phytohemagglutinin-stimulated lymphocytes during a 12-day period; both enzymes are present at detectable levels at time zero; in correspondence to the peak of DNA synthesis rate (between the fourth and fifth day) a peak of DNA polymerase-alpha is observed, increasing by a factor of approximately 20-fold over the zero time value; subsequently, the level of DNA polymerase-alpha decreases in parallel with DNA synthesis rate. The DNA polymerase-beta is also increased in correspondence to the peak in DNA synthesis rate, but reaches its maximum at later times, between the eighth and tenth day of incubation. The capacity of stimulated lymphocytes to perform repair synthesis following UV damage was measured in the same cells used for the enzyme activity determinations; this capacity also shows two maxima: a first one correlated with the peak in DNA replication rate, and a second one correlated with the peak of DNA polymerase-beta. These data suggest a certain tendency to the specialization of functions in human cell DNA polymerases; the alpha-enzyme seems mainly correlated with DNA replication, whereas the beta-enzyme seems more correlated with the ability of the cell to perform repair type synthesis
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