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Search Results: 1 - 10 of 22361 matches for " Roberto Piergentili "
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Evolutionary conservation of lampbrush-like loops in drosophilids
Roberto Piergentili
BMC Cell Biology , 2007, DOI: 10.1186/1471-2121-8-35
Abstract: In the male germ line of all species tested there are cells showing giant nuclei and intranuclear structures similar to those of Drosophila melanogaster primary spermatocytes. Moreover, the antibody T53-F1 recognizes intranuclear structures in primary spermatocytes of all drosophilids analyzed. Interestingly, the extent and conformation of the staining pattern is species-specific. In addition, the intense staining of sperm tails in all species suggests that the terminal localization of Loopin-1 and its orthologues is conserved. A comparison of these cytological data and the data coming from the literature about sperm length, amount of sperm tail entering the egg during fertilization, shape and extent of both loops and primary spermatocyte nuclei, seems to exclude direct relationships among these parameters.Taken together, the data reported strongly suggest that lampbrush-like loops are a conserved feature of primary spermatocyte nuclei in many, if not all, drosophilids. Moreover, the conserved pattern of the T53-F1 immunostaining indicates that a Loopin-1-like protein is present in all the species analyzed, whose localization on lampbrush-like loops and sperm tails during spermatogenesis is evolutionary conserved.A synthetic description of Drosophila melanogaster spermatogenesis comes from light microscopy studies [1-3], as well as electron microscopy studies [4-9]. At the tip of Drosophila testis a group of 8–9 staminal cells mitotically divide forming another staminal cell and a primary spermatogonium. Primary spermatogonia divide four times producing, after the last division, sixteen primary spermatocytes. Primary spermatocytes undergo a relatively long (~90 hours) maturation phase, during which they slowly increase their nuclear volume so that by the end of the growth phase they are 25–30 times larger than spermatogonia. Morphologically, at the beginning of their development primary spermatocytes are very similar to spermatogonia; however, the completely develop
How complex an intron may be? The example of the first intron of the CTP synthase gene of Drosophila melanogaster
Roberto Piergentili
Journal of Molecular Biochemistry , 2013,
Abstract: In eukaryotes, maturation of primary transcripts into mature messenger RNAs involves the elimination of parts of the gene called ‘introns’. The biological significance of introns is not yet completely understood. It has been demonstrated that introns may contain other genes, or regulatory sequences that may be involved in transcriptional control, or also being involved in alternative splicing mechanisms. However, these functions explain the role of only a small number of them, and it is very difficult to formulate any generalization. The CTP synthase gene of Drosophila melanogaster is characterized by the presence of a long first intron (approximately 7.2 kilobases) whose role is currently unknown. In the present report we analyzed in silico the content of this intron, and found that it contains at least three interesting sub-sequences. Two of them are homologous to the CTP synthase itself and to a putative nucleotide pyrophosphatase, respectively. The third is a short stretch of DNA able to fold into a thermodynamically stable hairpin and showing homology with other 19 sequences from 21 genes inside the D. melanogaster genome. These findings suggest a complex yet very accurate way of controlling gene expression inside the fruit fly.
Zooming (a little) out of the M-theory
Roberto Piergentili
Journal of Molecular Biochemistry , 2013,
Abstract:
Autosomal mutations affecting Y chromosome loops in Drosophila melanogaster
Francesca Ceprani, Grazia D Raffa, Romano Petrucci, Roberto Piergentili
BMC Genetics , 2008, DOI: 10.1186/1471-2156-9-32
Abstract: Here we report the results of a screen of 726 male sterile lines to identify novel autosomal genes controlling Y-loop function. We analyzed mutant testis preparations both in vivo and by immunofluorescence using antibodies directed against Y-loop-associated proteins. This screen enabled us to isolate 17 mutations at 15 loci whose wild-type function is required for proper Y-loop morphogenesis. Six of these loci are likely to specifically control loop development, while the others display pleiotropic effects on both loops and meiotic processes such as spermiogenesis, sperm development and maturation. We also determined the map position of the mutations affecting exclusively Y-loop morphology.Our cytological screening permitted us to identify novel genetic functions required for male spermatogenesis, some of which show pleiotropic effects. Analysis of these mutations also shows that loop development can be uncoupled from meiosis progression. These data represent a useful framework for the characterization of Y-loop development at a molecular level and for the study of the genetic control of heterochromatin.Notwithstanding the recent advances in genomics, mainly thanks to the completion of model organisms DNA sequencing, there is still a part of the eukaryote genome which is largely unknown in both structure and function: the heterochromatin. Heterochromatin is a complex of DNA and specifically associated proteins, is characterized by low gene density and the presence of highly repetitive sequences, and accounts for an important portion of the genome in all organisms. For several decades it has been considered as the repository of the so-called 'junk DNA', characterized by several selfish sequences whose only function seems that of reproducing themselves from one generation to the next. For a long time, the only exceptions were represented by the centromeres and telomeres, which are important elements for chromosome stability and proper segregation during cell division.
Tubercular disease caused by bacillus of Calmette-Guerin administered as a local adjuvant treatment of relapsing bladder carcinoma.: Pathogenetic, diagnostic and therapeutic issues, and literature review
Manfredi,Roberto; Dentale,Nicola; Piergentili,Benedetta; Pultrone,Cristian; Brunocilla,Eugenio;
Archivos Venezolanos de Farmacología y Terapéutica , 2009,
Abstract: two exemplary case reports of respiratory granulomatous infection caused by bacillus of calmette-guérin (bcg) in patients who were repeatedly treated with local, intravesical adjuvant bcg therapy for a relapsing transitional bladder carcinoma, are outlined and discussed, on the ground of the cumbersome diagnostic and differential diagnostic process (especially when a prior tuberculosis and a concurrent chronic obstructive pulmonary disease are of concern), and an updated literature revision. only four cases of respiratory bcg-itis (pulmonary tuberculosis-like forms), have been reported until now to the best of our knowledge (two of them following bladder instillation of bcg). one episode of ours represents the first described case with a dual, concomitant granulomatous localization of bcg-itis, also involving the genitourinary tract.
Tubercular disease caused by bacillus of Calmette-Guerin administered as a local adjuvant treatment of relapsing bladder carcinoma.: Pathogenetic, diagnostic and therapeutic issues, and literature review
Roberto Manfredi,Nicola Dentale,Benedetta Piergentili,Cristian Pultrone
Archivos Venezolanos de Farmacología y Terapéutica , 2009,
Abstract: Two exemplary case reports of respiratory granulomatous infection caused by bacillus of Calmette-Guérin (BCG) in patients who were repeatedly treated with local, intravesical adjuvant BCG therapy for a relapsing transitional bladder carcinoma, are outlined and discussed, on the ground of the cumbersome diagnostic and differential diagnostic process (especially when a prior tuberculosis and a concurrent chronic obstructive pulmonary disease are of concern), and an updated literature revision. Only four cases of respiratory BCG-itis (pulmonary tuberculosis-like forms), have been reported until now to the best of our knowledge (two of them following bladder instillation of BCG). One episode of ours represents the first described case with a dual, concomitant granulomatous localization of BCG-itis, also involving the genitourinary tract.
Identification of Drosophila Mitotic Genes by Combining Co-Expression Analysis and RNA Interference
Maria Patrizia Somma,Francesca Ceprani,Elisabetta Bucciarelli,Valeria Naim,Valeria De Arcangelis,Roberto Piergentili,Antonella Palena,Laura Ciapponi,Maria Grazia Giansanti,Claudia Pellacani,Romano Petrucci,Giovanni Cenci,Fiammetta Vernì,Barbara Fasulo,Michael L. Goldberg,Ferdinando Di Cunto,Maurizio Gatti
PLOS Genetics , 2008, DOI: 10.1371/journal.pgen.1000126
Abstract: RNAi screens have, to date, identified many genes required for mitotic divisions of Drosophila tissue culture cells. However, the inventory of such genes remains incomplete. We have combined the powers of bioinformatics and RNAi technology to detect novel mitotic genes. We found that Drosophila genes involved in mitosis tend to be transcriptionally co-expressed. We thus constructed a co-expression–based list of 1,000 genes that are highly enriched in mitotic functions, and we performed RNAi for each of these genes. By limiting the number of genes to be examined, we were able to perform a very detailed phenotypic analysis of RNAi cells. We examined dsRNA-treated cells for possible abnormalities in both chromosome structure and spindle organization. This analysis allowed the identification of 142 mitotic genes, which were subdivided into 18 phenoclusters. Seventy of these genes have not previously been associated with mitotic defects; 30 of them are required for spindle assembly and/or chromosome segregation, and 40 are required to prevent spontaneous chromosome breakage. We note that the latter type of genes has never been detected in previous RNAi screens in any system. Finally, we found that RNAi against genes encoding kinetochore components or highly conserved splicing factors results in identical defects in chromosome segregation, highlighting an unanticipated role of splicing factors in centromere function. These findings indicate that our co-expression–based method for the detection of mitotic functions works remarkably well. We can foresee that elaboration of co-expression lists using genes in the same phenocluster will provide many candidate genes for small-scale RNAi screens aimed at completing the inventory of mitotic proteins.
Studio di sitizzazione aeroportuale mediante analisi multi-criterio
Francesco Gentili,Emanuele Piergentili,Francesco Giuseppe Rossi,Antonino Scarelli
Aestimum , 2010,
Abstract: This study aims at implementing the multi-criteria approach in the selection of the most suitable airport site in the province of Tuscia-Viterbo. After analysing 4 sites supposed feasible in principle, collecting data and other information on the different locations, the selection criteria have been defined as: proximity to urban settlements, logistic infrastructures, visibility and air manoeuvrability, investment costs, environmental constraints, geological suitability, flood risk, seismic risk. The Analytical Hierarchical Process (AHP) has been chosen as the most suitable methodology for selecting from pairwise comparison, the most appropriate site for the airport, considering all criteria put forward. At the end of the process, the best location comes out quite clearly as one site, which keeps at the top of the ranking, both in an eco-centric and anthropocentric vision. Not the same if we consider the whole ranking of the other sites, which differs quite substantially. All this shows the suitability of the AHP method and the software implemented in responding to the general socio-political context for choosing the most relevant site for a public work such as an airport.
Integer Programming Formulations for Maximum Lifetime Broadcasting Problems in Wireless Sensor Networks  [PDF]
Roberto Montemanni
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.212111
Abstract: Approaches based on integer linear programming have been recently proposed for topology optimization in wireless sensor networks. They are, however, based on over-theoretical, unrealistic models. Our aim is to show that it is possible to accommodate realistic models for energy consumption and communication protocols into integer linear programming. We analyze the maximum lifetime broadcasting topology problem and we present realistic models that are also shown to provide efficient and practical solving tools. We present a strategy to substantially speed up the convergence of the solving process of our algorithm. This strategy introduces a practical drawback, however, in the characteristics of the optimal solutions retrieved. A method to overcome this drawback is discussed. Computational experiments are reported.
Innovation in the Financial Sector: Persistence and Schumpeterian Hypotheses  [PDF]
Roberto Napoli
Journal of Service Science and Management (JSSM) , 2008, DOI: 10.4236/jssm.2008.13023
Abstract: The paper analyses innovation features in the German financial sector. The first topic is persistence of innovation. Our research question is: Do innovators plan further innovation for the subsequent year? In addition, since the sector is so far poorly researched, very basic questions are investigated in the paper: the relationship between firm size and innovation (both linear and quadratic), as well as the impact of market structure on innovation (i.e. Schumpeterian and neo-Schumpeterian hypotheses). Finally, Suttons argument of R & D sunk costs is investigated as a possible explanation for persistence. Basing on the CIS IV survey, our empirical evidence is consistent with the results of similar researches carried out in different sectors.
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