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31.
Rossetti L Franceschin M Schirripa S Bianco A Ortaggi G Savino M 《Bioorganic & medicinal chemistry letters》2005,15(2):413-420
While the importance of the aromatic core in small organic molecules, studied as G-quadruplex mediated telomerase inhibitors, appears well studied by a number of researches, the role of side chains has been less well characterized. In this paper, we have studied the ability of six perylene derivatives with different side chains to induce both inter- and intramolecular G-quadruplex structures. The distance between the aromatic core and the positive charges in the side chains emerges as a significant molecular feature in G-quadruplex formation. Furthermore, the G-quadruplex formation appears also related to drugs 'self-association', influenced by the side chains basicity. The different efficiencies of the six perylene derivatives in interacting both with inter- and intramolecular G-quadruplex structures satisfactorily correlate with telomerase inhibition in cell-free systems. 相似文献
32.
Telomeric chromatin has different features with respect to bulk chromatin, since nucleosomal repeat along the chain is unusually short. We studied the role of telomeric DNA sequences on nucleosomal spacing in a model system. Nucleosomal arrays, assembled on a 1500-bp-long human telomeric DNA and on a DNA fragment containing 8 copies of the 601 strong nucleosome positioning sequence, have been studied at the single molecule level, by atomic force microscopy imaging. Random nucleosome positioning was found in the case of human telomeric DNA. On the contrary, nucleosome positioning on 601 DNA is characterized by preferential positions of nucleosome dyad axis each 200 bp. The AFM-derived nucleosome organization is in satisfactory agreement with that predicted by theoretical modeling, based on sequence-dependent DNA curvature and flexibility. The reported results show that DNA sequence has a main role, not only in mononucleosome thermodynamic stability, but also in the organization of nucleosomal arrays. 相似文献
33.
MJ Savino LA Sánchez FM Saguir MC de Nadra 《World journal of microbiology & biotechnology》2012,28(3):1003-1012
We investigated the potentiality of lactic acid bacteria (LAB) isolated from two apples variety to utilize arginine at different
initial pH values. Apples surface contained average levels of bacteria ranging from log 2.49 ± 0.53 to log 3.73 ± 0.48 cfu/ml
for Red Delicious and Golden Delicious varieties, respectively. Thirty-one strains able to develop in presence of arginine
at low pH were phenotypically and genotipically identified as belonging to Lactobacillus, Pediococcus and Leuconostoc genera. In general, they did not produce ammonia from arginine when cultivated in basal medium with arginine (BMA) at pH
4.5 or 5.2. When this metabolite was quantified only six strains belonging to Leuconostoc dextranicum, Lactobacillus brevis and Lactobacillus plantarum species formed higher ammonia amounts in BMA as compared to control. This was correlated with arginine utilization and it
was more pronounced at pH 4.5 than 5.2. Analysis of citrulline production confirmed the arginine utilization in these bacteria
by the arginine deiminase (ADI) pathway. Maxima citrulline production was observed for Lactobacillus brevis M15 at the two pH values. In this strain ammonia was formed at higher rate than citrulline, which was detected in concentration
lower than 1 mM. Thus, main LAB species found on apple surfaces with abilities to degrade arginine by the ADI pathway under
different conditions were reported here at the first time. The results suggested that the ADI pathway in apples LAB might
not be mainly relevant for their survival in the acid natural environmental, despite leading to the ammonia formation, which
may contribute to the increase in pH, coping the acid stress. 相似文献
34.
35.
Thymic involution is a slow physiological process than can be accelerated by some pathological or experimental conditions. In this work we kept male mice under low temperatures in order to observe whether or not thymic involution would be promoted. For this purpose, we carried out a histometrical analysis of the thymus and observed that there was a decrease in both cortical and medullary regions of the thymic lobules. These changes paralleled a loss in the absolute and relative weights of the thymus. It was concluded that low temperatures induce thymic involution even in nonhibernating animals. 相似文献
36.
D. Dimou A.M. D'Onghia M. Laimer da Camara Machado V. Savino 《Journal of Phytopathology》1994,142(4):258-262
A virus recovered by inoculation of sap from Austrian vines with yellow mosaic symptoms was compared with, and found virtually indistinguishable from, an authentic Hungarian isolate of grapevine chrome mosaic nepovirus. This seems to be the first record of the virus in Austria. 相似文献
37.
38.
The occurrence of coprophilous fungi on samples of antelope, buffalo, zebra and hippopotamus dung collected from the Marula
Estates in Kenya was recorded. A hundred and seventy three fungal isolates representative of 40 genera and 59 species were
identified. Among these species, 23 were Ascomycetes (39%), 30 Deuteromycetes (50.8%), 5 Zygomycetes (8.5%) and 1 Basidiomycete
(1.7%). Ascobolus immersus, Coprotus niveus, Iodophanus carneus, Lasiobolus lasioboloides, Podospora anserina, P. australis
and Sporormiella minima were the dominant species occurring in the dung of these animals. Notes on infrequent or interesting
Ascomycetes include Kernia nitida, Saccobolus versicolor, Sordaria fimicola and others. The interdependence of the vegetation
of this area with the fungi occurring on the dung of these animals is discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
39.
Maria Scarselli Laura Santini Sara Dragonetti Silvana Savino Maurizio Comanducci Giacomo Romagnoli Lucia Banci Rino Rappuoli 《Journal of molecular biology》2009,386(1):97-41775
The factor H binding protein (fHbp) is a 27-kDa membrane-anchored lipoprotein of Neisseria meningitidis that allows the survival of the bacterium in human plasma; it is also a major component of a universal vaccine against meningococcus B.In this study, we used nuclear magnetic resonance spectroscopy, mutagenesis, and in silico modeling to map the epitope recognized by MAb502, a bactericidal monoclonal antibody elicited by fHbp. The data show that the antibody recognizes a conformational epitope within a well-defined area of the immunodominant C-terminal domain of the protein that is formed by two loops connecting different β-strands of a β-barrel and a short α-helix brought in spatial proximity by the protein folding. The identification of the protective epitopes of fHbp is an important factor for understanding the mechanism(s) of an effective immune response and provides valuable guidelines for designing variants of the protein able to induce broadly protective immunity. 相似文献
40.