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1.
Alessandri M Beretta GL Ferretti E Mancia A Khobta A Capranico G 《Journal of molecular biology》2004,337(2):295-305
Human topoisomerase I-B (Top1) efficiently relaxes DNA supercoils during basic cellular processes, and can be transformed into a DNA-damaging agent by antitumour drugs, enzyme mutations and DNA lesions. Here, we describe Gal4-Top1 chimeric proteins (GalTop) with an N-terminal truncation of Top1, and mutations of the Gal4 Zn-cluster and/or Top1 domains that impair their respective DNA-binding activities. Expression levels of chimeras were similar in yeast cells, however, GalTop conferred an increased CPT sensitivity to RAD52- yeast cells as compared to a GalTop with mutations of the Gal4 domain, showing that a functional Gal4 domain can alter in vivo functions of Top1. In vitro enzyme activity was tested with a DNA relaxation assay using negatively supercoiled plasmids with 0 to 5 Gal4 consensus motifs. Only GalTop with a functional Gal4 domain could direct DNA relaxation activity of Top1 specifically to DNA molecules containing Gal4 motifs. By using a substrate competition assay, we could demonstrate that the Gal4-anchored Top1 remains functional and efficiently relax DNA substrates in cis. The enhanced CPT sensitivity of GalTop in yeast cells may then be due to alterations of the chromatin-binding activity of Top1. The GalTop chimeras may indeed mimic a normal mechanism by which Top1 is recruited to chromatin sites in living cells. Such hybrid Top1s may be helpful in further dissecting enzyme functions, and constitute a prototype of a site-specific DNA cutter endowed with high cell lethality. 相似文献
2.
Ferruccio Guerrieri Martin Kalous Edmondo Adorisio Nicola Turturro Zdenek Drahota Palmiro Cantatore Giuseppe Santoro 《Journal of bioenergetics and biomembranes》1998,30(3):269-276
In liver mitochondria isolated from hypothyroid rats, the rate of ATP synthesis is lower than in mitochondria from normal rats. Oligomycin-sensitive ATP hydrolase activity and passive proton permeability were significantly lower in submitochondrial particles from hypothyroid rats compared to those isolated from normal rats. In mitochondria from hypothyroid rats, the changes in catalytic activities of F0F1-ATP synthase are accompanied by a decrease in the amount of immunodetected -F1, F01-PVP, and OSCP subunits of the complex. Northern blot hybridization shows a decrease in the relative cytosolic content of mRNA for -F1 subunit in liver of hypothyroid rats. Administration of 3,5,3-triodo-L-thyronine to the hypothyroid rats tends to remedy the functional and structural defects of F0F1-ATP synthase observed in the hypothyroid rats. The results obtained indicate that hypothyroidism leads to a decreased expression of F0F1-ATP synthase complex in liver mitochondria and this contributes to the decrease of the efficiency of oxidative phosphorylation. 相似文献
3.
The effect of the sinking rate, or rate of medium flow (φ) on the rate of phosphate incorporation (V) by the planktonic diatoms Thalassiosira fluviatilis Hust. and T. pseudonana Hasle & Heimdal in batch and chemostat cultures was determined by passing medium at defined flow rates (0.5–25.0 mm·min?1) over algae on membrane filters. At concentrations from 1 to 100 μg phosphorus·l?1 V, increases with increasing velocity of flow, approaching a maximum value (Vm) as described by the empirical relationship: where Kφ is the sinking rate value when V = 1/2 Vm+ Vo and Vo is the uptake at 0 rate of flow. By comparing uptake at controlled flow with uptake in a vigorously stirred medium, the phosphate concentration in the cell boundary layer can be determined. The sinking rate that reduces the phosphate concentration in the boundary layer to half of nominal concentration in the medium is much lower for the larger T. fluviatilis than for T. pseudonana. For both diatoms, it is inversely related to the nominal concentration. 相似文献
4.
Edmondo Honsell 《Plant biosystems》2013,147(1-2):89-97
Abstract OBSERVATIONS ON THE RELATION BETWEEN PROTOPLASMIC ACCUMULATION OF THE FLUOROCHROME URANIN AND RESPIRATORY INTENSITY IN OSCILLATORIA IRRIGUA Kütz. — Uranin (sodic fluorescein) is a vital dye of peculiar cytophysiological interest, since it is accumulated chiefly in the nucleus, cytoplasm and chondriosomes of living plants cell. The degree of accumulation of this dye is in evident relation with the cellular activity. In the present paper the relation between respiration and secundary fluorescence induced by uranin in the cells of Oscillatoria irrigua is demonstrated. The A. has also observed that a reduction of the respiratory activity of so coloured cells through inhibitory substances as f. i. oxyquinoline results in a releasing of uranin from the cell. In this case the dye is no more detained in the cells and flows outwards. The true nature of the accumulation of uranin and its relations with the cellular activity are not yet clear, but its value as research mean to appreciate the cellular activity of organisms is emphasized. 相似文献
5.
Simone Colombero Edmondo Bonelli Tassos Kotsakis Giulio Pavia Marco Pavia Giorgio Carnevale 《Geobios》2013,46(1-2):111-125
The stratigraphic and paleoenvironmental context of the Verduno fossil vertebrate locality is discussed herein based on its rodent record. The Verduno section crops out in the southern part of the Tertiary Piedmont Basin (TPB), and can be included in the Messinian post-evaporitic Cassano Spinola Fm., chronologically corresponding to the so-called Lago-Mare event. Rodents are represented by a relatively rich assemblage. Murids are by far the most diverse and abundant, with at least four taxa, including the common Centralomys benericettii and Paraethomys meini, and the rare Apodemus gudrunae and Occitanomys sp. Cricetids are represented by a single species, Apocricetus cf. A. barrierei. Muscardinus aff. M. vireti appears to be the only glirid present at Verduno. The Verduno rodent assemblage shares some taxa with other Messinian post-evaporitic localities from Italy bearing continental vertebrate remains, such as Brisighella (central Italy) and Moncucco Torinese (NW Italy) (e.g., C. benericettii, P. meini) and, possibly, with Ciabòt Cagna (NW Italy). However, the general structure of these four Messinian assemblages displays substantial differences, which may reflect different palaeoenvironmental conditions. 相似文献
6.
Falleti E Fabris C Toniutto P Fontanini E Cussigh A Bitetto D Fornasiere E Avellini C Minisini R Pirisi M 《Cytokine》2008,44(2):256-261
This study aimed to verify whether specific single nucleotide polymorphisms (SNPs) of the transforming growth factor-beta1 (TGF-beta1) may predispose to end-stage liver disease and/or hepatocellular carcinoma (HCC). One hundred eighty-eight consecutive patients transplanted for liver cirrhosis (HBV N=21, HCV N=68, alcoholic N=55 and others N=23) and a control group of 140 healthy blood donors were investigated. Four SNPs were studied by restriction fragment length assays: -800G>A, -509C>T, Leu10Pro and Arg25Pro. Patients were found to possess the -509T/ * (TT 53/188, CT 85/188, CC 50/188 vs TT 22/140, CT 61/140, CC 57/140; p<0.002) and Arg25Pro C/ * genotypes (CC 1/188, CG 31/188, GG 156/188 vs CC 0/140, CG 13/140, GG 127/140; p<0.05) more frequently than controls. Patients with cirrhosis complicated by HCC possessed more frequently the Leu10Pro T/ * genotype than patients without HCC (TT 20/54, CT 26/54, CC 8/54 vs TT 31/134, CT 69/134, CC 34/134; p<0.05). The analysis of molecular variance detected significant genotypic differentiations between controls and cirrhotics but not between cirrhotics with or without HCC. In conclusion, TGF-beta1 SNPs probably facilitate the development of liver cirrhosis, while they seem to have a limited role in predicting the occurrence of HCC. 相似文献
7.
Francesco Berti Edmondo Campisi Chiara Toniolo Laura Morelli Stefano Crotti Roberto Rosini Maria Rosaria Romano Vittoria Pinto Barbara Brogioni Giulia Torricelli Robert Janulczyk Guido Grandi Immaculada Margarit 《The Journal of biological chemistry》2014,289(34):23437-23448
The Group B Streptococcus capsular polysaccharide type IX was isolated and purified, and the structure of its repeating unit was determined. Type IX capsule →4)[NeupNAc-α-(2→3)-Galp-β-(1→4)-GlcpNAc-β-(1→6)]-β-GlcpNAc-(1→4)-β-Galp-(1→4)-β-Glcp-(1→ appears most similar to types VII and V, although it contains two GlcpNAc residues. Genetic analysis identified differences in cpsM, cpsO, and cpsI gene sequences as responsible for the differentiation between the three capsular polysaccharide types, leading us to hypothesize that type V emerged from a recombination event in a type IX background. 相似文献
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9.
Cussigh A Falleti E Fabris C Bitetto D Cmet S Fontanini E Bignulin S Fornasiere E Fumolo E Minisini R Pirisi M Toniutto P 《Immunogenetics》2011,63(1):33-41
Host genetic variation may affect the outcome of chronic viral hepatitides, favoring viral clearance and/or modulating the inflammatory response to persistent infection. Our aims were to assess whether interleukin 6 (IL-6) promoter polymorphisms are associated with chronic hepatitis C virus (HCV) infection and to clarify the role of IL-6 haplotypes in facilitating progressive disease. The study included 424 Italian patients (233 males, median age 53 years) affected by HCV chronic infection. IL6 -1363, -597, -572, -174, and +2954 polymorphic loci were assayed by means of restriction fragment length polymorphism. Three hundred forty-four healthy Italian blood donors (245 males, median age 50 years) served as controls. Comparing patients and controls analysis of molecular variance was highly significant (p?0.0001); at a locus by locus approach, the frequencies of minor alleles in the -1363 (p?0.02), -597 (p?0.02), and -174 (p?0.01) polymorphisms were confirmed to be less represented in patients than in controls. Carrying the wild-type G allele at the -597 and -174 loci identified an unfavorable haplotype; carrying the minor allele in one/both loci identified an indifferent/favorable haplotype. Male patients carrying two unfavorable haplotypes had the highest adjusted mean?±?standard error Ishak staging score (3.56?±?0.19), while females carrying one or no unfavorable haplotypes had the lowest (2.69?±?0.21); the remaining patients had an intermediate value (3.12?±?0.13, p?0.01). In conclusion, IL-6 promoter polymorphisms influence the development of chronic HCV infection. With the permissive effect of male gender, haplotypes represented by the wild-type allele for -597 and -174 loci appear to favor a worse evolution of the disease. 相似文献
10.
Falleti E Cmet S Fabris C Bitetto D Cussigh A Fornasiere E Bignulin E Feruglio C Mosanghini E Fontanini E Pirisi M Toniutto P 《Cytokine》2012,57(1):68-73