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71.
Perandin F Manca N Piccolo G Calderaro A Galati L Ricci L Medici MC Arcangeletti C Dettori G Chezzi C 《The new microbiologica》2003,26(1):91-100
The species-specific nested-PCR previously described by Snounou and others for detecting the four parasite species that cause human malaria is evaluated in the current study testing 230 blood samples. The results are compared with those obtained by microscopy and, for 101 samples out of 230, with those previously obtained by a genus-specific PCR based method (pg-PCR) followed by species-specific Southern-blot hybridization. All blood specimens were obtained from patients (127 foreigners and 103 Italians) with a suspect clinical diagnosis of imported malaria in Italy: 76 were positive by microscopy and 83 were positive by nested-PCR. The last method also revealed 10 double infections (8 foreigners and 2 Italians) which were not identified by microscopy or by pg-PCR with species-specific Southern-blot hybridization. Fifty-four out of 83 positive samples tested by nested-PCR were submitted to genomic sequence analysis, which confirmed the presence of DNA region portion encoding the 18S rRNA corresponding to the Plasmodium species identified by nested-PCR. These results demonstrate that the nested-PCR assay surpasses microscopy and pg-PCR with species-specific Southern-blot hybridization, both in sensitivity and in diagnostic accuracy. Moreover, it is quicker because it requires no further blotting or hybridization of PCR amplification products. This method also offers a clear advantage in the detection of mixed infections, which is important not only for successful medical treatment but also for the study of malaria epidemiology. Finally, our study also highlights the value of genomic sequence analysis for validating PCR results. 相似文献
72.
73.
Ada Ricci Angela Carra Enrico Rolli Cristina Bertoletti Camillo Branca 《Plant Growth Regulation》2003,40(3):207-212
Stem slices cut from micropropagated cuttings of apple rootstock M26 were cultured in the presence of indole-3-butyric acid (IBA) plus N,N-bis-(2,3-methylenedioxyphenyl)urea or N,N-bis-(3,4-methylenedioxyphenyl)urea, to verify if there was an interaction between them in enhancing root formation. The N,N-bis-(methylenedioxyphenyl)ureas were supplemented after, before and in the simultaneous presence of auxin. Our data demonstrate that only the simultaneous presence of auxin and N,N-bis-(methylenedioxyphenyl)ureas in the culture medium enhanced root formation on M26 stem slices. The percentage of rooted slices obtained in the presence of the mixtures was significantly different from that obtained in the presence of low auxin concentration alone (1µM). Moreover both the percentage of rooted slices and the number of roots per slice obtained in these culture conditions was not significantly different to that of the optimal auxinic treatment in which the auxin concentration was threefold higher. 相似文献
74.
The terminal organelle of the cell wall-less pathogenic bacterium Mycoplasma pneumoniae is a complex structure involved in adherence, gliding motility and cell division. This membrane-bound extension of the mycoplasma cell possesses a characteristic electron-dense core. A number of proteins having direct or indirect roles in M. pneumoniae cytadherence have been previously localized to the terminal organelle. However, the cytadherence-accessory protein HMW2, which is required for the stabilization of several terminal organelle components, has been refractory to antibody-based approaches to subcellular localization. In the current study, we constructed a sandwich fusion of HMW2 and enhanced green fluorescent protein (EGFP) and expressed this fusion in wild-type M. pneumoniae and the hmw2- mutant I-2. The fusion protein was produced in both backgrounds at wild-type levels and supported stabilization of proteins HMW1, HMW3 and P65, and haemadsorption function in mutant I-2. Furthermore, the fusion protein was fluorescent and localized specifically to the terminal organelle. However, the EGFP moiety appeared to interfere partially with processes related to cell division, as transformant cells exhibited an increased incidence of bifurcated attachment organelles. These data together with structural predictions suggest that HMW2 is the defining component of the electron-dense core of the terminal organelle. 相似文献
75.
Scharfe C Zaccaria P Hoertnagel K Jaksch M Klopstock T Dembowski M Lill R Prokisch H Gerbitz KD Neupert W Mewes HW Meitinger T 《Nucleic acids research》2000,28(1):155-158
MITOP (http://www.mips.biochem.mpg.de/proj/medgen/mitop/) is a comprehensive database for genetic and functional information on both nuclear- and mitochondrial-encoded proteins and their genes. The five species files--Saccharomyces cerevisiae, Mus musculus, Caenorhabditis elegans, Neurospora crassa and Homo sapiens--include annotated data derived from a variety of online resources and the literature. A wide spectrum of search facilities is given in the overlapping sections 'Gene catalogues', 'Protein catalogues', 'Homologies', 'Pathways and metabolism' and 'Human disease catalogue' including extensive references and hyperlinks to other databases. Central features are the results of various homology searches, which should facilitate the investigations into interspecies relationships. Precomputed FASTA searches using all the MITOP yeast protein entries and a list of the best human EST hits with graphical cluster alignments related to the yeast reference sequence are presented. The orthologue tables with cross-listings to all the protein entries for each species in MITOP have been expanded by adding the genomes of Rickettsia prowazeckii and Escherichia coli. To find new mitochondrial proteins the complete yeast genome has been analyzed using the MITOPROT program which identifies mitochondrial targeting sequences. The 'Human disease catalogue' contains tables with a total of 110 human diseases related to mitochondrial protein abnormalities, sorted by clinical criteria and age of onset. MITOP should contribute to the systematic genetic characterization of the mitochondrial proteome in relation to human disease. 相似文献
76.
Diaz Ricci JC 《Biochemical and biophysical research communications》2000,271(1):244-249
A mathematical model that includes biochemical interactions among the PTS system, phosphofructokinase (PFK), and pyruvate kinase (PK) is used to evaluate the dynamic behavior of the glycolytic pathway of Escherichia coli under steady-state conditions. The influence of ADP, phosphoenolpyruvate (PEP), and fructose-6-phosphate (F6P) on the dynamic regulation of this pathway is also analyzed. The model shows that the dynamic behavior of the system is affected significantly depending on whether ADP, PEP, or F6P is considered constant a steady state. Sustained oscillations are observed only when dADP/dt not equal 0 and completely suppressed if dADP/dt = 0 at any steady-state value. However, when PEP or F6P is constant, the system evolves toward the formation of stable limit cycles with periods ranging from 0.2 min to hours. 相似文献
77.
Micaloni C Mazzetti AP Nuccetelli M Rossjohn J McKinstry WJ Antonini G Caccuri AM Oakley AJ Federici G Ricci G Parker MW Lo Bello M 《Biochemistry》2000,39(51):15961-15970
We have probed the electrophilic binding site (H-site) of human glutathione transferase P1-1 through mutagenesis of two valines, Val 10 and Val 35, into glycine and alanine, respectively. These two residues were previously shown to be the only conformationally variable residues in the H-site and hence may play important roles in cosubstrate recognition and/or product dissociation. Both of these mutant enzymes have been expressed in Escherichia coli and purified and their kinetic properties characterized. The results demonstrate that Val35Ala behaves similarly to wild-type, whereas Val10Gly exhibits a strong decrease of k(cat) and k(cat)/K(m) (cosub) toward two selected cosubstrates: ethacrynic acid and 1-chloro-2,4-dinitrobenzene. Pre-steady-state kinetic analysis of the GSH conjugation with ethacrynic acid shows that both wild-type and Val10Gly mutant enzymes exhibit the same rate-limiting step: the dissociation of product. However, in the Val10Gly mutant there is an increased energetic barrier which renders the dissociation of product more difficult. Similar results are found for the Val10Gly mutant with 1-chloro-2,4-dinitrobenzene as cosubstrate. With this latter cosubstrate, Val 10 also exerts a positive role in the conformational transitions of the ternary complex before the chemical event. Crystallographic analysis of the Val10Gly mutant in complex with the inhibitor S-hexyl-GSH suggests that Val 10 optimally orientates products, thus promoting their exit from the active site. 相似文献
78.
Palli SR Ladd TR Ricci AR Primavera M Mungrue IN Pang AS Retnakaran A 《Journal of insect physiology》1998,44(5-6):509-524
Spruce budworm larvae produce large quantities of two proteins (Choristoneura fumiferana diapause associated proteins 1 and 2, CfDAP1 and CfDAP2) that are diapause related. These proteins appeared soon after hatching and increased in abundance, reaching maximum levels by four days into the 1st instar, and they remained at high levels until three days after the termination of diapause. These two proteins were purified to homogeneity and their NH2-terminal sequences were obtained. Oligonucleotide primers designed on the basis of these NH2-terminal sequences were used in RT-PCR to isolate the cDNA fragments coding for these proteins. These PCR fragments were then used as probes to isolate the cDNAs that contained the complete coding region. The 2.5kb mRNAs coding for these proteins started to appear 24hr after hatching and large quantities of these mRNAs were detected in 1st instar and 2nd instar larvae until the 2nd instar larvae entered diapause. Low levels of these mRNAs were detected in the 2nd instar larvae that were preparing to enter diapause, in those that were in diapause as well as in those that terminated diapause. Low levels of CfDAP1 mRNA were also detected on days 1 and 2 after ecdysis to the 3rd instar. However, no CfDAP1 and CfDAP2 mRNAs could be detected during the 4th and 5th instar larval stages. The mRNAs reappeared 24hr after the 5th instar larvae molted into the 6th instar and increased to reach maximum levels by 60hr after ecdysis. The mRNA levels remained high until 156hr after ecdysis into the 6th instar (36-48hr before pupal ecdysis), after which they disappeared once again. Immunocytochemical analyses showed that CfDAP1 protein was present in 2nd and 6th instar larval fat body but not in 5th instar larval fat body. Thus, the same two genes were expressed for the first time before C. fumiferana larvae entered diapause and for a 2nd time before pupation. 相似文献
79.
Comparison of Binding Properties and Early Biological Effects of
Elicitins in Tobacco Cells 总被引:7,自引:0,他引:7
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Stéphane Bourque Michel Ponchet Marie-No?lle Binet Pierre Ricci Alain Pugin Angela Lebrun-Garcia 《Plant physiology》1998,118(4):1317-1326
Elicitins are a family of small proteins secreted by Phytophthora species that have a high degree of homology and elicit defense reactions in tobacco (Nicotiana tabacum). They display acidic or basic characteristics, the acidic elicitins being less efficient in inducing plant necrosis. In this study we compared the binding properties of four elicitins (two basic and two acidic) and early-induced signal transduction events (Ca2+ influx, extracellular medium alkalinization, and active oxygen species production). The affinity for tobacco plasma membrane-binding sites and the number of binding sites were similar for all four elicitins. Furthermore, elicitins compete with one another for binding sites, suggesting that they interact with the same receptor. The four elicitins induced Ca2+ influx, extracellular medium alkalinization, and the production of active oxygen species in tobacco cell suspensions, but the intensity and kinetics of these effects were different from one elicitin to another. As a general observation the concentrations that induce similar levels of biological activities were lower for basic elicitins (with the exception of cinnamomin-induced Ca2+ uptake). The qualitative similarity of early events induced by elicitins indicates a common transduction scheme, whereas fine signal transduction tuning is different in each elicitin. 相似文献
80.
Simone Lanini Alessandro Nanni Costa Vincenzo Puro Francesco Procaccio Paolo Antonio Grossi Francesca Vespasiano Andrea Ricci Sergio Vesconi Michael G. Ison Yehuda Carmeli Giuseppe Ippolito Donor-Recipient Infection Collaborative Study Group 《PloS one》2015,10(4)