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251.
252.
Simone Fausti Giovanni La Penna Carla Cuniberti Angelo Perico 《Molecular simulation》2013,39(4-6):307-324
Abstract The local dynamics of macromolecules is obtained to second-order in the mode-coupling expansion of the Smoluchowski diffusion theory. The NMR spin-lattice relaxation times of different 13C or 15N nuclei along the chains are calculated and compared to experimental data from the literature. The macromolecules are considered as fluctuating 3D structures undergoing rotational diffusion. The fluctuations can be evaluated with any technique for sampling the configurational space. In the presented test cases Molecular Dynamics simulations have been applied to a DNA fragment and to the NK-2 homeodomain. In the case of the double-stranded DNA fragment d(TpCpGpCpG)2, second and even first order theories are found to be in close agreement with experimental results. The major advantage of the diffusion technique is that only a good statistics is important as input while the solvent dynamic effects enter through hydrodynamic theory. Application based on Hybrid Monte Carlo schemes coupled with J-walking, are now in progress. 相似文献
253.
Leverrier S Bergamaschi D Ghali L Ola A Warnes G Akgül B Blight K García-Escudero R Penna A Eddaoudi A Storey A 《Apoptosis : an international journal on programmed cell death》2007,12(3):549-560
Apoptotic elimination of UV-damaged cells from the epidermis is an important step in preventing both the emergence and expansion
of cells with carcinogenic potential. A pivotal event in apoptosis is the release of apoptogenic factors from the mitochondria,
although the mechanisms by which the different proteins are released are not fully understood. Here we demonstrate that UV
radiation induced the mitochondrial to nuclear translocation of apoptosis inducing factor (AIF) in normal skin. The human
papillomavirus (HPV) E6 protein prevented release of AIF and other apoptotic factors such as cytochrome c and Omi from mitochondria of UV-damaged primary epidermal keratinocytes and preserved mitochondrial integrity. shRNA silencing
of Bak, a target for E6-mediated proteolysis, demonstrated the requirement of Bak for UV-induced AIF release and mitochondrial
fragmentation. Furthermore, screening non-melanoma skin cancer biopsies revealed an inverse correlation between HPV status
and AIF nuclear translocation. Our results indicate that the E6 activity towards Bak is a key factor that promotes survival
of HPV-infected cells that facilitates tumor development. 相似文献
254.
Julia Penna Coutinho Anna Caroline Campos Aguiar Pierre Alexandre dos Santos Joaquim Corsino Lima Maria Gabrielle Lima Rocha Carlos Leomar Zani Tania Maria Almeida Alves Ant?nio Euzébio Goulart Santana Maria de Meneses Pereira Antoniana Ursine Krettli 《Memórias do Instituto Oswaldo Cruz》2013,108(8):974-982
Infusions of Aspidosperma nitidum (Apocynaceae) wood bark are usedto treat fever and malaria in the Amazon Region. Several species of this family areknown to possess indole alkaloids and other classes of secondary metabolites, whereasterpenoids, an inositol and the indole alkaloids harmane-3 acid and braznitiduminehave been described in A. nitidum . In the present study, extractsfrom the wood bark, leaves and branches of this species were prepared for assaysagainst malaria parasites and cytotoxicity testing using human hepatoma and normalmonkey kidney cells. The wood bark extracts were active against Plasmodiumfalciparum and showed a low cytotoxicity in vitro, whereas the leaf andbranch extracts and the pure alkaloid braznitidumine were inactive. A crude methanolextract was subjected to acid-base fractionation aimed at obtaining alkaloid-richfractions, which were active at low concentrations against P.falciparum and in mice infected with and sensitive Plasmodiumberghei parasites. Our data validate the antimalarial usefulness ofA. nitidum wood bark, a remedy that can most likely help tocontrol malaria. However, the molecules responsible for this antimalarial activityhave not yet been identified. Considering their high selectivity index, thealkaloid-rich fractions from the plant bark might be useful in the development of newantimalarials. 相似文献
255.
Mireille ?ngela Bernardes Sousa Edilberto Nogueira Mendes Guilherme Birchal Collares Luciano Amedée Péret-Filho Francisco José Penna Paula Prazeres Magalh?es 《Memórias do Instituto Oswaldo Cruz》2013,108(1):30-35
Diarrhoeal disease is still considered a major cause of morbidity and mortality among children. Among diarrhoeagenic agents, Shigella should be highlighted due to its prevalence and the severity of the associated disease. Here, we assessed Shigella prevalence, drug susceptibility and virulence factors. Faeces from 157 children with diarrhoea who sought treatment at the Children''s Hospital João Paulo II, a reference children´s hospital in Belo Horizonte, state of Minas Gerais, Brazil, were cultured and drug susceptibility of the Shigella isolates was determined by the disk diffusion technique. Shigella virulence markers were identified by polymerase chain reaction. The bacterium was recovered from 10.8% of the children (88.2% Shigella sonnei). The ipaH, iuc, sen and ial genes were detected in strains isolated from all shigellosis patients; set1A was only detected in Shigella flexneri. Additionally, patients were infected by Shigella strains of different ial, sat, sen and set1A genotypes. Compared to previous studies, we observed a marked shift in the distribution of species from S. flexneri to S. sonnei and high rates of trimethoprim/sulfamethoxazole resistance. 相似文献
256.
Rhodnius prolixus LIPOPHORIN: LIPID COMPOSITION AND EFFECT OF HIGH TEMPERATURE ON PHYSIOLOGICAL ROLE
David Majerowicz Milton P. Cezimbra Michele Alves‐Bezerra Petter F. Entringer Georgia C. Atella Mauro Sola‐Penna José R. Meyer‐Fernandes Katia C. Gondim 《Archives of insect biochemistry and physiology》2013,82(3):129-140
Lipophorin is a major lipoprotein that transports lipids in insects. In Rhodnius prolixus, it transports lipids from midgut and fat body to the oocytes. Analysis by thin‐layer chromatography and densitometry identified the major lipid classes present in the lipoprotein as diacylglycerol, hydrocarbons, cholesterol, and phospholipids (PLs), mainly phosphatidylethanolamine and phosphatidylcholine. The effect of preincubation at elevated temperatures on lipophorin capacity to deliver or receive lipids was studied. Transfer of PLs to the ovaries was only inhibited after preincubation of lipophorin at temperatures higher than 55°C. When it was pretreated at 75°C, maximal inhibition of phospholipid transfer was observed after 3‐min heating and no difference was observed after longer times, up to 60 min. The same activity was also obtained when lipophorin was heated for 20 min at 75°C at protein concentrations from 0.2 to 10 mg/ml. After preincubation at 55°C, the same rate of lipophorin loading with PLs at the fat body was still present, and 30% of the activity was observed at 75°C. The effect of temperature on lipophorin was also analyzed by turbidity and intrinsic fluorescence determinations. Turbidity of a lipophorin solution started to increase after preincubations at temperatures higher than 65°C. Emission fluorescence spectra were obtained for lipophorin, and the spectral area decreased after preincubations at 85°C or above. These data indicated no difference in the spectral center of mass at any tested temperature. Altogether, these results demonstrate that lipophorin from R. prolixus is very resistant to high temperatures. 相似文献
257.
Cutting edge: differential chemokine production by myeloid and plasmacytoid dendritic cells 总被引:10,自引:0,他引:10
Penna G Vulcano M Roncari A Facchetti F Sozzani S Adorini L 《Journal of immunology (Baltimore, Md. : 1950)》2002,169(12):6673-6676
To examine the different roles of myeloid dendritic cells (M-DCs) and plasmacytoid dendritic cells (P-DCs) in the induction and regulation of immune response, we have studied chemokine secretion by freshly isolated DC subsets in response to bacterial, viral, and T cell-derived stimuli. M-DCs selectively produced very high levels of the homeostatic chemokines CC chemokine ligand (CCL)17 and CCL22, while P-DCs produced very little if any. In contrast, the proinflammatory chemokine CCL3 was secreted mostly by P-DCs, whereas CCL4 and CXC chemokine ligand 8 were produced by both subsets. The selective production of CCL17 and CCL22 by M-DCs but not P-DCs was confirmed in vivo by immunohistology on human reactive lymph node sections. The high production of CCR4 ligands by M-DCs suggests their capacity to selectively recruit at sites of inflammation T cells with regulatory properties or with a Th2 phenotype, whereas P-DCs, by preferentially secreting CCR1/CCR5 ligands, would mostly recruit effector T cells and, in particular, Th1-type cells. 相似文献
258.
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260.
Fabio Penna Fabrizio Pin Domiziana Costamagna Patrizia Reffo Francesco Maria Baccino Gabriella Bonelli Paola Costelli 《PloS one》2012,7(9)
Differently from the antiapoptotic action most commonly assigned to peroxisome proliferators (PPs), we demonstrated that some of them, clofibrate (CF) in particular, display clearcut apoptogenic properties on rat hepatoma cell lines. We and others could confirm that CF as well as various other PPs can induce apoptosis in a variety of cells, including human liver, breast and lung cancer cell lines. The present study was aimed at investigating the cytotoxic action of CF on a neoplastic line of different origin, the human T leukemia Jurkat cells. We observed that CF rapidly triggers an extensive and morphologically typical apoptotic process on Jurkat cells, though not in primary T cells, which is completely prevented by the polycaspase inhibitor zVADfmk. Gene silencing studies demonstrated that CF-induced apoptosis in Jurkat cells is partially dependent on activation of caspase 2. Looking for a possible trigger of caspase 2 activation, we observed increased levels of phosphorylated eIF2α and JNK in CF-treated cells. Moreover, intracellular Ca2+ homeostasis was perturbed. Together, these findings are suggestive for the occurrence of ER stress, an event that is known to have the potential to activate caspase 2. The present observations demonstrate that CF induces in Jurkat cells a very fast and extensive apoptosis, that involves induction of ER stress and activation of caspases 2 and 3. Since apoptosis in Jurkat cells occurs at pharmacologically relevant concentrations of CF, the present findings encourage further in depth analysis in order to work out the potential implications of CF cytotoxcity on leukemic cells. 相似文献