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11.
12.
Sumpter B Dunham R Gordon S Engram J Hennessy M Kinter A Paiardini M Cervasi B Klatt N McClure H Milush JM Staprans S Sodora DL Silvestri G 《Journal of immunology (Baltimore, Md. : 1950)》2007,178(3):1680-1691
In contrast to HIV-infected humans, naturally SIV-infected sooty mangabeys (SMs) very rarely progress to AIDS. Although the mechanisms underlying this disease resistance are unknown, a consistent feature of natural SIV infection is the absence of the generalized immune activation associated with HIV infection. To define the correlates of preserved CD4(+) T cell counts in SMs, we conducted a cross-sectional immunological study of 110 naturally SIV-infected SMs. The nonpathogenic nature of the infection was confirmed by an average CD4(+) T cell count of 1,076 +/- 589/mm(3) despite chronic infection with a highly replicating virus. No correlation was found between CD4(+) T cell counts and either age (used as a surrogate marker for length of infection) or viremia. The strongest correlates of preserved CD4(+) T cell counts were a low percentage of circulating effector T cells (CD28(-)CD95(+) and/or IL-7R/CD127(-)) and a high percentage of CD4(+)CD25(+) T cells. These findings support the hypothesis that the level of immune activation is a key determinant of CD4(+) T cell counts in SIV-infected SMs. Interestingly, we identified 14 animals with CD4(+) T cell counts of <500/mm(3), of which two show severe and persistent CD4(+) T cell depletion (<50/mm(3)). Thus, significant CD4(+) T cell depletion does occasionally follow SIV infection of SMs even in the context of generally low levels of immune activation, lending support to the hypothesis of multifactorial control of CD4(+) T cell homeostasis in this model of infection. The absence of AIDS in these "CD4(low)" naturally SIV-infected SMs defines a protective role of the reduced immune activation even in the context of a significant CD4(+) T cell depletion. 相似文献
13.
Rotavirus replication: plus-sense templates for double-stranded RNA synthesis are made in viroplasms 下载免费PDF全文
Rotavirus plus-strand RNAs not only direct protein synthesis but also serve as templates for the synthesis of the segmented double-stranded RNA (dsRNA) genome. In this study, we identified short-interfering RNAs (siRNAs) for viral genes 5, 8, and 9 that suppressed the expression of NSP1, a nonessential protein; NSP2, a component of viral replication factories (viroplasms); and VP7, an outer capsid protein, respectively. The loss of NSP2 expression inhibited viroplasm formation, genome replication, virion assembly, and synthesis of the other viral proteins. In contrast, the loss of VP7 expression had no effect on genome replication; instead, it inhibited only outer-capsid morphogenesis. Similarly, neither genome replication nor any other event of the viral life cycle was affected by the loss of NSP1. The data indicate that plus-strand RNAs templating dsRNA synthesis within viroplasms are not susceptible to siRNA-induced RNase degradation. In contrast, plus-strand RNAs templating protein synthesis in the cytosol are susceptible to degradation and thus are not the likely source of plus-strand RNAs for dsRNA synthesis in viroplasms. Indeed, immunofluorescence analysis of bromouridine (BrU)-labeled RNA made in infected cells provided evidence that plus-strand RNAs are synthesized within viroplasms. Furthermore, transfection of BrU-labeled viral plus-strand RNA into infected cells suggested that plus-strand RNAs introduced into the cytosol do not localize to viroplasms. From these results, we propose that plus-strand RNAs synthesized within viroplasms are the primary source of templates for genome replication and that trafficking pathways do not exist within the cytosol that transport plus-strand RNAs to viroplasms. The lack of such pathways confounds the development of reverse genetics systems for rotavirus. 相似文献
14.
Cecilia Lopez y Royo Cecilia Silvestri Maylis Salivas-Decaux Gerard Pergent Gianna Casazza 《Hydrobiologia》2009,633(1):169-179
The Biotic Index based on Posidonia oceanica (BiPo) is a classification system for evaluation of the ecological status in Mediterranean coastal waters, developed in accordance with the EU Water Framework requirements. The aim of this study is to verify the applicability and reliability of the BiPo index to different geographical areas of the north-western Mediterranean (France, Spain and Italy), to understand whether such a classification system may be applied more extensively, as so far it has only been applied to coastal waters in Corsica. The ecological status determined for sites is verified against pressures revealed from satellite imagery and from trace metal contamination of plants, to identify the sources of pressure that may be responsible for a low ecological status. The results of this study indicate that: (i) the BiPo index responds reliably to pressures, in different areas of the Mediterranean; (ii) sites with an ecological quality ratio (EQR) close to the good/moderate boundary require particular attention to identify and reduce causes of deterioration; (iii) the support of chemical indicators, in this case metal contamination, is relevant to identify potential sources of pressure. 相似文献
15.
Deoxyribonucleic acid (DNA)-dependent ribonucleic acid (RNA) polymerase (EC 2.7.7.6) isolated from a rifampin-sensitive strain of Mycobacterium smegmatis was 90% inhibited by 1 mug of rifampin per ml; enzyme from a rifampin-resistant mutant was not affected by this concentration of antibiotic. Inhibition of phenylalanine-1-(14)C incorporation by rifampin in growing cultures was complete about 6 min after addition of antibiotic. Under the same conditions, uracil-2-(14)c incorporated was blocked after 1.5 to 2 min. Rifampin kills M. smegmatis very slowly. When rifampin-inhibited cultures were transferred to a rifampin-free medium, there was a partial resumption of uracil-2-(14)C incorporation, even in the presence of chloramphenicol. We conclude that a primary event in the inhibition of M. smegmatis by rifampin is the block of DNA-dependent RNA polymerase. 相似文献
16.
Estimation of anisotropy coefficient of swine pancreas,liver and muscle at 1064 nm based on goniometric technique 下载免费PDF全文
Paola Saccomandi Vitali Vogel Babak Bazrafshan Jürgen Maurer Emiliano Schena Thomas J. Vogl Sergio Silvestri Werner Mäntele 《Journal of biophotonics》2015,8(5):422-428
Optical properties of tissues are required for theoretical modeling of Laser Ablation in tumor therapy. The light scattering characteristic of tissues is described by the anisotropy coefficient, g. The relationship between the angular distribution of scattered light and g is given by the Henyey‐Greenstein (HG) phase function. This work describes the estimation of anisotropy coefficients of ex vivo swine pancreas, liver and muscle at 1064 nm. The intensities of scattered light at fixed angles were measured under repeatability conditions. Experimental data were fitted with a two‐term HG, estimating the anisotropy coefficients for the forward (e.g., 0.956 for pancreas, 0.964 for liver and 0.968 for muscle) and the backward (e.g., –0.481 for pancreas, –0.414 for liver and –0.372 for muscle) scattering.
17.
UVB-radiation-induced apoptosis in Jurkat cells: a coordinated fourier transform infrared spectroscopy-flow cytometry study 总被引:1,自引:0,他引:1
Pozzi D Grimaldi P Gaudenzi S Di Giambattista L Silvestri I Morrone S Congiu Castellano A 《Radiation research》2007,168(6):698-705
We studied the induction of apoptosis in Jurkat cells by UVB radiation (wavelength 290-320 nm) at a dose of 310 mJ/ cm2. We combined Fourier transform infrared (FTIR) spectroscopy with flow cytometry to determine whether the combination of both techniques could provide new and improved information about cell modifications. To do this, we looked for correspondences and correlations between spectroscopy and flow cytometry data and found three highly probable spectroscopic markers of apoptosis. The behavior of the wave number shift of both the Amide I beta-sheet component and the area of the 1083 cm(-1) band reproduced, with a high correlation, the behavior of the early apoptotic cell population, while the behavior of the Amide I area showed a high correlation with the early plus late apoptotic cell population. 相似文献
18.
Katarzyna Malenczyk Magdalena Jazurek Erik Keimpema Cristoforo Silvestri Justyna Janikiewicz Ken Mackie Vincenzo Di Marzo Maria J. Redowicz Tibor Harkany Agnieszka Dobrzyn 《The Journal of biological chemistry》2013,288(45):32685-32699
Endocannabinoid signaling has been implicated in modulating insulin release from β cells of the endocrine pancreas. β Cells express CB1 cannabinoid receptors (CB1Rs), and the enzymatic machinery regulating anandamide and 2-arachidonoylglycerol bioavailability. However, the molecular cascade coupling agonist-induced cannabinoid receptor activation to insulin release remains unknown. By combining molecular pharmacology and genetic tools in INS-1E cells and in vivo, we show that CB1R activation by endocannabinoids (anandamide and 2-arachidonoylglycerol) or synthetic agonists acutely or after prolonged exposure induces insulin hypersecretion. In doing so, CB1Rs recruit Akt/PKB and extracellular signal-regulated kinases 1/2 to phosphorylate focal adhesion kinase (FAK). FAK activation induces the formation of focal adhesion plaques, multimolecular platforms for second-phase insulin release. Inhibition of endocannabinoid synthesis or FAK activity precluded insulin release. We conclude that FAK downstream from CB1Rs mediates endocannabinoid-induced insulin release by allowing cytoskeletal reorganization that is required for the exocytosis of secretory vesicles. These findings suggest a mechanistic link between increased circulating and tissue endocannabinoid levels and hyperinsulinemia in type 2 diabetes. 相似文献
19.
Comparative neurochemical features of the innervation patterns of the gut of the basal actinopterygian,Lepisosteus oculatus,and the euteleost,Clarias batrachus 下载免费PDF全文
Giacomo Zaccone Eugenia Rita Lauriano Giuseppa Silvestri Christopher Kenaley José M. Icardo Simona Pergolizzi Alessio Alesci Manvendra Sengar Michal Kuciel Anita Gopesh 《Acta zoologica》2015,96(2):127-139
The structure and physiology of enteric system are very similar in all classes of vertebrates, although they have been investigated only occasionally in non‐mammalian vertebrates. Very little is known about the distribution of the neurotransmitters in the gut of actinopterygian fishes. Anatomical and physiological studies of enteric nervous systems in the spotted gar (Lepisosteus oculatus) and airbreathing catfish (Clarias batrachus), a non‐teleost and teleost actinopterygian, respectively, have not been undertaken. This study provides the first comprehensive characterization of the range of neurochemical coding in the enteric nervous system of these two species, including the chemical diversity of the mucosal endocrine cells in the pyloric stomach of Clarias. Autonomic innervation of the secretory glands is also described and reported herein for the first time for fishes. We also report splanchnic (spinal) innervation of the stomach, submucosal ganglia (that also colocalize with nNOS) and caudal intestine of Clarias. In both fish species, numerous 5HT, ChAT, nNOS and TH‐positive nerve fibres have been observed. These discoveries demonstrate that much more physiological and pharmacological data are needed before a comprehensive model of enteric nervous system control in vertebrates can be developed. 相似文献
20.
Michael Letko Guido Silvestri Beatrice H. Hahn Frederick Bibollet-Ruche Omer Gokcumen Viviana Simon Marcel Ooms 《Journal of virology》2013,87(21):11861-11871
APOBEC3G (A3G) is a cytidine deaminase that restricts human immunodeficiency virus type 1 (HIV-1) and other lentiviruses. Most of these viruses encode a Vif protein that directly binds A3G and leads to its proteasomal degradation. Both Vif proteins of HIV-1 and African green monkey simian immunodeficiency virus (SIVagm) bind residue 128 of A3G. However, this position does not control the A3G degradation by Vif variants derived from HIV-2 and SIVmac, which both originated from SIV of sooty mangabey monkeys (SIVsmm), suggesting that the A3G binding site for Vif proteins of the SIVsmm/HIV-2 lineage differs from that of HIV-1. To map the SIVsmm Vif binding site of A3G, we performed immunoprecipitations of individual A3G domains, Vif/A3G degradation assays and a detailed mutational analysis of human A3G. We show that A3G residue 129, but not the adjacent position 128, confers susceptibility to degradation by SIVsmm Vif. An artificial A3G mutant, the P129D mutant, was resistant to degradation by diverse Vifs from HIV-1, HIV-2, SIVagm, and chimpanzee SIV (SIVcpz), suggesting a conserved lentiviral Vif binding site. Gorilla A3G naturally contains a glutamine (Q) at position 129, which makes its A3G resistant to Vifs from diverse lineages. We speculate that gorilla A3G serves as a barrier against SIVcpz strains. In summary, we show that Vif proteins from distinct lineages bind to the same A3G loop, which includes positions 128 and 129. The multiple adaptations within this loop among diverse primates underscore the importance of counteracting A3G in lentiviral evolution. 相似文献