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排序方式: 共有100条查询结果,搜索用时 31 毫秒
71.
Basil P Hubbard Christine Loh Ana P Gomes Jun Li Quinn Lu Taylor LG Doyle Jeremy S Disch Sean M Armour James L Ellis George P Vlasuk David A Sinclair 《Cell cycle (Georgetown, Tex.)》2013,12(14):2233-2240
SIRT1 is an NAD+-dependent deacetylase that counteracts multiple disease states associated with aging and may underlie some of the health benefits of calorie restriction. Understanding how SIRT1 is regulated in vivo could therefore lead to new strategies to treat age-related diseases. SIRT1 forms a stable complex with DBC1, an endogenous inhibitor. Little is known regarding the biochemical nature of SIRT1-DBC1 complex formation, how it is regulated and whether or not it is possible to block this interaction pharmacologically. In this study, we show that critical residues within the catalytic core of SIRT1 mediate binding to DBC1 via its N-terminal region, and that several carboxamide SIRT1 inhibitors, including EX-527, can completely block this interaction. We identify two acetylation sites on DBC1 that regulate its ability to bind SIRT1 and suppress its activity. Furthermore, we show that DBC1 itself is a substrate for SIRT1. Surprisingly, the effect of EX-527 on SIRT1-DBC1 binding is independent of DBC1 acetylation. Together, these data show that protein acetylation serves as an endogenous regulatory mechanism for SIRT1-DBC1 binding and illuminate a new path to developing small-molecule modulators of SIRT1. 相似文献
72.
Antonio Canu Massimo Scandura Sara Luchetti Antonio Cossu Laura Iacolina Marco Bazzanti Marco Apollonio 《European Journal of Wildlife Research》2013,59(6):783-793
In many areas, the management of overexploited populations of brown hare (Lepus europaeus) is based on annual restocking. While in some cases exotic hares are introduced, in some others hares are captured locally within protected areas and subsequently released into hunting grounds. We evaluated the genetic effects of this management regime in an Italian province where the brown hare population has recovered in the last few decades, by sequencing the hypervariable domain 1 of the mitochondrial control region and by genotyping eight autosomal microsatellites in hares sampled in both hunting and non-hunting areas. Both nuclear (H e?=?0.68 and H o?=?0.65) and mitochondrial variability (h?=?0.853 and π?=?0.012) were in line with other European populations. When comparing our data with mitochondrial sequences retrieved from GenBank, out of the 21 detected haplotypes, 14 were private to our study area. While 4.6 % of the individuals were found to carry haplotypes attributable to past introductions, 41.5 % grouped within a well-supported lineage, previously identified with a presumed native Italian taxon, L. e. meridiei. Despite the detectable geographic partitioning of mitochondrial haplotypes across the province, no genetic structure resulted from microsatellites analysis, indicating that no reproductive barriers exist among hares carrying different mitochondrial lineages. In conclusion, the local management seems to have contributed to the recovery of the species and to a full admixture of nuclear genes in the province. However, neither the extensive translocations nor the possible introductions of exotic heads seem to have completely undermined the local mitochondrial lineages. 相似文献
73.
Antigenic analysis of potato virus A particles and coat protein 总被引:2,自引:0,他引:2
LEENA ANDREEVA LILIAN JÄRVEKÜLG F RABENSTEIN LESLEY TORRANCE B D HARRISON M SAARMA 《The Annals of applied biology》1994,125(2):337-348
Five monoclonal antibodies (MAbs) were prepared to particles of potato virus A (PVA), isolate B11. In immunoblots, MAbs A1D8 and A5B6 reacted only with full length molecules of PVA coat protein (CP). Pepscan tests with overlapping octapeptides representing the whole sequence of PVA CP showed that the epitope detected by MAb A5B6 is contained in its N-terminal octapeptide. MAbs A9A4, A3H4 and A6B8 reacted with CP molecules that lacked about 5 kD of sequence at their end(s) and detected epitopes at residues 52 to 62, 64 to 73 and 75 to 82 respectively, all of which lie in the protease-resistant core of the CP. The epitope which reacts with MAb A3H4 is in a region predicted to be hydrophobic and is not detected in intact virus particles, indicating it is a cryptotope. In contrast, MAbs A6B8 and A9A4 reacted with freshly purified PVA particles but more strongly with partially degraded ones. Pepscan tests with polyclonal antibodies to PVA isolate B11 identified five additional immunogenic sequences in PVA CP and showed that regions at the N-termini of the intact and core molecules are immunodominant. PVA isolate B11 was not transmitted by aphids, and its CP N-terminal octapeptide contains the sequence DAS, which is associated with aphid-non-transmissibility in other potyviruses. MAb A5B6, which detects this region, reacted strongly in ELISA with three out of four other aphid-non-transmissible PVA isolates but only weakly with three aphid-transmissible ones, suggesting that differences in N-terminal sequence may underlie most of the differences in aphid transmissibility. 相似文献
74.
Platano D Mesirca P Paffi A Pellegrino M Liberti M Apollonio F Bersani F Aicardi G 《Bioelectromagnetics》2007,28(8):599-607
We have studied the non-thermal effects of radiofrequency (RF) electromagnetic fields (EMFs) on Ba(2+) currents (I Ba 2+) through voltage-gated calcium channels (VGCC), recorded in primary cultures of rat cortical neurons using the patch-clamp technique. To assess whether low-level acute RF field exposure could modify the amplitude and/or the voltage-dependence of I Ba 2+, Petri dishes containing cultured neurons were exposed for 1-3 periods of 90 s to 900 MHz RF-EMF continuous wave (CW) or amplitude-modulated according to global system mobile communication standard (GSM) during whole-cell recording. The specific absorption rates (SARs) were 2 W/kg for CW and 2 W/kg (time average value) for GSM-modulated signals, respectively. The results obtained indicate that single or multiple acute exposures to either CW or GSM-modulated 900 MHz RF-EMFs do not significantly alter the current amplitude or the current-voltage relationship of I Ba 2+, through VGCC. 相似文献
75.
Marinus FW te Pas Ina Hulsegge Albart Coster Marco H Pool Henri H Heuven Luc LG Janss 《BMC developmental biology》2007,7(1):66
Background
Combining microarray results and biological pathway information will add insight into biological processes. Pathway information is widely available in databases through the internet. 相似文献76.
77.
78.
F. Scaramuzzi G. Apollonio S. D'Emerico 《In vitro cellular & developmental biology. Plant》2000,36(5):379-382
Summary In our wide-ranging research on in vitro propagation of some monocotyledonous plants, two Commelinaceae species were studied: Tradescantia fluminensis var. foliis variegatis and Tradescantia pallida. Initial cultures were established successfully using nodal and apical meristems that produced single shoots, many roots,
and no callus, by utilizing growth regulator-free MS medium. Addition of growth regulators did not increase the activity of
explants that produced single or multiple shoots, atypical roots, and no callus. Consecutive cultures were possible using
the apical and nodal meristems of the previous generation. The behavior of the different generations in culture did not change
and was similar to the initial cultures. Their growth capacity was maintained over many months, also on a growth regulator-free
medium. In both species, the chromosome number in the root tips of the mother plant and all morphologically stable in vitro plantlets confirmed a constant ploidy level, in T. fluminensis 2n=72, and in T. pallida 2n=24. 相似文献
79.
F. Scaramuzzi G. Apollonio S. D’Emerico 《In vitro cellular & developmental biology. Plant》1999,35(3):217-221
Summary Leaf explants of Sinningia speciosa were cultured in vitro on Murashige and Skoog (MS) basal medium with various growth substances in order to regenerate shoots.
On MS medium supplemented with indoleacetic acid (IAA) and kinetin, 80% of the explants produced green callus and 25 to 30
shoots with roots per explant. On MS supplemented with IAA and N6 benzyladenine (BA), 80% of the explants produced green callus and 40 to 50 shoots per explant but lacked roots. After 3–4
mo., these shoots were removed from the initial explants and transferred separately onto MS supplemented with indolebutyric
acid for their elongation and successive rooting (3 mo.). Histological studies showed that the callus was associated with
mesophyll cell layers, primarily with the spongy parenchyma. The shoots regenerated at the callus surface and were associated
with newly differentiated vascular areas. Recurrent regenerations were obtained from leaf explants or apical meristems excised
from shoots of the previous subcultures. These explants, as compared to initial cultures, had a high frequency of regeneration
and also produced more shoots per explant. Chromosome numbers of root tip cells of the mother plant and of all in vitro-regenerated
plants remained constant: 2n=26. 相似文献
80.
In limulus sperm an actin filament bundle 55 mum in length extends from the acrosomal vacuole membrane through a canal in the nucleus and then coils in a regular fashion around the base of the nucleus. The bundle expands systematically from 15 filaments near the acrosomal vacuole to 85 filaments at the basal end. Thin sections of sperm fixed during stages in spermatid maturation reveal that the filament bundle begins to assemble on dense material attached to the acrosomal vacuole membrane. In micrographs fo these early stages in maturation, short bundles are seen extending posteriorly from the dense material. The significance is that these short, developing bundles have about 85 filaments, suggesting that the 85-filament end of the bundle is assembled first. By using filament bundles isolated and incubated in vitro with G actin from muscle, we can determine the end “preferred” for addition of actin monomers during polymerization. The end that would be associated with the acrosomal vacuole membrane, a membrane destined to be continuous with the plasma membrane, is preferred about 10 times over the other, thicker end. Decoration of the newly polymerized portions of the filament bundle with subfragment 1 of myosin reveals that the arrowheads point away from the acrosomal vacuole membrane, as is true of other actin filament bundles attached to membranes. From these observations we conclude that the bundle is nucleated from the dense material associated with the acrosomal vacuole and that monomers are added to the membrane-associated end. As monomers are added at the dense material, the thick first-made end of the filament bundle is pushed down through the nucleus where, upon reaching the base of the nucleus, it coils up. Tapering is brought about by the capping of the peripheral filaments in the bundle. 相似文献