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41.
Steven G Thomas Simon DJ Calaminus Jocelyn M Auger Stephen P Watson Laura M Machesky 《BMC cell biology》2007,8(1):46
Background
The platelet cytoskeleton mediates the dramatic change in platelet morphology that takes place upon activation and stabilizes thrombus formation. The Arp2/3 complex plays a vital role in these processes, providing the protrusive force for lamellipodia formation. The Arp2/3 complex is highly regulated by a number of actin-binding proteins including the haematopoietic-specific protein HS1 and its homologue cortactin. The present study investigates the role of HS1 in platelets using HS1-/- mice. 相似文献42.
Andrew C Doxey Daniel A Kurtz Michael DJ Lynch Laura A Sauder Josh D Neufeld 《The ISME journal》2015,9(2):461-471
Cobalamin (vitamin B12) is a complex metabolite and essential cofactor required by many branches of life, including most eukaryotic phytoplankton. Algae and other cobalamin auxotrophs rely on environmental cobalamin supplied from a relatively small set of cobalamin-producing prokaryotic taxa. Although several Bacteria have been implicated in cobalamin biosynthesis and associated with algal symbiosis, the involvement of Archaea in cobalamin production is poorly understood, especially with respect to the Thaumarchaeota. Based on the detection of cobalamin synthesis genes in available thaumarchaeotal genomes, we hypothesized that Thaumarchaeota, which are ubiquitous and abundant in aquatic environments, have an important role in cobalamin biosynthesis within global aquatic ecosystems. To test this hypothesis, we examined cobalamin synthesis genes across sequenced thaumarchaeotal genomes and 430 metagenomes from a diverse range of marine, freshwater and hypersaline environments. Our analysis demonstrates that all available thaumarchaeotal genomes possess cobalamin synthesis genes, predominantly from the anaerobic pathway, suggesting widespread genetic capacity for cobalamin synthesis. Furthermore, although bacterial cobalamin genes dominated most surface marine metagenomes, thaumarchaeotal cobalamin genes dominated metagenomes from polar marine environments, increased with depth in marine water columns, and displayed seasonality, with increased winter abundance observed in time-series datasets (e.g., L4 surface water in the English Channel). Our results also suggest niche partitioning between thaumarchaeotal and cyanobacterial ribosomal and cobalamin synthesis genes across all metagenomic datasets analyzed. These results provide strong evidence for specific biogeographical distributions of thaumarchaeotal cobalamin genes, expanding our understanding of the global biogeochemical roles played by Thaumarchaeota in aquatic environments. 相似文献
43.
Samir Satih Hélène Savinel Nadège Rabiau Luc Fontana Yves-Jean Bignon Dominique J Bernard-Gallon 《Journal of molecular signaling》2009,4(1):1-12
Background
Most of breast cancers are considered sporadic and modulation of the two major genes BRCA1 and BRCA2 expressions caused by tissue-specific somatic mutations lead to this pathology. The nutritional intake of phytoestrogens seems to reduce the risk of breast cancer and investigation of their potential as anticancer agents has increased. However, the possible mechanisms and signalling pathways of phytoestrogen action in breast cancer prevention remains unknown.Results
Using Taqman Low Density Array technology, we investigated the BRCA2 loss of function role in sporadic breast cancers and the links existing with soy isoflavones on a panel of nuclear receptor expression. Human breast cell lines (MCF-7, MDA-MB-231, and MCF-10a) were transfected by BRCA2-siRNA and treated with genistein (18.5 μM) or daidzein (78.5 μM) for 72 h. Generating the transitory knockdown of BRCA2 oncosuppressor, we observed different modulations in several nuclear receptor genes such as ER, RAR and RXR, as well as PPARs and VDR according to the studied breast cell line. Additional isoflavone treatments showed different nuclear receptor gene modulation profiles.Conclusion
Our results seemed to implicate the oncosuppressor BRCA2 and the phytoestrogen pathways in different nuclear gene expressions via an ER-independent manner. 相似文献44.
This article selectively reviews research concerning nicotine's effects on cognition, including the neurobiological mechanism for these effects, task and experimental features that may be important for elucidating these effects, and why these effects may have amplified motivational significance among smokers with cognitive deficit. Nicotine has effects on various cognitive processes, though most studies in humans have focused on the amelioration of cognitive deficits experienced during drug withdrawal. The direct cognitive-enhancing effect of nicotine remains a controversial topic. The relationship between attentional and non-attentional cognitive effects of nicotine is discussed in the context of cognitive self-medication. Further research should include theory-driven examination of cognitive effects of nicotine, and develop targeted smoking cessation programs based on an improved understanding of the role of cognitive self-medication in high-risk individuals. 相似文献
45.
46.
Theoretical considerations have shown that the five possible overlapping
reading-frame configurations differ significantly in their coding
flexibility and thus in their information content (Siegel and Fitch 1980;
Smith and Waterman 1980). Contrary to expectation, the overlapping frame
configuration allowing the greatest coding flexibility is rarely seen,
whereas one of the most constraining is common. We point out here that this
overlapping reading-frame paradox and an observed but unexplained
preference in coding regions for a pyrimidine-purine at codon boundaries
(Shepherd 1981; Jones and Kafatos 1982; Smith et al. 1983) are intimately
linked. The codon boundary preference, which may be related to translation
efficiency or accuracy, places constraints on the evolution of overlapping
coding regions. These considerations may help identify actual coding
regions in DNA sequences. We have analyzed five sequenced (enteric)
bacterial insertion sequences for codon boundary incidences and
reading-frame configurations and find that they are consistent with these
proposed constraints.
相似文献
47.
Coronary angiographic trials have demonstrated that lowering cholesterol can slow the progression of atherosclerosis, limit the formation of new lesions and enhance atherosclerotic regression together with reducing the incidence of clinical events (Waters D, 1996). Spontaneous regression of coronary atherosclerotic lesions is rare. We report the case of a patient with a severe within-stent restenotic lesion whose coronary disease spontaneously regressed 12 months after initial diagnosis, allowing for medical treatment of symptoms rather than repeated intervention. (Int J Cardiovasc Interventions 1999; 2: 121-123) 相似文献
48.
S. N. Suresh Aravinda K. Chavalmane Vidyadhara DJ Haorei Yarreiphang Shashank Rai Abhik Paul 《Autophagy》2017,13(7):1221-1234
Parkinson disease (PD) is a life-threatening neurodegenerative movement disorder with unmet therapeutic intervention. We have identified a small molecule autophagy modulator, 6-Bio that shows clearance of toxic SNCA/α-synuclein (a protein implicated in synucleopathies) aggregates in yeast and mammalian cell lines. 6-Bio induces autophagy and dramatically enhances autolysosome formation resulting in SNCA degradation. Importantly, neuroprotective function of 6-Bio as envisaged by immunohistology and behavior analyses in a preclinical model of PD where it induces autophagy in dopaminergic (DAergic) neurons of mice midbrain to clear toxic protein aggregates suggesting that it could be a potential therapeutic candidate for protein conformational disorders. 相似文献
49.
Andrew C Doxey Michael DJ Lynch Kirsten M Müller Elizabeth M Meiering Brendan J McConkey 《BMC evolutionary biology》2008,8(1):316
Background
Clostridial neurotoxins (CNTs) are the most deadly toxins known and causal agents of botulism and tetanus neuroparalytic diseases. Despite considerable progress in understanding CNT structure and function, the evolutionary origins of CNTs remain a mystery as they are unique to Clostridium and possess a sequence and structural architecture distinct from other protein families. Uncovering the origins of CNTs would be a significant contribution to our understanding of how pathogens evolve and generate novel toxin families. 相似文献50.
Cécile Vissac Didier Lémery Ludovic Le Corre Pierre Fustier Pierre Déchelotte Jean Claude Maurizis Yves Jean Bignon Dominique J Bernard-Gallon 《Biochimica et biophysica acta》2002,1586(1):50-56
We evaluated BRCA1 and BRCA2 oncosuppressor protein expression in 26 milk samples in women just after delivery. The quantification of BRCA1 and BRCA2 proteins was performed in isolated milk fat globules using an affinity chromatography strategy. The amounts of BRCA1 and BRCA2 proteins were found to be similar. We explained the presence of BRCA1 and BRCA2 proteins in human milk fat globules by the fact that they are formed by exocytosis of lipids from epithelial cells of the mammary gland and are enveloped by plasma membrane from the apical part of the milk-secreting cells. This raises the possibility that BRCA1 and BRCA2 proteins are a protective response to proliferation and play a possible role in newborn nutrition. 相似文献