Search results for " Complement"
showing 10 items of 753 documents
Black hole entropy in loop quantum gravity
2012
4 pags., 2 figs. -- Loops 11: Non-Perturbative / Background Independent Quantum Gravity 23–28 May 2011, Madrid, Spain
Black hole state counting in loop quantum gravity: a number-theoretical approach
2008
4 pages, 1 figure.-- PACS nrs.: 04.70.Dy, 04.60.Pp.-- ArXiv pre-print available at: http://arxiv.org/abs/0802.4077
Black hole state degeneracy in Loop Quantum Gravity
2008
The combinatorial problem of counting the black hole quantum states within the Isolated Horizon framework in Loop Quantum Gravity is analyzed. A qualitative understanding of the origin of the band structure shown by the degeneracy spectrum, which is responsible for the black hole entropy quantization, is reached. Even when motivated by simple considerations, this picture allows to obtain analytical expressions for the most relevant quantities associated to this effect.
Thermostability of Two Cyanobacterial GrpE Thermosensors
2011
GrpE proteins act as co-chaperones for DnaK heat-shock proteins. The dimeric protein unfolds under heat stress conditions, which results in impaired interaction with a DnaK protein. Since interaction of GrpE with DnaK is crucial for the DnaK chaperone activity, GrpE proteins act as a thermosensor in bacteria. Here we have analyzed the thermostability and function of two GrpE homologs of the mesophilic cyanobacterium Synechocystis sp. PCC 6803 and of the thermophilic cyanobacterium Thermosynechococcus elongatus BP1. While in Synechocystis an N-terminal helix pair of the GrpE dimer appears to be the thermosensing domain and mainly mediates GrpE dimerization, the C-terminal four-helix bundle i…
The Arabidopsis COPT6 Transport Protein Functions in Copper Distribution Under Copper-Deficient Conditions
2013
Copper (Cu), an essential redox active cofactor, participates in fundamental biological processes, but it becomes highly cytotoxic when present in excess. Therefore, living organisms have established suitable mechanisms to balance cellular and systemic Cu levels. An important strategy to maintain Cu homeostasis consists of regulating uptake and mobilization via the conserved family of CTR/COPT Cu transport proteins. In the model plant Arabidopsis thaliana, COPT1 protein mediates root Cu acquisition, whereas COPT5 protein functions in Cu mobilization from intracellular storage organelles. The function of these transporters becomes critical when environmental Cu bioavailability diminishes. Ho…
Functional characterization of the plastidial 3-phosphoglycerate dehydrogenase family in Arabidopsis.
2013
This work contributes to unraveling the role of the phosphorylated pathway of serine (Ser) biosynthesis in Arabidopsis (Arabidopsis thaliana) by functionally characterizing genes coding for the first enzyme of this pathway, 3-phosphoglycerate dehydrogenase (PGDH). We identified two Arabidopsis plastid-localized PGDH genes (3-PGDH and EMBRYO SAC DEVELOPMENT ARREST9 [EDA9]) with a high percentage of amino acid identity with a previously identified PGDH. All three genes displayed a different expression pattern indicating that they are not functionally redundant. pgdh and 3-pgdh mutants presented no drastic visual phenotypes, but eda9 displayed delayed embryo development, leading to aborted emb…
A critical role of plastidial glycolytic Glyceraldehyde-3-Phosphate Dehydrogenase in the control of plant metabolism and development
2009
3 páginas.
Mouse embryonic stem cells are hypersensitive to apoptosis triggered by the DNA damage O(6)-methylguanine due to high E2F1 regulated mismatch repair.
2007
Exposure of stem cells to genotoxins may lead to embryonic lethality or teratogenic effects. This can be prevented by efficient DNA repair or by eliminating genetically damaged cells. Using undifferentiated mouse embryonic stem (ES) cells as a pluripotent model system, we compared ES cells with differentiated cells, with regard to apoptosis induction by alkylating agents forming the highly mutagenic and killing DNA adduct O(6)-methylguanine. Upon treatment with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), ES cells undergo apoptosis at much higher frequency than differentiated cells, although they express a high level of the repair protein O(6)-methylguanine-DNA methyltransferase (MGMT). Apo…
François Le Lionnais and the Oulipo. The Unexpected Role of Mathematics in Literature
2020
“The true spirit of delight, the exaltation, the sense of being more than Man, which is the touchstone of the highest excellence, is to be found in mathematics as surely as poetry” (Bertrand Russel, Mysticism and Logic, 1910). This sentence, quoted by François Le Lionnais in his work La Beauté en Mathématiques in [1], reflects his conception of a deep bond between mathematics and literature. He had a multifaceted education and was an erudite and founder of the Oulipo with Raymond Queneau. Even though he was neither a “professional” mathematician nor a “professional” man of letters but only an épicurien passionné as he defined himself [2],1 while alive, he channelled his interests in the the…
Sequence evolution, processing, and posttranslational modification of zonadhesin D domains in primates, as inferred from cDNA data
2005
Zonadhesin is a mammalian transmembrane sperm ligand. Precursor zonadhesin essentially consists of MAM (meprin/A5 antigen/mu receptor tyrosine phosphatase) domains, a mucin-like repeat, and D domains (homologous to von Willebrand D). Recent immunovisualization and binding assays indicate that zonadhesin D domains 1–3 bind postacrosomally to the zona pellucida. This feature has attracted considerable interest in the evolution of zonadhesin and its possible biological and biomedical implications. Previous molecular evolutionary analyses, however, were confined to cDNA sequences of only few distantly related species. Moreover, except for rabbit and pig, little is known about zonadhesin’s proce…